wip: grok provider abstraction

This threads typed hook settings through runtime config, adds a shell-based hook runner, and executes PreToolUse/PostToolUse around each tool call in the conversation loop. The CLI now rebuilds runtimes with settings-derived hook configuration so user-defined Claude hook commands actually run before and after tools.

Constraint: Hook behavior needed to match Claude-style settings.json hooks without broad plugin/MCP parity work in this change
Rejected: Delay hook loading to the tool executor layer | would miss denied tool calls and duplicate runtime policy plumbing
Confidence: medium
Scope-risk: moderate
Reversibility: clean
Directive: Keep hook execution in the runtime loop so permission decisions and tool results remain wrapped by the same conversation semantics
Tested: cargo test; cargo build --release
Not-tested: Real user hook scripts outside the test harness; broader plugin/skills parity

.claude.json

@@ -0,0 +1,5 @@
+{
+  "permissions": {
+    "defaultMode": "dontAsk"
+  }
+}

.gitignore

@@ -2,3 +2,6 @@ __pycache__/
 archive/
 .omx/
 .clawd-agents/
+# Claude Code local artifacts
+.claude/settings.local.json
+.claude/sessions/

CLAUDE.md

@@ -0,0 +1,21 @@
+# CLAUDE.md
+
+This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
+
+## Detected stack
+- Languages: Rust.
+- Frameworks: none detected from the supported starter markers.
+
+## Verification
+- Run Rust verification from `rust/`: `cargo fmt`, `cargo clippy --workspace --all-targets -- -D warnings`, `cargo test --workspace`
+- `src/` and `tests/` are both present; update both surfaces together when behavior changes.
+
+## Repository shape
+- `rust/` contains the Rust workspace and active CLI/runtime implementation.
+- `src/` contains source files that should stay consistent with generated guidance and tests.
+- `tests/` contains validation surfaces that should be reviewed alongside code changes.
+
+## Working agreement
+- Prefer small, reviewable changes and keep generated bootstrap files aligned with actual repo workflows.
+- Keep shared defaults in `.claude.json`; reserve `.claude/settings.local.json` for machine-local overrides.
+- Do not overwrite existing `CLAUDE.md` content automatically; update it intentionally when repo workflows change.

rust/.claude/sessions/session-1775012674485.json

@@ -0,0 +1 @@
+{"messages":[{"blocks":[{"text":"clear","type":"text"}],"role":"user"},{"blocks":[{"text":"\n\nI've cleared the conversation. How can I help you today?","type":"text"}],"role":"assistant","usage":{"cache_creation_input_tokens":0,"cache_read_input_tokens":0,"input_tokens":4272,"output_tokens":17}}],"version":1}

rust/.claude/sessions/session-1775012687059.json

@@ -0,0 +1 @@
+{"messages":[{"blocks":[{"text":"exit","type":"text"}],"role":"user"},{"blocks":[{"text":"\n\nGoodbye! 👋","type":"text"}],"role":"assistant","usage":{"cache_creation_input_tokens":0,"cache_read_input_tokens":0,"input_tokens":4272,"output_tokens":10}}],"version":1}

rust/.claude/sessions/session-1775013221875.json

@@ -0,0 +1 @@
+{"messages":[],"version":1}

rust/.clawd-todos.json

@@ -1,22 +1,27 @@
 [
   {
-    "content": "Phase 0: Structural Cleanup — spawn 4 agents for 0.1-0.4",
+    "content": "Architecture & dependency analysis",
-    "activeForm": "Executing Phase 0: Structural Cleanup via sub-agents",
+    "activeForm": "Complete",
+    "status": "completed"
+  },
+  {
+    "content": "Runtime crate deep analysis",
+    "activeForm": "Complete",
+    "status": "completed"
+  },
+  {
+    "content": "CLI & Tools analysis",
+    "activeForm": "Complete",
+    "status": "completed"
+  },
+  {
+    "content": "Code quality verification",
+    "activeForm": "Complete",
+    "status": "completed"
+  },
+  {
+    "content": "Synthesize findings into unified report",
+    "activeForm": "Writing report",
     "status": "in_progress"
-  },
-  {
-    "content": "Phase 1.1-1.2: Status bar with live HUD and token counter",
-    "activeForm": "Awaiting Phase 0",
-    "status": "pending"
-  },
-  {
-    "content": "Phase 2.4: Remove artificial 8ms stream delay",
-    "activeForm": "Awaiting Phase 0",
-    "status": "pending"
-  },
-  {
-    "content": "Phase 3.1: Collapsible tool output",
-    "activeForm": "Awaiting Phase 0",
-    "status": "pending"
   }
 ]

rust/Cargo.lock

@@ -1545,10 +1545,12 @@ dependencies = [
 name = "tools"
 version = "0.1.0"
 dependencies = [
+ "api",
  "reqwest",
  "runtime",
  "serde",
  "serde_json",
+ "tokio",
 ]
 
 [[package]]

rust/README.md

@@ -1,230 +1,149 @@
-# Rusty Claude CLI
+# 🦞 Claw Code — Rust Implementation
 
-`rust/` contains the Rust workspace for the integrated `rusty-claude-cli` deliverable.
+A high-performance Rust rewrite of the Claude Code CLI agent harness. Built for speed, safety, and native tool execution.
-It is intended to be something you can clone, build, and run directly.
 
-## Workspace layout
+## Quick Start
 
-```text
+```bash
+# Build
+cd rust/
+cargo build --release
+
+# Run interactive REPL
+./target/release/claw
+
+# One-shot prompt
+./target/release/claw prompt "explain this codebase"
+
+# With specific model
+./target/release/claw --model sonnet prompt "fix the bug in main.rs"
+```
+
+## Configuration
+
+Set your API credentials:
+
+```bash
+export ANTHROPIC_API_KEY="sk-ant-..."
+# Or use a proxy
+export ANTHROPIC_BASE_URL="https://your-proxy.com"
+```
+
+Or authenticate via OAuth:
+
+```bash
+claw login
+```
+
+## Features
+
+| Feature | Status |
+|---------|--------|
+| Anthropic API + streaming | ✅ |
+| OAuth login/logout | ✅ |
+| Interactive REPL (rustyline) | ✅ |
+| Tool system (bash, read, write, edit, grep, glob) | ✅ |
+| Web tools (search, fetch) | ✅ |
+| Sub-agent orchestration | ✅ |
+| Todo tracking | ✅ |
+| Notebook editing | ✅ |
+| CLAUDE.md / project memory | ✅ |
+| Config file hierarchy (.claude.json) | ✅ |
+| Permission system | ✅ |
+| MCP server lifecycle | ✅ |
+| Session persistence + resume | ✅ |
+| Extended thinking (thinking blocks) | ✅ |
+| Cost tracking + usage display | ✅ |
+| Git integration | ✅ |
+| Markdown terminal rendering (ANSI) | ✅ |
+| Model aliases (opus/sonnet/haiku) | ✅ |
+| Slash commands (/status, /compact, /clear, etc.) | ✅ |
+| Hooks (PreToolUse/PostToolUse) | 🔧 Config only |
+| Plugin system | 📋 Planned |
+| Skills registry | 📋 Planned |
+
+## Model Aliases
+
+Short names resolve to the latest model versions:
+
+| Alias | Resolves To |
+|-------|------------|
+| `opus` | `claude-opus-4-6` |
+| `sonnet` | `claude-sonnet-4-6` |
+| `haiku` | `claude-haiku-4-5-20251213` |
+
+## CLI Flags
+
+```
+claw [OPTIONS] [COMMAND]
+
+Options:
+  --model MODEL                    Set the model (alias or full name)
+  --dangerously-skip-permissions   Skip all permission checks
+  --permission-mode MODE           Set read-only, workspace-write, or danger-full-access
+  --allowedTools TOOLS             Restrict enabled tools
+  --output-format FORMAT           Output format (text or json)
+  --version, -V                    Print version info
+
+Commands:
+  prompt <text>      One-shot prompt (non-interactive)
+  login              Authenticate via OAuth
+  logout             Clear stored credentials
+  init               Initialize project config
+  doctor             Check environment health
+  self-update        Update to latest version
+```
+
+## Slash Commands (REPL)
+
+| Command | Description |
+|---------|-------------|
+| `/help` | Show help |
+| `/status` | Show session status (model, tokens, cost) |
+| `/cost` | Show cost breakdown |
+| `/compact` | Compact conversation history |
+| `/clear` | Clear conversation |
+| `/model [name]` | Show or switch model |
+| `/permissions` | Show or switch permission mode |
+| `/config [section]` | Show config (env, hooks, model) |
+| `/memory` | Show CLAUDE.md contents |
+| `/diff` | Show git diff |
+| `/export [path]` | Export conversation |
+| `/session [id]` | Resume a previous session |
+| `/version` | Show version |
+
+## Workspace Layout
+
+```
 rust/
-├── Cargo.toml
+├── Cargo.toml              # Workspace root
 ├── Cargo.lock
-├── README.md
 └── crates/
-    ├── api/               # Anthropic API client + SSE streaming support
+    ├── api/                # Anthropic API client + SSE streaming
-    ├── commands/          # Shared slash-command metadata/help surfaces
+    ├── commands/           # Shared slash-command registry
-    ├── compat-harness/    # Upstream TS manifest extraction harness
+    ├── compat-harness/     # TS manifest extraction harness
-    ├── runtime/           # Session/runtime/config/prompt orchestration
+    ├── runtime/            # Session, config, permissions, MCP, prompts
-    ├── rusty-claude-cli/  # Main CLI binary
+    ├── rusty-claude-cli/   # Main CLI binary (`claw`)
-    └── tools/             # Built-in tool implementations
+    └── tools/              # Built-in tool implementations
 ```
 
-## Prerequisites
+### Crate Responsibilities
 
-- Rust toolchain installed (`rustup`, stable toolchain)
+- **api** — HTTP client, SSE stream parser, request/response types, auth (API key + OAuth bearer)
-- Network access and Anthropic credentials for live prompt/REPL usage
+- **commands** — Slash command definitions and help text generation
+- **compat-harness** — Extracts tool/prompt manifests from upstream TS source
+- **runtime** — `ConversationRuntime` agentic loop, `ConfigLoader` hierarchy, `Session` persistence, permission policy, MCP client, system prompt assembly, usage tracking
+- **rusty-claude-cli** — REPL, one-shot prompt, streaming display, tool call rendering, CLI argument parsing
+- **tools** — Tool specs + execution: Bash, ReadFile, WriteFile, EditFile, GlobSearch, GrepSearch, WebSearch, WebFetch, Agent, TodoWrite, NotebookEdit, Skill, ToolSearch, REPL runtimes
 
-## Build
+## Stats
 
-From the repository root:
+- **~20K lines** of Rust
+- **6 crates** in workspace
+- **Binary name:** `claw`
+- **Default model:** `claude-opus-4-6`
+- **Default permissions:** `danger-full-access`
 
-```bash
+## License
-cd rust
-cargo build --release -p rusty-claude-cli
-```
 
-The optimized binary will be written to:
+See repository root.
-
-```bash
-./target/release/rusty-claude-cli
-```
-
-## Test
-
-Run the verified workspace test suite used for release-readiness:
-
-```bash
-cd rust
-cargo test --workspace --exclude compat-harness
-```
-
-## Quick start
-
-### Show help
-
-```bash
-cd rust
-cargo run -p rusty-claude-cli -- --help
-```
-
-### Print version
-
-```bash
-cd rust
-cargo run -p rusty-claude-cli -- --version
-```
-
-### Login with OAuth
-
-Configure `settings.json` with an `oauth` block containing `clientId`, `authorizeUrl`, `tokenUrl`, optional `callbackPort`, and optional `scopes`, then run:
-
-```bash
-cd rust
-cargo run -p rusty-claude-cli -- login
-```
-
-This opens the browser, listens on the configured localhost callback, exchanges the auth code for tokens, and stores OAuth credentials in `~/.claude/credentials.json` (or `$CLAUDE_CONFIG_HOME/credentials.json`).
-
-### Logout
-
-```bash
-cd rust
-cargo run -p rusty-claude-cli -- logout
-```
-
-This removes only the stored OAuth credentials and preserves unrelated JSON fields in `credentials.json`.
-
-### Self-update
-
-```bash
-cd rust
-cargo run -p rusty-claude-cli -- self-update
-```
-
-The command checks the latest GitHub release for `instructkr/clawd-code`, compares it to the current binary version, downloads the matching binary asset plus checksum manifest, verifies SHA-256, replaces the current executable, and prints the release changelog. If no published release or matching asset exists, it exits safely with an explanatory message.
-
-## Usage examples
-
-### 1) Prompt mode
-
-Send one prompt, stream the answer, then exit:
-
-```bash
-cd rust
-cargo run -p rusty-claude-cli -- prompt "Summarize the architecture of this repository"
-```
-
-Use a specific model:
-
-```bash
-cd rust
-cargo run -p rusty-claude-cli -- --model claude-sonnet-4-20250514 prompt "List the key crates in this workspace"
-```
-
-Restrict enabled tools in an interactive session:
-
-```bash
-cd rust
-cargo run -p rusty-claude-cli -- --allowedTools read,glob
-```
-
-Bootstrap Claude project files for the current repo:
-
-```bash
-cd rust
-cargo run -p rusty-claude-cli -- init
-```
-
-### 2) REPL mode
-
-Start the interactive shell:
-
-```bash
-cd rust
-cargo run -p rusty-claude-cli --
-```
-
-Inside the REPL, useful commands include:
-
-```text
-/help
-/status
-/model claude-sonnet-4-20250514
-/permissions workspace-write
-/cost
-/compact
-/memory
-/config
-/init
-/diff
-/version
-/export notes.txt
-/sessions
-/session list
-/exit
-```
-
-### 3) Resume an existing session
-
-Inspect or maintain a saved session file without entering the REPL:
-
-```bash
-cd rust
-cargo run -p rusty-claude-cli -- --resume session-123456 /status /compact /cost
-```
-
-You can also inspect memory/config state for a restored session:
-
-```bash
-cd rust
-cargo run -p rusty-claude-cli -- --resume ~/.claude/sessions/session-123456.json /memory /config
-```
-
-## Available commands
-
-### Top-level CLI commands
-
-- `prompt <text...>` — run one prompt non-interactively
-- `--resume <session-id-or-path> [/commands...]` — inspect or maintain a saved session stored under `~/.claude/sessions/`
-- `dump-manifests` — print extracted upstream manifest counts
-- `bootstrap-plan` — print the current bootstrap skeleton
-- `system-prompt [--cwd PATH] [--date YYYY-MM-DD]` — render the synthesized system prompt
-- `self-update` — update the installed binary from the latest GitHub release when a matching asset is available
-- `--help` / `-h` — show CLI help
-- `--version` / `-V` — print the CLI version and build info locally (no API call)
-- `--output-format text|json` — choose non-interactive prompt output rendering
-- `--allowedTools <tool[,tool...]>` — restrict enabled tools for interactive sessions and prompt-mode tool use
-
-### Interactive slash commands
-
-- `/help` — show command help
-- `/status` — show current session status
-- `/compact` — compact local session history
-- `/model [model]` — inspect or switch the active model
-- `/permissions [read-only|workspace-write|danger-full-access]` — inspect or switch permissions
-- `/clear [--confirm]` — clear the current local session
-- `/cost` — show token usage totals
-- `/resume <session-id-or-path>` — load a saved session into the REPL
-- `/config [env|hooks|model]` — inspect discovered Claude config
-- `/memory` — inspect loaded instruction memory files
-- `/init` — bootstrap `.claude.json`, `.claude/`, `CLAUDE.md`, and local ignore rules
-- `/diff` — show the current git diff for the workspace
-- `/version` — print version and build metadata locally
-- `/export [file]` — export the current conversation transcript
-- `/sessions` — list recent managed local sessions from `~/.claude/sessions/`
-- `/session [list|switch <session-id>]` — inspect or switch managed local sessions
-- `/exit` — leave the REPL
-
-## Environment variables
-
-### Anthropic/API
-
-- `ANTHROPIC_API_KEY` — highest-precedence API credential
-- `ANTHROPIC_AUTH_TOKEN` — bearer-token override used when no API key is set
-- Persisted OAuth credentials in `~/.claude/credentials.json` — used when neither env var is set
-- `ANTHROPIC_BASE_URL` — override the Anthropic API base URL
-- `ANTHROPIC_MODEL` — default model used by selected live integration tests
-
-### CLI/runtime
-
-- `RUSTY_CLAUDE_PERMISSION_MODE` — default REPL permission mode (`read-only`, `workspace-write`, or `danger-full-access`)
-- `CLAUDE_CONFIG_HOME` — override Claude config discovery root
-- `CLAUDE_CODE_REMOTE` — enable remote-session bootstrap handling when supported
-- `CLAUDE_CODE_REMOTE_SESSION_ID` — remote session identifier when using remote mode
-- `CLAUDE_CODE_UPSTREAM` — override the upstream TS source path for compat-harness extraction
-- `CLAWD_WEB_SEARCH_BASE_URL` — override the built-in web search service endpoint used by tooling
-
-## Notes
-
-- `compat-harness` exists to compare the Rust port against the upstream TypeScript codebase and is intentionally excluded from the requested release test run.
-- The CLI currently focuses on a practical integrated workflow: prompt execution, REPL operation, session inspection/resume, config discovery, and tool/runtime plumbing.

rust/crates/api/src/error.rs

@@ -4,7 +4,10 @@ use std::time::Duration;
 
 #[derive(Debug)]
 pub enum ApiError {
-    MissingApiKey,
+    MissingCredentials {
+        provider: &'static str,
+        env_vars: &'static [&'static str],
+    },
     ExpiredOAuthToken,
     Auth(String),
     InvalidApiKeyEnv(VarError),
@@ -30,13 +33,21 @@ pub enum ApiError {
 }
 
 impl ApiError {
+    #[must_use]
+    pub const fn missing_credentials(
+        provider: &'static str,
+        env_vars: &'static [&'static str],
+    ) -> Self {
+        Self::MissingCredentials { provider, env_vars }
+    }
+
     #[must_use]
     pub fn is_retryable(&self) -> bool {
         match self {
             Self::Http(error) => error.is_connect() || error.is_timeout() || error.is_request(),
             Self::Api { retryable, .. } => *retryable,
             Self::RetriesExhausted { last_error, .. } => last_error.is_retryable(),
-            Self::MissingApiKey
+            Self::MissingCredentials { .. }
             | Self::ExpiredOAuthToken
             | Self::Auth(_)
             | Self::InvalidApiKeyEnv(_)
@@ -51,12 +62,11 @@ impl ApiError {
 impl Display for ApiError {
     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
         match self {
-            Self::MissingApiKey => {
+            Self::MissingCredentials { provider, env_vars } => write!(
-                write!(
+                f,
-                    f,
+                "missing {provider} credentials; export {} before calling the {provider} API",
-                    "ANTHROPIC_AUTH_TOKEN or ANTHROPIC_API_KEY is not set; export one before calling the Anthropic API"
+                env_vars.join(" or ")
-                )
+            ),
-            }
             Self::ExpiredOAuthToken => {
                 write!(
                     f,
@@ -65,10 +75,7 @@ impl Display for ApiError {
             }
             Self::Auth(message) => write!(f, "auth error: {message}"),
             Self::InvalidApiKeyEnv(error) => {
-                write!(
+                write!(f, "failed to read credential environment variable: {error}")
-                    f,
-                    "failed to read ANTHROPIC_AUTH_TOKEN / ANTHROPIC_API_KEY: {error}"
-                )
             }
             Self::Http(error) => write!(f, "http error: {error}"),
             Self::Io(error) => write!(f, "io error: {error}"),
@@ -81,20 +88,14 @@ impl Display for ApiError {
                 ..
             } => match (error_type, message) {
                 (Some(error_type), Some(message)) => {
-                    write!(
+                    write!(f, "api returned {status} ({error_type}): {message}")
-                        f,
-                        "anthropic api returned {status} ({error_type}): {message}"
-                    )
                 }
-                _ => write!(f, "anthropic api returned {status}: {body}"),
+                _ => write!(f, "api returned {status}: {body}"),
             },
             Self::RetriesExhausted {
                 attempts,
                 last_error,
-            } => write!(
+            } => write!(f, "api failed after {attempts} attempts: {last_error}"),
-                f,
-                "anthropic api failed after {attempts} attempts: {last_error}"
-            ),
             Self::InvalidSseFrame(message) => write!(f, "invalid sse frame: {message}"),
             Self::BackoffOverflow {
                 attempt,

rust/crates/api/src/lib.rs

@@ -1,13 +1,19 @@
 mod client;
 mod error;
+mod providers;
 mod sse;
 mod types;
 
 pub use client::{
-    oauth_token_is_expired, read_base_url, resolve_saved_oauth_token,
+    oauth_token_is_expired, read_base_url, read_xai_base_url, resolve_saved_oauth_token,
-    resolve_startup_auth_source, AnthropicClient, AuthSource, MessageStream, OAuthTokenSet,
+    resolve_startup_auth_source, MessageStream, OAuthTokenSet, ProviderClient,
 };
 pub use error::ApiError;
+pub use providers::anthropic::{AnthropicClient, AuthSource};
+pub use providers::openai_compat::{OpenAiCompatClient, OpenAiCompatConfig};
+pub use providers::{
+    detect_provider_kind, max_tokens_for_model, resolve_model_alias, ProviderKind,
+};
 pub use sse::{parse_frame, SseParser};
 pub use types::{
     ContentBlockDelta, ContentBlockDeltaEvent, ContentBlockStartEvent, ContentBlockStopEvent,

rust/crates/api/src/providers/mod.rs

@@ -0,0 +1,216 @@
+use std::future::Future;
+use std::pin::Pin;
+
+use crate::error::ApiError;
+use crate::types::{MessageRequest, MessageResponse};
+
+pub mod anthropic;
+pub mod openai_compat;
+
+pub type ProviderFuture<'a, T> = Pin<Box<dyn Future<Output = Result<T, ApiError>> + Send + 'a>>;
+
+pub trait Provider {
+    type Stream;
+
+    fn send_message<'a>(
+        &'a self,
+        request: &'a MessageRequest,
+    ) -> ProviderFuture<'a, MessageResponse>;
+
+    fn stream_message<'a>(
+        &'a self,
+        request: &'a MessageRequest,
+    ) -> ProviderFuture<'a, Self::Stream>;
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum ProviderKind {
+    Anthropic,
+    Xai,
+    OpenAi,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub struct ProviderMetadata {
+    pub provider: ProviderKind,
+    pub auth_env: &'static str,
+    pub base_url_env: &'static str,
+    pub default_base_url: &'static str,
+}
+
+const MODEL_REGISTRY: &[(&str, ProviderMetadata)] = &[
+    (
+        "opus",
+        ProviderMetadata {
+            provider: ProviderKind::Anthropic,
+            auth_env: "ANTHROPIC_API_KEY",
+            base_url_env: "ANTHROPIC_BASE_URL",
+            default_base_url: anthropic::DEFAULT_BASE_URL,
+        },
+    ),
+    (
+        "sonnet",
+        ProviderMetadata {
+            provider: ProviderKind::Anthropic,
+            auth_env: "ANTHROPIC_API_KEY",
+            base_url_env: "ANTHROPIC_BASE_URL",
+            default_base_url: anthropic::DEFAULT_BASE_URL,
+        },
+    ),
+    (
+        "haiku",
+        ProviderMetadata {
+            provider: ProviderKind::Anthropic,
+            auth_env: "ANTHROPIC_API_KEY",
+            base_url_env: "ANTHROPIC_BASE_URL",
+            default_base_url: anthropic::DEFAULT_BASE_URL,
+        },
+    ),
+    (
+        "grok",
+        ProviderMetadata {
+            provider: ProviderKind::Xai,
+            auth_env: "XAI_API_KEY",
+            base_url_env: "XAI_BASE_URL",
+            default_base_url: openai_compat::DEFAULT_XAI_BASE_URL,
+        },
+    ),
+    (
+        "grok-3",
+        ProviderMetadata {
+            provider: ProviderKind::Xai,
+            auth_env: "XAI_API_KEY",
+            base_url_env: "XAI_BASE_URL",
+            default_base_url: openai_compat::DEFAULT_XAI_BASE_URL,
+        },
+    ),
+    (
+        "grok-mini",
+        ProviderMetadata {
+            provider: ProviderKind::Xai,
+            auth_env: "XAI_API_KEY",
+            base_url_env: "XAI_BASE_URL",
+            default_base_url: openai_compat::DEFAULT_XAI_BASE_URL,
+        },
+    ),
+    (
+        "grok-3-mini",
+        ProviderMetadata {
+            provider: ProviderKind::Xai,
+            auth_env: "XAI_API_KEY",
+            base_url_env: "XAI_BASE_URL",
+            default_base_url: openai_compat::DEFAULT_XAI_BASE_URL,
+        },
+    ),
+    (
+        "grok-2",
+        ProviderMetadata {
+            provider: ProviderKind::Xai,
+            auth_env: "XAI_API_KEY",
+            base_url_env: "XAI_BASE_URL",
+            default_base_url: openai_compat::DEFAULT_XAI_BASE_URL,
+        },
+    ),
+];
+
+#[must_use]
+pub fn resolve_model_alias(model: &str) -> String {
+    let trimmed = model.trim();
+    let lower = trimmed.to_ascii_lowercase();
+    MODEL_REGISTRY
+        .iter()
+        .find_map(|(alias, metadata)| {
+            (*alias == lower).then_some(match metadata.provider {
+                ProviderKind::Anthropic => match *alias {
+                    "opus" => "claude-opus-4-6",
+                    "sonnet" => "claude-sonnet-4-6",
+                    "haiku" => "claude-haiku-4-5-20251213",
+                    _ => trimmed,
+                },
+                ProviderKind::Xai => match *alias {
+                    "grok" | "grok-3" => "grok-3",
+                    "grok-mini" | "grok-3-mini" => "grok-3-mini",
+                    "grok-2" => "grok-2",
+                    _ => trimmed,
+                },
+                ProviderKind::OpenAi => trimmed,
+            })
+        })
+        .map_or_else(|| trimmed.to_string(), ToOwned::to_owned)
+}
+
+#[must_use]
+pub fn metadata_for_model(model: &str) -> Option<ProviderMetadata> {
+    let canonical = resolve_model_alias(model);
+    if canonical.starts_with("claude") {
+        return Some(ProviderMetadata {
+            provider: ProviderKind::Anthropic,
+            auth_env: "ANTHROPIC_API_KEY",
+            base_url_env: "ANTHROPIC_BASE_URL",
+            default_base_url: anthropic::DEFAULT_BASE_URL,
+        });
+    }
+    if canonical.starts_with("grok") {
+        return Some(ProviderMetadata {
+            provider: ProviderKind::Xai,
+            auth_env: "XAI_API_KEY",
+            base_url_env: "XAI_BASE_URL",
+            default_base_url: openai_compat::DEFAULT_XAI_BASE_URL,
+        });
+    }
+    None
+}
+
+#[must_use]
+pub fn detect_provider_kind(model: &str) -> ProviderKind {
+    if let Some(metadata) = metadata_for_model(model) {
+        return metadata.provider;
+    }
+    if anthropic::has_auth_from_env_or_saved().unwrap_or(false) {
+        return ProviderKind::Anthropic;
+    }
+    if openai_compat::has_api_key("OPENAI_API_KEY") {
+        return ProviderKind::OpenAi;
+    }
+    if openai_compat::has_api_key("XAI_API_KEY") {
+        return ProviderKind::Xai;
+    }
+    ProviderKind::Anthropic
+}
+
+#[must_use]
+pub fn max_tokens_for_model(model: &str) -> u32 {
+    let canonical = resolve_model_alias(model);
+    if canonical.contains("opus") {
+        32_000
+    } else {
+        64_000
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{detect_provider_kind, max_tokens_for_model, resolve_model_alias, ProviderKind};
+
+    #[test]
+    fn resolves_grok_aliases() {
+        assert_eq!(resolve_model_alias("grok"), "grok-3");
+        assert_eq!(resolve_model_alias("grok-mini"), "grok-3-mini");
+        assert_eq!(resolve_model_alias("grok-2"), "grok-2");
+    }
+
+    #[test]
+    fn detects_provider_from_model_name_first() {
+        assert_eq!(detect_provider_kind("grok"), ProviderKind::Xai);
+        assert_eq!(
+            detect_provider_kind("claude-sonnet-4-6"),
+            ProviderKind::Anthropic
+        );
+    }
+
+    #[test]
+    fn keeps_existing_max_token_heuristic() {
+        assert_eq!(max_tokens_for_model("opus"), 32_000);
+        assert_eq!(max_tokens_for_model("grok-3"), 64_000);
+    }
+}

rust/crates/api/tests/client_integration.rs

@@ -3,9 +3,9 @@ use std::sync::Arc;
 use std::time::Duration;
 
 use api::{
-    AnthropicClient, ApiError, ContentBlockDelta, ContentBlockDeltaEvent, ContentBlockStartEvent,
+    AnthropicClient, ApiError, AuthSource, ContentBlockDelta, ContentBlockDeltaEvent,
-    InputContentBlock, InputMessage, MessageDeltaEvent, MessageRequest, OutputContentBlock,
+    ContentBlockStartEvent, InputContentBlock, InputMessage, MessageDeltaEvent, MessageRequest,
-    StreamEvent, ToolChoice, ToolDefinition,
+    OutputContentBlock, ProviderClient, StreamEvent, ToolChoice, ToolDefinition,
 };
 use serde_json::json;
 use tokio::io::{AsyncReadExt, AsyncWriteExt};
@@ -195,6 +195,47 @@ async fn retries_retryable_failures_before_succeeding() {
     assert_eq!(state.lock().await.len(), 2);
 }
 
+#[tokio::test]
+async fn provider_client_dispatches_anthropic_requests() {
+    let state = Arc::new(Mutex::new(Vec::<CapturedRequest>::new()));
+    let server = spawn_server(
+        state.clone(),
+        vec![http_response(
+            "200 OK",
+            "application/json",
+            "{\"id\":\"msg_provider\",\"type\":\"message\",\"role\":\"assistant\",\"content\":[{\"type\":\"text\",\"text\":\"Dispatched\"}],\"model\":\"claude-3-7-sonnet-latest\",\"stop_reason\":\"end_turn\",\"stop_sequence\":null,\"usage\":{\"input_tokens\":3,\"output_tokens\":2}}",
+        )],
+    )
+    .await;
+
+    let client = ProviderClient::from_model_with_anthropic_auth(
+        "claude-sonnet-4-6",
+        Some(AuthSource::ApiKey("test-key".to_string())),
+    )
+    .expect("anthropic provider client should be constructed");
+    let client = match client {
+        ProviderClient::Anthropic(client) => {
+            ProviderClient::Anthropic(client.with_base_url(server.base_url()))
+        }
+        other => panic!("expected anthropic provider, got {other:?}"),
+    };
+
+    let response = client
+        .send_message(&sample_request(false))
+        .await
+        .expect("provider-dispatched request should succeed");
+
+    assert_eq!(response.total_tokens(), 5);
+
+    let captured = state.lock().await;
+    let request = captured.first().expect("server should capture request");
+    assert_eq!(request.path, "/v1/messages");
+    assert_eq!(
+        request.headers.get("x-api-key").map(String::as_str),
+        Some("test-key")
+    );
+}
+
 #[tokio::test]
 async fn surfaces_retry_exhaustion_for_persistent_retryable_errors() {
     let state = Arc::new(Mutex::new(Vec::<CapturedRequest>::new()));

rust/crates/api/tests/openai_compat_integration.rs

@@ -0,0 +1,415 @@
+use std::collections::HashMap;
+use std::ffi::OsString;
+use std::sync::Arc;
+use std::sync::{Mutex as StdMutex, OnceLock};
+
+use api::{
+    ContentBlockDelta, ContentBlockDeltaEvent, ContentBlockStartEvent, ContentBlockStopEvent,
+    InputContentBlock, InputMessage, MessageRequest, OpenAiCompatClient, OpenAiCompatConfig,
+    OutputContentBlock, ProviderClient, StreamEvent, ToolChoice, ToolDefinition,
+};
+use serde_json::json;
+use tokio::io::{AsyncReadExt, AsyncWriteExt};
+use tokio::net::TcpListener;
+use tokio::sync::Mutex;
+
+#[tokio::test]
+async fn send_message_uses_openai_compatible_endpoint_and_auth() {
+    let state = Arc::new(Mutex::new(Vec::<CapturedRequest>::new()));
+    let body = concat!(
+        "{",
+        "\"id\":\"chatcmpl_test\",",
+        "\"model\":\"grok-3\",",
+        "\"choices\":[{",
+        "\"message\":{\"role\":\"assistant\",\"content\":\"Hello from Grok\",\"tool_calls\":[]},",
+        "\"finish_reason\":\"stop\"",
+        "}],",
+        "\"usage\":{\"prompt_tokens\":11,\"completion_tokens\":5}",
+        "}"
+    );
+    let server = spawn_server(
+        state.clone(),
+        vec![http_response("200 OK", "application/json", body)],
+    )
+    .await;
+
+    let client = OpenAiCompatClient::new("xai-test-key", OpenAiCompatConfig::xai())
+        .with_base_url(server.base_url());
+    let response = client
+        .send_message(&sample_request(false))
+        .await
+        .expect("request should succeed");
+
+    assert_eq!(response.model, "grok-3");
+    assert_eq!(response.total_tokens(), 16);
+    assert_eq!(
+        response.content,
+        vec![OutputContentBlock::Text {
+            text: "Hello from Grok".to_string(),
+        }]
+    );
+
+    let captured = state.lock().await;
+    let request = captured.first().expect("server should capture request");
+    assert_eq!(request.path, "/chat/completions");
+    assert_eq!(
+        request.headers.get("authorization").map(String::as_str),
+        Some("Bearer xai-test-key")
+    );
+    let body: serde_json::Value = serde_json::from_str(&request.body).expect("json body");
+    assert_eq!(body["model"], json!("grok-3"));
+    assert_eq!(body["messages"][0]["role"], json!("system"));
+    assert_eq!(body["tools"][0]["type"], json!("function"));
+}
+
+#[tokio::test]
+async fn send_message_accepts_full_chat_completions_endpoint_override() {
+    let state = Arc::new(Mutex::new(Vec::<CapturedRequest>::new()));
+    let body = concat!(
+        "{",
+        "\"id\":\"chatcmpl_full_endpoint\",",
+        "\"model\":\"grok-3\",",
+        "\"choices\":[{",
+        "\"message\":{\"role\":\"assistant\",\"content\":\"Endpoint override works\",\"tool_calls\":[]},",
+        "\"finish_reason\":\"stop\"",
+        "}],",
+        "\"usage\":{\"prompt_tokens\":7,\"completion_tokens\":3}",
+        "}"
+    );
+    let server = spawn_server(
+        state.clone(),
+        vec![http_response("200 OK", "application/json", body)],
+    )
+    .await;
+
+    let endpoint_url = format!("{}/chat/completions", server.base_url());
+    let client = OpenAiCompatClient::new("xai-test-key", OpenAiCompatConfig::xai())
+        .with_base_url(endpoint_url);
+    let response = client
+        .send_message(&sample_request(false))
+        .await
+        .expect("request should succeed");
+
+    assert_eq!(response.total_tokens(), 10);
+
+    let captured = state.lock().await;
+    let request = captured.first().expect("server should capture request");
+    assert_eq!(request.path, "/chat/completions");
+}
+
+#[tokio::test]
+async fn stream_message_normalizes_text_and_multiple_tool_calls() {
+    let state = Arc::new(Mutex::new(Vec::<CapturedRequest>::new()));
+    let sse = concat!(
+        "data: {\"id\":\"chatcmpl_stream\",\"model\":\"grok-3\",\"choices\":[{\"delta\":{\"content\":\"Hello\"}}]}\n\n",
+        "data: {\"id\":\"chatcmpl_stream\",\"choices\":[{\"delta\":{\"tool_calls\":[{\"index\":0,\"id\":\"call_1\",\"function\":{\"name\":\"weather\",\"arguments\":\"{\\\"city\\\":\\\"Paris\\\"}\"}},{\"index\":1,\"id\":\"call_2\",\"function\":{\"name\":\"clock\",\"arguments\":\"{\\\"zone\\\":\\\"UTC\\\"}\"}}]}}]}\n\n",
+        "data: {\"id\":\"chatcmpl_stream\",\"choices\":[{\"delta\":{},\"finish_reason\":\"tool_calls\"}]}\n\n",
+        "data: [DONE]\n\n"
+    );
+    let server = spawn_server(
+        state.clone(),
+        vec![http_response_with_headers(
+            "200 OK",
+            "text/event-stream",
+            sse,
+            &[("x-request-id", "req_grok_stream")],
+        )],
+    )
+    .await;
+
+    let client = OpenAiCompatClient::new("xai-test-key", OpenAiCompatConfig::xai())
+        .with_base_url(server.base_url());
+    let mut stream = client
+        .stream_message(&sample_request(false))
+        .await
+        .expect("stream should start");
+
+    assert_eq!(stream.request_id(), Some("req_grok_stream"));
+
+    let mut events = Vec::new();
+    while let Some(event) = stream.next_event().await.expect("event should parse") {
+        events.push(event);
+    }
+
+    assert!(matches!(events[0], StreamEvent::MessageStart(_)));
+    assert!(matches!(
+        events[1],
+        StreamEvent::ContentBlockStart(ContentBlockStartEvent {
+            content_block: OutputContentBlock::Text { .. },
+            ..
+        })
+    ));
+    assert!(matches!(
+        events[2],
+        StreamEvent::ContentBlockDelta(ContentBlockDeltaEvent {
+            delta: ContentBlockDelta::TextDelta { .. },
+            ..
+        })
+    ));
+    assert!(matches!(
+        events[3],
+        StreamEvent::ContentBlockStart(ContentBlockStartEvent {
+            index: 1,
+            content_block: OutputContentBlock::ToolUse { .. },
+        })
+    ));
+    assert!(matches!(
+        events[4],
+        StreamEvent::ContentBlockDelta(ContentBlockDeltaEvent {
+            index: 1,
+            delta: ContentBlockDelta::InputJsonDelta { .. },
+        })
+    ));
+    assert!(matches!(
+        events[5],
+        StreamEvent::ContentBlockStart(ContentBlockStartEvent {
+            index: 2,
+            content_block: OutputContentBlock::ToolUse { .. },
+        })
+    ));
+    assert!(matches!(
+        events[6],
+        StreamEvent::ContentBlockDelta(ContentBlockDeltaEvent {
+            index: 2,
+            delta: ContentBlockDelta::InputJsonDelta { .. },
+        })
+    ));
+    assert!(matches!(
+        events[7],
+        StreamEvent::ContentBlockStop(ContentBlockStopEvent { index: 1 })
+    ));
+    assert!(matches!(
+        events[8],
+        StreamEvent::ContentBlockStop(ContentBlockStopEvent { index: 2 })
+    ));
+    assert!(matches!(
+        events[9],
+        StreamEvent::ContentBlockStop(ContentBlockStopEvent { index: 0 })
+    ));
+    assert!(matches!(events[10], StreamEvent::MessageDelta(_)));
+    assert!(matches!(events[11], StreamEvent::MessageStop(_)));
+
+    let captured = state.lock().await;
+    let request = captured.first().expect("captured request");
+    assert_eq!(request.path, "/chat/completions");
+    assert!(request.body.contains("\"stream\":true"));
+}
+
+#[tokio::test]
+async fn provider_client_dispatches_xai_requests_from_env() {
+    let _lock = env_lock();
+    let _api_key = ScopedEnvVar::set("XAI_API_KEY", "xai-test-key");
+
+    let state = Arc::new(Mutex::new(Vec::<CapturedRequest>::new()));
+    let server = spawn_server(
+        state.clone(),
+        vec![http_response(
+            "200 OK",
+            "application/json",
+            "{\"id\":\"chatcmpl_provider\",\"model\":\"grok-3\",\"choices\":[{\"message\":{\"role\":\"assistant\",\"content\":\"Through provider client\",\"tool_calls\":[]},\"finish_reason\":\"stop\"}],\"usage\":{\"prompt_tokens\":9,\"completion_tokens\":4}}",
+        )],
+    )
+    .await;
+    let _base_url = ScopedEnvVar::set("XAI_BASE_URL", server.base_url());
+
+    let client =
+        ProviderClient::from_model("grok").expect("xAI provider client should be constructed");
+    assert!(matches!(client, ProviderClient::Xai(_)));
+
+    let response = client
+        .send_message(&sample_request(false))
+        .await
+        .expect("provider-dispatched request should succeed");
+
+    assert_eq!(response.total_tokens(), 13);
+
+    let captured = state.lock().await;
+    let request = captured.first().expect("captured request");
+    assert_eq!(request.path, "/chat/completions");
+    assert_eq!(
+        request.headers.get("authorization").map(String::as_str),
+        Some("Bearer xai-test-key")
+    );
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+struct CapturedRequest {
+    path: String,
+    headers: HashMap<String, String>,
+    body: String,
+}
+
+struct TestServer {
+    base_url: String,
+    join_handle: tokio::task::JoinHandle<()>,
+}
+
+impl TestServer {
+    fn base_url(&self) -> String {
+        self.base_url.clone()
+    }
+}
+
+impl Drop for TestServer {
+    fn drop(&mut self) {
+        self.join_handle.abort();
+    }
+}
+
+async fn spawn_server(
+    state: Arc<Mutex<Vec<CapturedRequest>>>,
+    responses: Vec<String>,
+) -> TestServer {
+    let listener = TcpListener::bind("127.0.0.1:0")
+        .await
+        .expect("listener should bind");
+    let address = listener.local_addr().expect("listener addr");
+    let join_handle = tokio::spawn(async move {
+        for response in responses {
+            let (mut socket, _) = listener.accept().await.expect("accept");
+            let mut buffer = Vec::new();
+            let mut header_end = None;
+            loop {
+                let mut chunk = [0_u8; 1024];
+                let read = socket.read(&mut chunk).await.expect("read request");
+                if read == 0 {
+                    break;
+                }
+                buffer.extend_from_slice(&chunk[..read]);
+                if let Some(position) = find_header_end(&buffer) {
+                    header_end = Some(position);
+                    break;
+                }
+            }
+
+            let header_end = header_end.expect("headers should exist");
+            let (header_bytes, remaining) = buffer.split_at(header_end);
+            let header_text = String::from_utf8(header_bytes.to_vec()).expect("utf8 headers");
+            let mut lines = header_text.split("\r\n");
+            let request_line = lines.next().expect("request line");
+            let path = request_line
+                .split_whitespace()
+                .nth(1)
+                .expect("path")
+                .to_string();
+            let mut headers = HashMap::new();
+            let mut content_length = 0_usize;
+            for line in lines {
+                if line.is_empty() {
+                    continue;
+                }
+                let (name, value) = line.split_once(':').expect("header");
+                let value = value.trim().to_string();
+                if name.eq_ignore_ascii_case("content-length") {
+                    content_length = value.parse().expect("content length");
+                }
+                headers.insert(name.to_ascii_lowercase(), value);
+            }
+
+            let mut body = remaining[4..].to_vec();
+            while body.len() < content_length {
+                let mut chunk = vec![0_u8; content_length - body.len()];
+                let read = socket.read(&mut chunk).await.expect("read body");
+                if read == 0 {
+                    break;
+                }
+                body.extend_from_slice(&chunk[..read]);
+            }
+
+            state.lock().await.push(CapturedRequest {
+                path,
+                headers,
+                body: String::from_utf8(body).expect("utf8 body"),
+            });
+
+            socket
+                .write_all(response.as_bytes())
+                .await
+                .expect("write response");
+        }
+    });
+
+    TestServer {
+        base_url: format!("http://{address}"),
+        join_handle,
+    }
+}
+
+fn find_header_end(bytes: &[u8]) -> Option<usize> {
+    bytes.windows(4).position(|window| window == b"\r\n\r\n")
+}
+
+fn http_response(status: &str, content_type: &str, body: &str) -> String {
+    http_response_with_headers(status, content_type, body, &[])
+}
+
+fn http_response_with_headers(
+    status: &str,
+    content_type: &str,
+    body: &str,
+    headers: &[(&str, &str)],
+) -> String {
+    let mut extra_headers = String::new();
+    for (name, value) in headers {
+        use std::fmt::Write as _;
+        write!(&mut extra_headers, "{name}: {value}\r\n").expect("header write");
+    }
+    format!(
+        "HTTP/1.1 {status}\r\ncontent-type: {content_type}\r\n{extra_headers}content-length: {}\r\nconnection: close\r\n\r\n{body}",
+        body.len()
+    )
+}
+
+fn sample_request(stream: bool) -> MessageRequest {
+    MessageRequest {
+        model: "grok-3".to_string(),
+        max_tokens: 64,
+        messages: vec![InputMessage {
+            role: "user".to_string(),
+            content: vec![InputContentBlock::Text {
+                text: "Say hello".to_string(),
+            }],
+        }],
+        system: Some("Use tools when needed".to_string()),
+        tools: Some(vec![ToolDefinition {
+            name: "weather".to_string(),
+            description: Some("Fetches weather".to_string()),
+            input_schema: json!({
+                "type": "object",
+                "properties": {"city": {"type": "string"}},
+                "required": ["city"]
+            }),
+        }]),
+        tool_choice: Some(ToolChoice::Auto),
+        stream,
+    }
+}
+
+fn env_lock() -> std::sync::MutexGuard<'static, ()> {
+    static LOCK: OnceLock<StdMutex<()>> = OnceLock::new();
+    LOCK.get_or_init(|| StdMutex::new(()))
+        .lock()
+        .unwrap_or_else(|poisoned| poisoned.into_inner())
+}
+
+struct ScopedEnvVar {
+    key: &'static str,
+    previous: Option<OsString>,
+}
+
+impl ScopedEnvVar {
+    fn set(key: &'static str, value: impl AsRef<std::ffi::OsStr>) -> Self {
+        let previous = std::env::var_os(key);
+        std::env::set_var(key, value);
+        Self { key, previous }
+    }
+}
+
+impl Drop for ScopedEnvVar {
+    fn drop(&mut self) {
+        match &self.previous {
+            Some(value) => std::env::set_var(self.key, value),
+            None => std::env::remove_var(self.key),
+        }
+    }
+}

rust/crates/api/tests/provider_client_integration.rs

@@ -0,0 +1,86 @@
+use std::ffi::OsString;
+use std::sync::{Mutex, OnceLock};
+
+use api::{read_xai_base_url, ApiError, AuthSource, ProviderClient, ProviderKind};
+
+#[test]
+fn provider_client_routes_grok_aliases_through_xai() {
+    let _lock = env_lock();
+    let _xai_api_key = EnvVarGuard::set("XAI_API_KEY", Some("xai-test-key"));
+
+    let client = ProviderClient::from_model("grok-mini").expect("grok alias should resolve");
+
+    assert_eq!(client.provider_kind(), ProviderKind::Xai);
+}
+
+#[test]
+fn provider_client_reports_missing_xai_credentials_for_grok_models() {
+    let _lock = env_lock();
+    let _xai_api_key = EnvVarGuard::set("XAI_API_KEY", None);
+
+    let error = ProviderClient::from_model("grok-3")
+        .expect_err("grok requests without XAI_API_KEY should fail fast");
+
+    match error {
+        ApiError::MissingCredentials { provider, env_vars } => {
+            assert_eq!(provider, "xAI");
+            assert_eq!(env_vars, &["XAI_API_KEY"]);
+        }
+        other => panic!("expected missing xAI credentials, got {other:?}"),
+    }
+}
+
+#[test]
+fn provider_client_uses_explicit_anthropic_auth_without_env_lookup() {
+    let _lock = env_lock();
+    let _anthropic_api_key = EnvVarGuard::set("ANTHROPIC_API_KEY", None);
+    let _anthropic_auth_token = EnvVarGuard::set("ANTHROPIC_AUTH_TOKEN", None);
+
+    let client = ProviderClient::from_model_with_anthropic_auth(
+        "claude-sonnet-4-6",
+        Some(AuthSource::ApiKey("anthropic-test-key".to_string())),
+    )
+    .expect("explicit anthropic auth should avoid env lookup");
+
+    assert_eq!(client.provider_kind(), ProviderKind::Anthropic);
+}
+
+#[test]
+fn read_xai_base_url_prefers_env_override() {
+    let _lock = env_lock();
+    let _xai_base_url = EnvVarGuard::set("XAI_BASE_URL", Some("https://example.xai.test/v1"));
+
+    assert_eq!(read_xai_base_url(), "https://example.xai.test/v1");
+}
+
+fn env_lock() -> std::sync::MutexGuard<'static, ()> {
+    static LOCK: OnceLock<Mutex<()>> = OnceLock::new();
+    LOCK.get_or_init(|| Mutex::new(()))
+        .lock()
+        .unwrap_or_else(|poisoned| poisoned.into_inner())
+}
+
+struct EnvVarGuard {
+    key: &'static str,
+    original: Option<OsString>,
+}
+
+impl EnvVarGuard {
+    fn set(key: &'static str, value: Option<&str>) -> Self {
+        let original = std::env::var_os(key);
+        match value {
+            Some(value) => std::env::set_var(key, value),
+            None => std::env::remove_var(key),
+        }
+        Self { key, original }
+    }
+}
+
+impl Drop for EnvVarGuard {
+    fn drop(&mut self) {
+        match &self.original {
+            Some(value) => std::env::set_var(self.key, value),
+            None => std::env::remove_var(self.key),
+        }
+    }
+}

rust/crates/runtime/src/config.rs

@@ -37,6 +37,7 @@ pub struct RuntimeConfig {
 
 #[derive(Debug, Clone, PartialEq, Eq, Default)]
 pub struct RuntimeFeatureConfig {
+    hooks: RuntimeHookConfig,
     mcp: McpConfigCollection,
     oauth: Option<OAuthConfig>,
     model: Option<String>,
@@ -44,6 +45,12 @@ pub struct RuntimeFeatureConfig {
     sandbox: SandboxConfig,
 }
 
+#[derive(Debug, Clone, PartialEq, Eq, Default)]
+pub struct RuntimeHookConfig {
+    pre_tool_use: Vec<String>,
+    post_tool_use: Vec<String>,
+}
+
 #[derive(Debug, Clone, PartialEq, Eq, Default)]
 pub struct McpConfigCollection {
     servers: BTreeMap<String, ScopedMcpServerConfig>,
@@ -221,6 +228,7 @@ impl ConfigLoader {
         let merged_value = JsonValue::Object(merged.clone());
 
         let feature_config = RuntimeFeatureConfig {
+            hooks: parse_optional_hooks_config(&merged_value)?,
             mcp: McpConfigCollection {
                 servers: mcp_servers,
             },
@@ -278,6 +286,11 @@ impl RuntimeConfig {
         &self.feature_config.mcp
     }
 
+    #[must_use]
+    pub fn hooks(&self) -> &RuntimeHookConfig {
+        &self.feature_config.hooks
+    }
+
     #[must_use]
     pub fn oauth(&self) -> Option<&OAuthConfig> {
         self.feature_config.oauth.as_ref()
@@ -300,6 +313,17 @@ impl RuntimeConfig {
 }
 
 impl RuntimeFeatureConfig {
+    #[must_use]
+    pub fn with_hooks(mut self, hooks: RuntimeHookConfig) -> Self {
+        self.hooks = hooks;
+        self
+    }
+
+    #[must_use]
+    pub fn hooks(&self) -> &RuntimeHookConfig {
+        &self.hooks
+    }
+
     #[must_use]
     pub fn mcp(&self) -> &McpConfigCollection {
         &self.mcp
@@ -326,6 +350,26 @@ impl RuntimeFeatureConfig {
     }
 }
 
+impl RuntimeHookConfig {
+    #[must_use]
+    pub fn new(pre_tool_use: Vec<String>, post_tool_use: Vec<String>) -> Self {
+        Self {
+            pre_tool_use,
+            post_tool_use,
+        }
+    }
+
+    #[must_use]
+    pub fn pre_tool_use(&self) -> &[String] {
+        &self.pre_tool_use
+    }
+
+    #[must_use]
+    pub fn post_tool_use(&self) -> &[String] {
+        &self.post_tool_use
+    }
+}
+
 impl McpConfigCollection {
     #[must_use]
     pub fn servers(&self) -> &BTreeMap<String, ScopedMcpServerConfig> {
@@ -424,6 +468,22 @@ fn parse_optional_model(root: &JsonValue) -> Option<String> {
         .map(ToOwned::to_owned)
 }
 
+fn parse_optional_hooks_config(root: &JsonValue) -> Result<RuntimeHookConfig, ConfigError> {
+    let Some(object) = root.as_object() else {
+        return Ok(RuntimeHookConfig::default());
+    };
+    let Some(hooks_value) = object.get("hooks") else {
+        return Ok(RuntimeHookConfig::default());
+    };
+    let hooks = expect_object(hooks_value, "merged settings.hooks")?;
+    Ok(RuntimeHookConfig {
+        pre_tool_use: optional_string_array(hooks, "PreToolUse", "merged settings.hooks")?
+            .unwrap_or_default(),
+        post_tool_use: optional_string_array(hooks, "PostToolUse", "merged settings.hooks")?
+            .unwrap_or_default(),
+    })
+}
+
 fn parse_optional_permission_mode(
     root: &JsonValue,
 ) -> Result<Option<ResolvedPermissionMode>, ConfigError> {
@@ -836,6 +896,8 @@ mod tests {
             .and_then(JsonValue::as_object)
             .expect("hooks object")
             .contains_key("PostToolUse"));
+        assert_eq!(loaded.hooks().pre_tool_use(), &["base".to_string()]);
+        assert_eq!(loaded.hooks().post_tool_use(), &["project".to_string()]);
         assert!(loaded.mcp().get("home").is_some());
         assert!(loaded.mcp().get("project").is_some());
 

rust/crates/runtime/src/conversation.rs

@@ -4,6 +4,8 @@ use std::fmt::{Display, Formatter};
 use crate::compact::{
     compact_session, estimate_session_tokens, CompactionConfig, CompactionResult,
 };
+use crate::config::RuntimeFeatureConfig;
+use crate::hooks::{HookRunResult, HookRunner};
 use crate::permissions::{PermissionOutcome, PermissionPolicy, PermissionPrompter};
 use crate::session::{ContentBlock, ConversationMessage, Session};
 use crate::usage::{TokenUsage, UsageTracker};
@@ -94,6 +96,7 @@ pub struct ConversationRuntime<C, T> {
     system_prompt: Vec<String>,
     max_iterations: usize,
     usage_tracker: UsageTracker,
+    hook_runner: HookRunner,
 }
 
 impl<C, T> ConversationRuntime<C, T>
@@ -108,6 +111,25 @@ where
         tool_executor: T,
         permission_policy: PermissionPolicy,
         system_prompt: Vec<String>,
+    ) -> Self {
+        Self::new_with_features(
+            session,
+            api_client,
+            tool_executor,
+            permission_policy,
+            system_prompt,
+            &RuntimeFeatureConfig::default(),
+        )
+    }
+
+    #[must_use]
+    pub fn new_with_features(
+        session: Session,
+        api_client: C,
+        tool_executor: T,
+        permission_policy: PermissionPolicy,
+        system_prompt: Vec<String>,
+        feature_config: &RuntimeFeatureConfig,
     ) -> Self {
         let usage_tracker = UsageTracker::from_session(&session);
         Self {
@@ -118,6 +140,7 @@ where
             system_prompt,
             max_iterations: usize::MAX,
             usage_tracker,
+            hook_runner: HookRunner::from_feature_config(feature_config),
         }
     }
 
@@ -185,19 +208,41 @@ where
 
                 let result_message = match permission_outcome {
                     PermissionOutcome::Allow => {
-                        match self.tool_executor.execute(&tool_name, &input) {
+                        let pre_hook_result = self.hook_runner.run_pre_tool_use(&tool_name, &input);
-                            Ok(output) => ConversationMessage::tool_result(
+                        if pre_hook_result.is_denied() {
+                            let deny_message = format!("PreToolUse hook denied tool `{tool_name}`");
+                            ConversationMessage::tool_result(
+                                tool_use_id,
+                                tool_name,
+                                format_hook_message(&pre_hook_result, &deny_message),
+                                true,
+                            )
+                        } else {
+                            let (mut output, mut is_error) =
+                                match self.tool_executor.execute(&tool_name, &input) {
+                                    Ok(output) => (output, false),
+                                    Err(error) => (error.to_string(), true),
+                                };
+                            output = merge_hook_feedback(pre_hook_result.messages(), output, false);
+
+                            let post_hook_result = self
+                                .hook_runner
+                                .run_post_tool_use(&tool_name, &input, &output, is_error);
+                            if post_hook_result.is_denied() {
+                                is_error = true;
+                            }
+                            output = merge_hook_feedback(
+                                post_hook_result.messages(),
+                                output,
+                                post_hook_result.is_denied(),
+                            );
+
+                            ConversationMessage::tool_result(
                                 tool_use_id,
                                 tool_name,
                                 output,
-                                false,
+                                is_error,
-                            ),
+                            )
-                            Err(error) => ConversationMessage::tool_result(
-                                tool_use_id,
-                                tool_name,
-                                error.to_string(),
-                                true,
-                            ),
                         }
                     }
                     PermissionOutcome::Deny { reason } => {
@@ -290,6 +335,32 @@ fn flush_text_block(text: &mut String, blocks: &mut Vec<ContentBlock>) {
     }
 }
 
+fn format_hook_message(result: &HookRunResult, fallback: &str) -> String {
+    if result.messages().is_empty() {
+        fallback.to_string()
+    } else {
+        result.messages().join("\n")
+    }
+}
+
+fn merge_hook_feedback(messages: &[String], output: String, denied: bool) -> String {
+    if messages.is_empty() {
+        return output;
+    }
+
+    let mut sections = Vec::new();
+    if !output.trim().is_empty() {
+        sections.push(output);
+    }
+    let label = if denied {
+        "Hook feedback (denied)"
+    } else {
+        "Hook feedback"
+    };
+    sections.push(format!("{label}:\n{}", messages.join("\n")));
+    sections.join("\n\n")
+}
+
 type ToolHandler = Box<dyn FnMut(&str) -> Result<String, ToolError>>;
 
 #[derive(Default)]
@@ -329,6 +400,7 @@ mod tests {
         StaticToolExecutor,
     };
     use crate::compact::CompactionConfig;
+    use crate::config::{RuntimeFeatureConfig, RuntimeHookConfig};
     use crate::permissions::{
         PermissionMode, PermissionPolicy, PermissionPromptDecision, PermissionPrompter,
         PermissionRequest,
@@ -503,6 +575,141 @@ mod tests {
         ));
     }
 
+    #[test]
+    fn denies_tool_use_when_pre_tool_hook_blocks() {
+        struct SingleCallApiClient;
+        impl ApiClient for SingleCallApiClient {
+            fn stream(&mut self, request: ApiRequest) -> Result<Vec<AssistantEvent>, RuntimeError> {
+                if request
+                    .messages
+                    .iter()
+                    .any(|message| message.role == MessageRole::Tool)
+                {
+                    return Ok(vec![
+                        AssistantEvent::TextDelta("blocked".to_string()),
+                        AssistantEvent::MessageStop,
+                    ]);
+                }
+                Ok(vec![
+                    AssistantEvent::ToolUse {
+                        id: "tool-1".to_string(),
+                        name: "blocked".to_string(),
+                        input: r#"{"path":"secret.txt"}"#.to_string(),
+                    },
+                    AssistantEvent::MessageStop,
+                ])
+            }
+        }
+
+        let mut runtime = ConversationRuntime::new_with_features(
+            Session::new(),
+            SingleCallApiClient,
+            StaticToolExecutor::new().register("blocked", |_input| {
+                panic!("tool should not execute when hook denies")
+            }),
+            PermissionPolicy::new(PermissionMode::DangerFullAccess),
+            vec!["system".to_string()],
+            &RuntimeFeatureConfig::default().with_hooks(RuntimeHookConfig::new(
+                vec![shell_snippet("printf 'blocked by hook'; exit 2")],
+                Vec::new(),
+            )),
+        );
+
+        let summary = runtime
+            .run_turn("use the tool", None)
+            .expect("conversation should continue after hook denial");
+
+        assert_eq!(summary.tool_results.len(), 1);
+        let ContentBlock::ToolResult {
+            is_error, output, ..
+        } = &summary.tool_results[0].blocks[0]
+        else {
+            panic!("expected tool result block");
+        };
+        assert!(
+            *is_error,
+            "hook denial should produce an error result: {output}"
+        );
+        assert!(
+            output.contains("denied tool") || output.contains("blocked by hook"),
+            "unexpected hook denial output: {output:?}"
+        );
+    }
+
+    #[test]
+    fn appends_post_tool_hook_feedback_to_tool_result() {
+        struct TwoCallApiClient {
+            calls: usize,
+        }
+
+        impl ApiClient for TwoCallApiClient {
+            fn stream(&mut self, request: ApiRequest) -> Result<Vec<AssistantEvent>, RuntimeError> {
+                self.calls += 1;
+                match self.calls {
+                    1 => Ok(vec![
+                        AssistantEvent::ToolUse {
+                            id: "tool-1".to_string(),
+                            name: "add".to_string(),
+                            input: r#"{"lhs":2,"rhs":2}"#.to_string(),
+                        },
+                        AssistantEvent::MessageStop,
+                    ]),
+                    2 => {
+                        assert!(request
+                            .messages
+                            .iter()
+                            .any(|message| message.role == MessageRole::Tool));
+                        Ok(vec![
+                            AssistantEvent::TextDelta("done".to_string()),
+                            AssistantEvent::MessageStop,
+                        ])
+                    }
+                    _ => Err(RuntimeError::new("unexpected extra API call")),
+                }
+            }
+        }
+
+        let mut runtime = ConversationRuntime::new_with_features(
+            Session::new(),
+            TwoCallApiClient { calls: 0 },
+            StaticToolExecutor::new().register("add", |_input| Ok("4".to_string())),
+            PermissionPolicy::new(PermissionMode::DangerFullAccess),
+            vec!["system".to_string()],
+            &RuntimeFeatureConfig::default().with_hooks(RuntimeHookConfig::new(
+                vec![shell_snippet("printf 'pre hook ran'")],
+                vec![shell_snippet("printf 'post hook ran'")],
+            )),
+        );
+
+        let summary = runtime
+            .run_turn("use add", None)
+            .expect("tool loop succeeds");
+
+        assert_eq!(summary.tool_results.len(), 1);
+        let ContentBlock::ToolResult {
+            is_error, output, ..
+        } = &summary.tool_results[0].blocks[0]
+        else {
+            panic!("expected tool result block");
+        };
+        assert!(
+            !*is_error,
+            "post hook should preserve non-error result: {output:?}"
+        );
+        assert!(
+            output.contains('4'),
+            "tool output missing value: {output:?}"
+        );
+        assert!(
+            output.contains("pre hook ran"),
+            "tool output missing pre hook feedback: {output:?}"
+        );
+        assert!(
+            output.contains("post hook ran"),
+            "tool output missing post hook feedback: {output:?}"
+        );
+    }
+
     #[test]
     fn reconstructs_usage_tracker_from_restored_session() {
         struct SimpleApi;
@@ -581,4 +788,14 @@ mod tests {
             MessageRole::System
         );
     }
+
+    #[cfg(windows)]
+    fn shell_snippet(script: &str) -> String {
+        script.replace('\'', "\"")
+    }
+
+    #[cfg(not(windows))]
+    fn shell_snippet(script: &str) -> String {
+        script.to_string()
+    }
 }

rust/crates/runtime/src/hooks.rs

@@ -0,0 +1,357 @@
+use std::ffi::OsStr;
+use std::process::Command;
+
+use serde_json::json;
+
+use crate::config::{RuntimeFeatureConfig, RuntimeHookConfig};
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum HookEvent {
+    PreToolUse,
+    PostToolUse,
+}
+
+impl HookEvent {
+    fn as_str(self) -> &'static str {
+        match self {
+            Self::PreToolUse => "PreToolUse",
+            Self::PostToolUse => "PostToolUse",
+        }
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct HookRunResult {
+    denied: bool,
+    messages: Vec<String>,
+}
+
+impl HookRunResult {
+    #[must_use]
+    pub fn allow(messages: Vec<String>) -> Self {
+        Self {
+            denied: false,
+            messages,
+        }
+    }
+
+    #[must_use]
+    pub fn is_denied(&self) -> bool {
+        self.denied
+    }
+
+    #[must_use]
+    pub fn messages(&self) -> &[String] {
+        &self.messages
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq, Default)]
+pub struct HookRunner {
+    config: RuntimeHookConfig,
+}
+
+#[derive(Debug, Clone, Copy)]
+struct HookCommandRequest<'a> {
+    event: HookEvent,
+    tool_name: &'a str,
+    tool_input: &'a str,
+    tool_output: Option<&'a str>,
+    is_error: bool,
+    payload: &'a str,
+}
+
+impl HookRunner {
+    #[must_use]
+    pub fn new(config: RuntimeHookConfig) -> Self {
+        Self { config }
+    }
+
+    #[must_use]
+    pub fn from_feature_config(feature_config: &RuntimeFeatureConfig) -> Self {
+        Self::new(feature_config.hooks().clone())
+    }
+
+    #[must_use]
+    pub fn run_pre_tool_use(&self, tool_name: &str, tool_input: &str) -> HookRunResult {
+        self.run_commands(
+            HookEvent::PreToolUse,
+            self.config.pre_tool_use(),
+            tool_name,
+            tool_input,
+            None,
+            false,
+        )
+    }
+
+    #[must_use]
+    pub fn run_post_tool_use(
+        &self,
+        tool_name: &str,
+        tool_input: &str,
+        tool_output: &str,
+        is_error: bool,
+    ) -> HookRunResult {
+        self.run_commands(
+            HookEvent::PostToolUse,
+            self.config.post_tool_use(),
+            tool_name,
+            tool_input,
+            Some(tool_output),
+            is_error,
+        )
+    }
+
+    fn run_commands(
+        &self,
+        event: HookEvent,
+        commands: &[String],
+        tool_name: &str,
+        tool_input: &str,
+        tool_output: Option<&str>,
+        is_error: bool,
+    ) -> HookRunResult {
+        if commands.is_empty() {
+            return HookRunResult::allow(Vec::new());
+        }
+
+        let payload = json!({
+            "hook_event_name": event.as_str(),
+            "tool_name": tool_name,
+            "tool_input": parse_tool_input(tool_input),
+            "tool_input_json": tool_input,
+            "tool_output": tool_output,
+            "tool_result_is_error": is_error,
+        })
+        .to_string();
+
+        let mut messages = Vec::new();
+
+        for command in commands {
+            match Self::run_command(
+                command,
+                HookCommandRequest {
+                    event,
+                    tool_name,
+                    tool_input,
+                    tool_output,
+                    is_error,
+                    payload: &payload,
+                },
+            ) {
+                HookCommandOutcome::Allow { message } => {
+                    if let Some(message) = message {
+                        messages.push(message);
+                    }
+                }
+                HookCommandOutcome::Deny { message } => {
+                    let message = message.unwrap_or_else(|| {
+                        format!("{} hook denied tool `{tool_name}`", event.as_str())
+                    });
+                    messages.push(message);
+                    return HookRunResult {
+                        denied: true,
+                        messages,
+                    };
+                }
+                HookCommandOutcome::Warn { message } => messages.push(message),
+            }
+        }
+
+        HookRunResult::allow(messages)
+    }
+
+    fn run_command(command: &str, request: HookCommandRequest<'_>) -> HookCommandOutcome {
+        let mut child = shell_command(command);
+        child.stdin(std::process::Stdio::piped());
+        child.stdout(std::process::Stdio::piped());
+        child.stderr(std::process::Stdio::piped());
+        child.env("HOOK_EVENT", request.event.as_str());
+        child.env("HOOK_TOOL_NAME", request.tool_name);
+        child.env("HOOK_TOOL_INPUT", request.tool_input);
+        child.env(
+            "HOOK_TOOL_IS_ERROR",
+            if request.is_error { "1" } else { "0" },
+        );
+        if let Some(tool_output) = request.tool_output {
+            child.env("HOOK_TOOL_OUTPUT", tool_output);
+        }
+
+        match child.output_with_stdin(request.payload.as_bytes()) {
+            Ok(output) => {
+                let stdout = String::from_utf8_lossy(&output.stdout).trim().to_string();
+                let stderr = String::from_utf8_lossy(&output.stderr).trim().to_string();
+                let message = (!stdout.is_empty()).then_some(stdout);
+                match output.status.code() {
+                    Some(0) => HookCommandOutcome::Allow { message },
+                    Some(2) => HookCommandOutcome::Deny { message },
+                    Some(code) => HookCommandOutcome::Warn {
+                        message: format_hook_warning(
+                            command,
+                            code,
+                            message.as_deref(),
+                            stderr.as_str(),
+                        ),
+                    },
+                    None => HookCommandOutcome::Warn {
+                        message: format!(
+                            "{} hook `{command}` terminated by signal while handling `{}`",
+                            request.event.as_str(),
+                            request.tool_name
+                        ),
+                    },
+                }
+            }
+            Err(error) => HookCommandOutcome::Warn {
+                message: format!(
+                    "{} hook `{command}` failed to start for `{}`: {error}",
+                    request.event.as_str(),
+                    request.tool_name
+                ),
+            },
+        }
+    }
+}
+
+enum HookCommandOutcome {
+    Allow { message: Option<String> },
+    Deny { message: Option<String> },
+    Warn { message: String },
+}
+
+fn parse_tool_input(tool_input: &str) -> serde_json::Value {
+    serde_json::from_str(tool_input).unwrap_or_else(|_| json!({ "raw": tool_input }))
+}
+
+fn format_hook_warning(command: &str, code: i32, stdout: Option<&str>, stderr: &str) -> String {
+    let mut message =
+        format!("Hook `{command}` exited with status {code}; allowing tool execution to continue");
+    if let Some(stdout) = stdout.filter(|stdout| !stdout.is_empty()) {
+        message.push_str(": ");
+        message.push_str(stdout);
+    } else if !stderr.is_empty() {
+        message.push_str(": ");
+        message.push_str(stderr);
+    }
+    message
+}
+
+fn shell_command(command: &str) -> CommandWithStdin {
+    #[cfg(windows)]
+    let mut command_builder = {
+        let mut command_builder = Command::new("cmd");
+        command_builder.arg("/C").arg(command);
+        CommandWithStdin::new(command_builder)
+    };
+
+    #[cfg(not(windows))]
+    let command_builder = {
+        let mut command_builder = Command::new("sh");
+        command_builder.arg("-lc").arg(command);
+        CommandWithStdin::new(command_builder)
+    };
+
+    command_builder
+}
+
+struct CommandWithStdin {
+    command: Command,
+}
+
+impl CommandWithStdin {
+    fn new(command: Command) -> Self {
+        Self { command }
+    }
+
+    fn stdin(&mut self, cfg: std::process::Stdio) -> &mut Self {
+        self.command.stdin(cfg);
+        self
+    }
+
+    fn stdout(&mut self, cfg: std::process::Stdio) -> &mut Self {
+        self.command.stdout(cfg);
+        self
+    }
+
+    fn stderr(&mut self, cfg: std::process::Stdio) -> &mut Self {
+        self.command.stderr(cfg);
+        self
+    }
+
+    fn env<K, V>(&mut self, key: K, value: V) -> &mut Self
+    where
+        K: AsRef<OsStr>,
+        V: AsRef<OsStr>,
+    {
+        self.command.env(key, value);
+        self
+    }
+
+    fn output_with_stdin(&mut self, stdin: &[u8]) -> std::io::Result<std::process::Output> {
+        let mut child = self.command.spawn()?;
+        if let Some(mut child_stdin) = child.stdin.take() {
+            use std::io::Write;
+            child_stdin.write_all(stdin)?;
+        }
+        child.wait_with_output()
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{HookRunResult, HookRunner};
+    use crate::config::{RuntimeFeatureConfig, RuntimeHookConfig};
+
+    #[test]
+    fn allows_exit_code_zero_and_captures_stdout() {
+        let runner = HookRunner::new(RuntimeHookConfig::new(
+            vec![shell_snippet("printf 'pre ok'")],
+            Vec::new(),
+        ));
+
+        let result = runner.run_pre_tool_use("Read", r#"{"path":"README.md"}"#);
+
+        assert_eq!(result, HookRunResult::allow(vec!["pre ok".to_string()]));
+    }
+
+    #[test]
+    fn denies_exit_code_two() {
+        let runner = HookRunner::new(RuntimeHookConfig::new(
+            vec![shell_snippet("printf 'blocked by hook'; exit 2")],
+            Vec::new(),
+        ));
+
+        let result = runner.run_pre_tool_use("Bash", r#"{"command":"pwd"}"#);
+
+        assert!(result.is_denied());
+        assert_eq!(result.messages(), &["blocked by hook".to_string()]);
+    }
+
+    #[test]
+    fn warns_for_other_non_zero_statuses() {
+        let runner = HookRunner::from_feature_config(&RuntimeFeatureConfig::default().with_hooks(
+            RuntimeHookConfig::new(
+                vec![shell_snippet("printf 'warning hook'; exit 1")],
+                Vec::new(),
+            ),
+        ));
+
+        let result = runner.run_pre_tool_use("Edit", r#"{"file":"src/lib.rs"}"#);
+
+        assert!(!result.is_denied());
+        assert!(result
+            .messages()
+            .iter()
+            .any(|message| message.contains("allowing tool execution to continue")));
+    }
+
+    #[cfg(windows)]
+    fn shell_snippet(script: &str) -> String {
+        script.replace('\'', "\"")
+    }
+
+    #[cfg(not(windows))]
+    fn shell_snippet(script: &str) -> String {
+        script.to_string()
+    }
+}

rust/crates/runtime/src/lib.rs

@@ -4,6 +4,7 @@ mod compact;
 mod config;
 mod conversation;
 mod file_ops;
+mod hooks;
 mod json;
 mod mcp;
 mod mcp_client;
@@ -26,8 +27,8 @@ pub use config::{
     ConfigEntry, ConfigError, ConfigLoader, ConfigSource, McpClaudeAiProxyServerConfig,
     McpConfigCollection, McpOAuthConfig, McpRemoteServerConfig, McpSdkServerConfig,
     McpServerConfig, McpStdioServerConfig, McpTransport, McpWebSocketServerConfig, OAuthConfig,
-    ResolvedPermissionMode, RuntimeConfig, RuntimeFeatureConfig, ScopedMcpServerConfig,
+    ResolvedPermissionMode, RuntimeConfig, RuntimeFeatureConfig, RuntimeHookConfig,
-    CLAUDE_CODE_SETTINGS_SCHEMA_NAME,
+    ScopedMcpServerConfig, CLAUDE_CODE_SETTINGS_SCHEMA_NAME,
 };
 pub use conversation::{
     ApiClient, ApiRequest, AssistantEvent, ConversationRuntime, RuntimeError, StaticToolExecutor,
@@ -38,6 +39,7 @@ pub use file_ops::{
     GrepSearchInput, GrepSearchOutput, ReadFileOutput, StructuredPatchHunk, TextFilePayload,
     WriteFileOutput,
 };
+pub use hooks::{HookEvent, HookRunResult, HookRunner};
 pub use mcp::{
     mcp_server_signature, mcp_tool_name, mcp_tool_prefix, normalize_name_for_mcp,
     scoped_mcp_config_hash, unwrap_ccr_proxy_url,

rust/crates/rusty-claude-cli/src/main.rs

@@ -12,8 +12,9 @@ use std::process::Command;
 use std::time::{SystemTime, UNIX_EPOCH};
 
 use api::{
-    resolve_startup_auth_source, AnthropicClient, AuthSource, ContentBlockDelta, InputContentBlock,
+    detect_provider_kind, max_tokens_for_model, resolve_model_alias, resolve_startup_auth_source,
-    InputMessage, MessageRequest, MessageResponse, OutputContentBlock,
+    AnthropicClient, AuthSource, ContentBlockDelta, InputContentBlock, InputMessage,
+    MessageRequest, MessageResponse, OutputContentBlock, ProviderClient, ProviderKind,
     StreamEvent as ApiStreamEvent, ToolChoice, ToolDefinition, ToolResultContentBlock,
 };
 
@@ -27,7 +28,7 @@ use runtime::{
     clear_oauth_credentials, generate_pkce_pair, generate_state, load_system_prompt,
     parse_oauth_callback_request_target, save_oauth_credentials, ApiClient, ApiRequest,
     AssistantEvent, CompactionConfig, ConfigLoader, ConfigSource, ContentBlock,
-    ConversationMessage, ConversationRuntime, MessageRole, OAuthAuthorizationRequest,
+    ConversationMessage, ConversationRuntime, MessageRole, OAuthAuthorizationRequest, OAuthConfig,
     OAuthTokenExchangeRequest, PermissionMode, PermissionPolicy, ProjectContext, RuntimeError,
     Session, TokenUsage, ToolError, ToolExecutor, UsageTracker,
 };
@@ -35,13 +36,6 @@ use serde_json::json;
 use tools::{execute_tool, mvp_tool_specs, ToolSpec};
 
 const DEFAULT_MODEL: &str = "claude-opus-4-6";
-fn max_tokens_for_model(model: &str) -> u32 {
-    if model.contains("opus") {
-        32_000
-    } else {
-        64_000
-    }
-}
 const DEFAULT_DATE: &str = "2026-03-31";
 const DEFAULT_OAUTH_CALLBACK_PORT: u16 = 4545;
 const VERSION: &str = env!("CARGO_PKG_VERSION");
@@ -196,6 +190,25 @@ fn parse_args(args: &[String]) -> Result<CliAction, String> {
                 permission_mode = PermissionMode::DangerFullAccess;
                 index += 1;
             }
+            "-p" => {
+                // Claude Code compat: -p "prompt" = one-shot prompt
+                let prompt = args[index + 1..].join(" ");
+                if prompt.trim().is_empty() {
+                    return Err("-p requires a prompt string".to_string());
+                }
+                return Ok(CliAction::Prompt {
+                    prompt,
+                    model: resolve_model_alias(&model).to_string(),
+                    output_format,
+                    allowed_tools: normalize_allowed_tools(&allowed_tool_values)?,
+                    permission_mode,
+                });
+            }
+            "--print" => {
+                // Claude Code compat: --print makes output non-interactive
+                output_format = CliOutputFormat::Text;
+                index += 1;
+            }
             "--allowedTools" | "--allowed-tools" => {
                 let value = args
                     .get(index + 1)
@@ -269,15 +282,6 @@ fn parse_args(args: &[String]) -> Result<CliAction, String> {
     }
 }
 
-fn resolve_model_alias(model: &str) -> &str {
-    match model {
-        "opus" => "claude-opus-4-6",
-        "sonnet" => "claude-sonnet-4-6",
-        "haiku" => "claude-haiku-4-5-20251213",
-        _ => model,
-    }
-}
-
 fn normalize_allowed_tools(values: &[String]) -> Result<Option<AllowedToolSet>, String> {
     if values.is_empty() {
         return Ok(None);
@@ -428,15 +432,26 @@ fn print_bootstrap_plan() {
     }
 }
 
+fn default_oauth_config() -> OAuthConfig {
+    OAuthConfig {
+        client_id: String::from("9d1c250a-e61b-44d9-88ed-5944d1962f5e"),
+        authorize_url: String::from("https://platform.claude.com/oauth/authorize"),
+        token_url: String::from("https://platform.claude.com/v1/oauth/token"),
+        callback_port: None,
+        manual_redirect_url: None,
+        scopes: vec![
+            String::from("user:profile"),
+            String::from("user:inference"),
+            String::from("user:sessions:claude_code"),
+        ],
+    }
+}
+
 fn run_login() -> Result<(), Box<dyn std::error::Error>> {
     let cwd = env::current_dir()?;
     let config = ConfigLoader::default_for(&cwd).load()?;
-    let oauth = config.oauth().ok_or_else(|| {
+    let default_oauth = default_oauth_config();
-        io::Error::new(
+    let oauth = config.oauth().unwrap_or(&default_oauth);
-            io::ErrorKind::NotFound,
-            "OAuth config is missing. Add settings.oauth.clientId/authorizeUrl/tokenUrl first.",
-        )
-    })?;
     let callback_port = oauth.callback_port.unwrap_or(DEFAULT_OAUTH_CALLBACK_PORT);
     let redirect_uri = runtime::loopback_redirect_uri(callback_port);
     let pkce = generate_pkce_pair()?;
@@ -950,7 +965,7 @@ struct LiveCli {
     allowed_tools: Option<AllowedToolSet>,
     permission_mode: PermissionMode,
     system_prompt: Vec<String>,
-    runtime: ConversationRuntime<AnthropicRuntimeClient, CliToolExecutor>,
+    runtime: ConversationRuntime<ProviderRuntimeClient, CliToolExecutor>,
     session: SessionHandle,
 }
 
@@ -1873,6 +1888,15 @@ fn build_system_prompt() -> Result<Vec<String>, Box<dyn std::error::Error>> {
     )?)
 }
 
+fn build_runtime_feature_config(
+) -> Result<runtime::RuntimeFeatureConfig, Box<dyn std::error::Error>> {
+    let cwd = env::current_dir()?;
+    Ok(ConfigLoader::default_for(cwd)
+        .load()?
+        .feature_config()
+        .clone())
+}
+
 fn build_runtime(
     session: Session,
     model: String,
@@ -1881,14 +1905,16 @@ fn build_runtime(
     emit_output: bool,
     allowed_tools: Option<AllowedToolSet>,
     permission_mode: PermissionMode,
-) -> Result<ConversationRuntime<AnthropicRuntimeClient, CliToolExecutor>, Box<dyn std::error::Error>>
+) -> Result<ConversationRuntime<ProviderRuntimeClient, CliToolExecutor>, Box<dyn std::error::Error>>
 {
-    Ok(ConversationRuntime::new(
+    let feature_config = build_runtime_feature_config()?;
+    Ok(ConversationRuntime::new_with_features(
         session,
-        AnthropicRuntimeClient::new(model, enable_tools, emit_output, allowed_tools.clone())?,
+        ProviderRuntimeClient::new(model, enable_tools, emit_output, allowed_tools.clone())?,
         CliToolExecutor::new(allowed_tools, emit_output),
         permission_policy(permission_mode),
         system_prompt,
+        &feature_config,
     ))
 }
 
@@ -1938,26 +1964,33 @@ impl runtime::PermissionPrompter for CliPermissionPrompter {
     }
 }
 
-struct AnthropicRuntimeClient {
+struct ProviderRuntimeClient {
     runtime: tokio::runtime::Runtime,
-    client: AnthropicClient,
+    client: ProviderClient,
     model: String,
     enable_tools: bool,
     emit_output: bool,
     allowed_tools: Option<AllowedToolSet>,
 }
 
-impl AnthropicRuntimeClient {
+impl ProviderRuntimeClient {
     fn new(
         model: String,
         enable_tools: bool,
         emit_output: bool,
         allowed_tools: Option<AllowedToolSet>,
     ) -> Result<Self, Box<dyn std::error::Error>> {
+        let model = resolve_model_alias(&model).to_string();
+        let client = match detect_provider_kind(&model) {
+            ProviderKind::Anthropic => ProviderClient::from_model_with_anthropic_auth(
+                &model,
+                Some(resolve_cli_auth_source()?),
+            )?,
+            ProviderKind::Xai | ProviderKind::OpenAi => ProviderClient::from_model(&model)?,
+        };
         Ok(Self {
             runtime: tokio::runtime::Runtime::new()?,
-            client: AnthropicClient::from_auth(resolve_cli_auth_source()?)
+            client,
-                .with_base_url(api::read_base_url()),
             model,
             enable_tools,
             emit_output,
@@ -1976,7 +2009,7 @@ fn resolve_cli_auth_source() -> Result<AuthSource, Box<dyn std::error::Error>> {
     })?)
 }
 
-impl ApiClient for AnthropicRuntimeClient {
+impl ApiClient for ProviderRuntimeClient {
     #[allow(clippy::too_many_lines)]
     fn stream(&mut self, request: ApiRequest) -> Result<Vec<AssistantEvent>, RuntimeError> {
         let message_request = MessageRequest {
@@ -2014,7 +2047,7 @@ impl ApiClient for AnthropicRuntimeClient {
             let renderer = TerminalRenderer::new();
             let mut markdown_stream = MarkdownStreamState::default();
             let mut events = Vec::new();
-            let mut pending_tool: Option<(String, String, String)> = None;
+            let mut pending_tools: BTreeMap<u32, (String, String, String)> = BTreeMap::new();
             let mut saw_stop = false;
 
             while let Some(event) = stream
@@ -2025,15 +2058,23 @@ impl ApiClient for AnthropicRuntimeClient {
                 match event {
                     ApiStreamEvent::MessageStart(start) => {
                         for block in start.message.content {
-                            push_output_block(block, out, &mut events, &mut pending_tool, true)?;
+                            push_output_block(
+                                block,
+                                0,
+                                out,
+                                &mut events,
+                                &mut pending_tools,
+                                true,
+                            )?;
                         }
                     }
                     ApiStreamEvent::ContentBlockStart(start) => {
                         push_output_block(
                             start.content_block,
+                            start.index,
                             out,
                             &mut events,
-                            &mut pending_tool,
+                            &mut pending_tools,
                             true,
                         )?;
                     }
@@ -2049,18 +2090,18 @@ impl ApiClient for AnthropicRuntimeClient {
                             }
                         }
                         ContentBlockDelta::InputJsonDelta { partial_json } => {
-                            if let Some((_, _, input)) = &mut pending_tool {
+                            if let Some((_, _, input)) = pending_tools.get_mut(&delta.index) {
                                 input.push_str(&partial_json);
                             }
                         }
                     },
-                    ApiStreamEvent::ContentBlockStop(_) => {
+                    ApiStreamEvent::ContentBlockStop(stop) => {
                         if let Some(rendered) = markdown_stream.flush(&renderer) {
                             write!(out, "{rendered}")
                                 .and_then(|()| out.flush())
                                 .map_err(|error| RuntimeError::new(error.to_string()))?;
                         }
-                        if let Some((id, name, input)) = pending_tool.take() {
+                        if let Some((id, name, input)) = pending_tools.remove(&stop.index) {
                             // Display tool call now that input is fully accumulated
                             writeln!(out, "\n{}", format_tool_call_start(&name, &input))
                                 .and_then(|()| out.flush())
@@ -2524,9 +2565,10 @@ fn truncate_for_summary(value: &str, limit: usize) -> String {
 
 fn push_output_block(
     block: OutputContentBlock,
+    block_index: u32,
     out: &mut (impl Write + ?Sized),
     events: &mut Vec<AssistantEvent>,
-    pending_tool: &mut Option<(String, String, String)>,
+    pending_tools: &mut BTreeMap<u32, (String, String, String)>,
     streaming_tool_input: bool,
 ) -> Result<(), RuntimeError> {
     match block {
@@ -2551,7 +2593,7 @@ fn push_output_block(
             } else {
                 input.to_string()
             };
-            *pending_tool = Some((id, name, initial_input));
+            pending_tools.insert(block_index, (id, name, initial_input));
         }
     }
     Ok(())
@@ -2562,11 +2604,13 @@ fn response_to_events(
     out: &mut (impl Write + ?Sized),
 ) -> Result<Vec<AssistantEvent>, RuntimeError> {
     let mut events = Vec::new();
-    let mut pending_tool = None;
+    let mut pending_tools = BTreeMap::new();
 
-    for block in response.content {
+    for (index, block) in response.content.into_iter().enumerate() {
-        push_output_block(block, out, &mut events, &mut pending_tool, false)?;
+        let index =
-        if let Some((id, name, input)) = pending_tool.take() {
+            u32::try_from(index).map_err(|_| RuntimeError::new("response block index overflow"))?;
+        push_output_block(block, index, out, &mut events, &mut pending_tools, false)?;
+        if let Some((id, name, input)) = pending_tools.remove(&index) {
             events.push(AssistantEvent::ToolUse { id, name, input });
         }
     }
@@ -2792,6 +2836,7 @@ mod tests {
     use api::{MessageResponse, OutputContentBlock, Usage};
     use runtime::{AssistantEvent, ContentBlock, ConversationMessage, MessageRole, PermissionMode};
     use serde_json::json;
+    use std::collections::BTreeMap;
     use std::path::PathBuf;
 
     #[test]
@@ -2871,6 +2916,9 @@ mod tests {
         assert_eq!(resolve_model_alias("opus"), "claude-opus-4-6");
         assert_eq!(resolve_model_alias("sonnet"), "claude-sonnet-4-6");
         assert_eq!(resolve_model_alias("haiku"), "claude-haiku-4-5-20251213");
+        assert_eq!(resolve_model_alias("grok"), "grok-3");
+        assert_eq!(resolve_model_alias("grok-mini"), "grok-3-mini");
+        assert_eq!(resolve_model_alias("grok-2"), "grok-2");
         assert_eq!(resolve_model_alias("claude-opus"), "claude-opus");
     }
 
@@ -3338,15 +3386,16 @@ mod tests {
     fn push_output_block_renders_markdown_text() {
         let mut out = Vec::new();
         let mut events = Vec::new();
-        let mut pending_tool = None;
+        let mut pending_tools = BTreeMap::new();
 
         push_output_block(
             OutputContentBlock::Text {
                 text: "# Heading".to_string(),
             },
+            0,
             &mut out,
             &mut events,
-            &mut pending_tool,
+            &mut pending_tools,
             false,
         )
         .expect("text block should render");
@@ -3360,7 +3409,7 @@ mod tests {
     fn push_output_block_skips_empty_object_prefix_for_tool_streams() {
         let mut out = Vec::new();
         let mut events = Vec::new();
-        let mut pending_tool = None;
+        let mut pending_tools = BTreeMap::new();
 
         push_output_block(
             OutputContentBlock::ToolUse {
@@ -3368,20 +3417,83 @@ mod tests {
                 name: "read_file".to_string(),
                 input: json!({}),
             },
+            1,
             &mut out,
             &mut events,
-            &mut pending_tool,
+            &mut pending_tools,
             true,
         )
         .expect("tool block should accumulate");
 
         assert!(events.is_empty());
         assert_eq!(
-            pending_tool,
+            pending_tools.remove(&1),
             Some(("tool-1".to_string(), "read_file".to_string(), String::new(),))
         );
     }
 
+    #[test]
+    fn pending_tools_preserve_multiple_streaming_tool_calls_by_index() {
+        let mut out = Vec::new();
+        let mut events = Vec::new();
+        let mut pending_tools = BTreeMap::new();
+
+        push_output_block(
+            OutputContentBlock::ToolUse {
+                id: "tool-1".to_string(),
+                name: "read_file".to_string(),
+                input: json!({}),
+            },
+            1,
+            &mut out,
+            &mut events,
+            &mut pending_tools,
+            true,
+        )
+        .expect("first tool should accumulate");
+        push_output_block(
+            OutputContentBlock::ToolUse {
+                id: "tool-2".to_string(),
+                name: "grep_search".to_string(),
+                input: json!({}),
+            },
+            2,
+            &mut out,
+            &mut events,
+            &mut pending_tools,
+            true,
+        )
+        .expect("second tool should accumulate");
+
+        pending_tools
+            .get_mut(&1)
+            .expect("first tool pending")
+            .2
+            .push_str("{\"path\":\"src/main.rs\"}");
+        pending_tools
+            .get_mut(&2)
+            .expect("second tool pending")
+            .2
+            .push_str("{\"pattern\":\"TODO\"}");
+
+        assert_eq!(
+            pending_tools.remove(&1),
+            Some((
+                "tool-1".to_string(),
+                "read_file".to_string(),
+                "{\"path\":\"src/main.rs\"}".to_string(),
+            ))
+        );
+        assert_eq!(
+            pending_tools.remove(&2),
+            Some((
+                "tool-2".to_string(),
+                "grep_search".to_string(),
+                "{\"pattern\":\"TODO\"}".to_string(),
+            ))
+        );
+    }
+
     #[test]
     fn response_to_events_preserves_empty_object_json_input_outside_streaming() {
         let mut out = Vec::new();

rust/crates/tools/Cargo.toml

@@ -6,10 +6,12 @@ license.workspace = true
 publish.workspace = true
 
 [dependencies]
+api = { path = "../api" }
 runtime = { path = "../runtime" }
 reqwest = { version = "0.12", default-features = false, features = ["blocking", "rustls-tls"] }
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
+tokio = { version = "1", features = ["rt-multi-thread"] }
 
 [lints]
 workspace = true

rust/crates/tools/src/lib.rs

@@ -3,10 +3,17 @@ use std::path::{Path, PathBuf};
 use std::process::Command;
 use std::time::{Duration, Instant};
 
+use api::{
+    max_tokens_for_model, resolve_model_alias, ContentBlockDelta, InputContentBlock, InputMessage,
+    MessageRequest, MessageResponse, OutputContentBlock, ProviderClient,
+    StreamEvent as ApiStreamEvent, ToolChoice, ToolDefinition, ToolResultContentBlock,
+};
 use reqwest::blocking::Client;
 use runtime::{
-    edit_file, execute_bash, glob_search, grep_search, read_file, write_file, BashCommandInput,
+    edit_file, execute_bash, glob_search, grep_search, load_system_prompt, read_file, write_file,
-    GrepSearchInput, PermissionMode,
+    ApiClient, ApiRequest, AssistantEvent, BashCommandInput, ContentBlock, ConversationMessage,
+    ConversationRuntime, GrepSearchInput, MessageRole, PermissionMode, PermissionPolicy,
+    RuntimeError, Session, TokenUsage, ToolError, ToolExecutor,
 };
 use serde::{Deserialize, Serialize};
 use serde_json::{json, Value};
@@ -702,7 +709,7 @@ struct SkillOutput {
     prompt: String,
 }
 
-#[derive(Debug, Serialize, Deserialize)]
+#[derive(Debug, Clone, Serialize, Deserialize)]
 struct AgentOutput {
     #[serde(rename = "agentId")]
     agent_id: String,
@@ -718,6 +725,20 @@ struct AgentOutput {
     manifest_file: String,
     #[serde(rename = "createdAt")]
     created_at: String,
+    #[serde(rename = "startedAt", skip_serializing_if = "Option::is_none")]
+    started_at: Option<String>,
+    #[serde(rename = "completedAt", skip_serializing_if = "Option::is_none")]
+    completed_at: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    error: Option<String>,
+}
+
+#[derive(Debug, Clone)]
+struct AgentJob {
+    manifest: AgentOutput,
+    prompt: String,
+    system_prompt: Vec<String>,
+    allowed_tools: BTreeSet<String>,
 }
 
 #[derive(Debug, Serialize)]
@@ -1315,7 +1336,18 @@ fn resolve_skill_path(skill: &str) -> Result<std::path::PathBuf, String> {
     Err(format!("unknown skill: {requested}"))
 }
 
+const DEFAULT_AGENT_MODEL: &str = "claude-opus-4-6";
+const DEFAULT_AGENT_SYSTEM_DATE: &str = "2026-03-31";
+const DEFAULT_AGENT_MAX_ITERATIONS: usize = 32;
+
 fn execute_agent(input: AgentInput) -> Result<AgentOutput, String> {
+    execute_agent_with_spawn(input, spawn_agent_job)
+}
+
+fn execute_agent_with_spawn<F>(input: AgentInput, spawn_fn: F) -> Result<AgentOutput, String>
+where
+    F: FnOnce(AgentJob) -> Result<(), String>,
+{
     if input.description.trim().is_empty() {
         return Err(String::from("description must not be empty"));
     }
@@ -1329,6 +1361,7 @@ fn execute_agent(input: AgentInput) -> Result<AgentOutput, String> {
     let output_file = output_dir.join(format!("{agent_id}.md"));
     let manifest_file = output_dir.join(format!("{agent_id}.json"));
     let normalized_subagent_type = normalize_subagent_type(input.subagent_type.as_deref());
+    let model = resolve_agent_model(input.model.as_deref());
     let agent_name = input
         .name
         .as_deref()
@@ -1336,6 +1369,8 @@ fn execute_agent(input: AgentInput) -> Result<AgentOutput, String> {
         .filter(|name| !name.is_empty())
         .unwrap_or_else(|| slugify_agent_name(&input.description));
     let created_at = iso8601_now();
+    let system_prompt = build_agent_system_prompt(&normalized_subagent_type)?;
+    let allowed_tools = allowed_tools_for_subagent(&normalized_subagent_type);
 
     let output_contents = format!(
         "# Agent Task
@@ -1359,21 +1394,516 @@ fn execute_agent(input: AgentInput) -> Result<AgentOutput, String> {
         name: agent_name,
         description: input.description,
         subagent_type: Some(normalized_subagent_type),
-        model: input.model,
+        model: Some(model),
-        status: String::from("queued"),
+        status: String::from("running"),
         output_file: output_file.display().to_string(),
         manifest_file: manifest_file.display().to_string(),
-        created_at,
+        created_at: created_at.clone(),
+        started_at: Some(created_at),
+        completed_at: None,
+        error: None,
     };
-    std::fs::write(
+    write_agent_manifest(&manifest)?;
-        &manifest_file,
+
-        serde_json::to_string_pretty(&manifest).map_err(|error| error.to_string())?,
+    let manifest_for_spawn = manifest.clone();
-    )
+    let job = AgentJob {
-    .map_err(|error| error.to_string())?;
+        manifest: manifest_for_spawn,
+        prompt: input.prompt,
+        system_prompt,
+        allowed_tools,
+    };
+    if let Err(error) = spawn_fn(job) {
+        let error = format!("failed to spawn sub-agent: {error}");
+        persist_agent_terminal_state(&manifest, "failed", None, Some(error.clone()))?;
+        return Err(error);
+    }
 
     Ok(manifest)
 }
 
+fn spawn_agent_job(job: AgentJob) -> Result<(), String> {
+    let thread_name = format!("clawd-agent-{}", job.manifest.agent_id);
+    std::thread::Builder::new()
+        .name(thread_name)
+        .spawn(move || {
+            let result =
+                std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| run_agent_job(&job)));
+            match result {
+                Ok(Ok(())) => {}
+                Ok(Err(error)) => {
+                    let _ =
+                        persist_agent_terminal_state(&job.manifest, "failed", None, Some(error));
+                }
+                Err(_) => {
+                    let _ = persist_agent_terminal_state(
+                        &job.manifest,
+                        "failed",
+                        None,
+                        Some(String::from("sub-agent thread panicked")),
+                    );
+                }
+            }
+        })
+        .map(|_| ())
+        .map_err(|error| error.to_string())
+}
+
+fn run_agent_job(job: &AgentJob) -> Result<(), String> {
+    let mut runtime = build_agent_runtime(job)?.with_max_iterations(DEFAULT_AGENT_MAX_ITERATIONS);
+    let summary = runtime
+        .run_turn(job.prompt.clone(), None)
+        .map_err(|error| error.to_string())?;
+    let final_text = final_assistant_text(&summary);
+    persist_agent_terminal_state(&job.manifest, "completed", Some(final_text.as_str()), None)
+}
+
+fn build_agent_runtime(
+    job: &AgentJob,
+) -> Result<ConversationRuntime<ProviderRuntimeClient, SubagentToolExecutor>, String> {
+    let model = job
+        .manifest
+        .model
+        .clone()
+        .unwrap_or_else(|| DEFAULT_AGENT_MODEL.to_string());
+    let allowed_tools = job.allowed_tools.clone();
+    let api_client = ProviderRuntimeClient::new(model, allowed_tools.clone())?;
+    let tool_executor = SubagentToolExecutor::new(allowed_tools);
+    Ok(ConversationRuntime::new(
+        Session::new(),
+        api_client,
+        tool_executor,
+        agent_permission_policy(),
+        job.system_prompt.clone(),
+    ))
+}
+
+fn build_agent_system_prompt(subagent_type: &str) -> Result<Vec<String>, String> {
+    let cwd = std::env::current_dir().map_err(|error| error.to_string())?;
+    let mut prompt = load_system_prompt(
+        cwd,
+        DEFAULT_AGENT_SYSTEM_DATE.to_string(),
+        std::env::consts::OS,
+        "unknown",
+    )
+    .map_err(|error| error.to_string())?;
+    prompt.push(format!(
+        "You are a background sub-agent of type `{subagent_type}`. Work only on the delegated task, use only the tools available to you, do not ask the user questions, and finish with a concise result."
+    ));
+    Ok(prompt)
+}
+
+fn resolve_agent_model(model: Option<&str>) -> String {
+    model
+        .map(str::trim)
+        .filter(|model| !model.is_empty())
+        .unwrap_or(DEFAULT_AGENT_MODEL)
+        .to_string()
+}
+
+fn allowed_tools_for_subagent(subagent_type: &str) -> BTreeSet<String> {
+    let tools = match subagent_type {
+        "Explore" => vec![
+            "read_file",
+            "glob_search",
+            "grep_search",
+            "WebFetch",
+            "WebSearch",
+            "ToolSearch",
+            "Skill",
+            "StructuredOutput",
+        ],
+        "Plan" => vec![
+            "read_file",
+            "glob_search",
+            "grep_search",
+            "WebFetch",
+            "WebSearch",
+            "ToolSearch",
+            "Skill",
+            "TodoWrite",
+            "StructuredOutput",
+            "SendUserMessage",
+        ],
+        "Verification" => vec![
+            "bash",
+            "read_file",
+            "glob_search",
+            "grep_search",
+            "WebFetch",
+            "WebSearch",
+            "ToolSearch",
+            "TodoWrite",
+            "StructuredOutput",
+            "SendUserMessage",
+            "PowerShell",
+        ],
+        "claude-code-guide" => vec![
+            "read_file",
+            "glob_search",
+            "grep_search",
+            "WebFetch",
+            "WebSearch",
+            "ToolSearch",
+            "Skill",
+            "StructuredOutput",
+            "SendUserMessage",
+        ],
+        "statusline-setup" => vec![
+            "bash",
+            "read_file",
+            "write_file",
+            "edit_file",
+            "glob_search",
+            "grep_search",
+            "ToolSearch",
+        ],
+        _ => vec![
+            "bash",
+            "read_file",
+            "write_file",
+            "edit_file",
+            "glob_search",
+            "grep_search",
+            "WebFetch",
+            "WebSearch",
+            "TodoWrite",
+            "Skill",
+            "ToolSearch",
+            "NotebookEdit",
+            "Sleep",
+            "SendUserMessage",
+            "Config",
+            "StructuredOutput",
+            "REPL",
+            "PowerShell",
+        ],
+    };
+    tools.into_iter().map(str::to_string).collect()
+}
+
+fn agent_permission_policy() -> PermissionPolicy {
+    mvp_tool_specs().into_iter().fold(
+        PermissionPolicy::new(PermissionMode::DangerFullAccess),
+        |policy, spec| policy.with_tool_requirement(spec.name, spec.required_permission),
+    )
+}
+
+fn write_agent_manifest(manifest: &AgentOutput) -> Result<(), String> {
+    std::fs::write(
+        &manifest.manifest_file,
+        serde_json::to_string_pretty(manifest).map_err(|error| error.to_string())?,
+    )
+    .map_err(|error| error.to_string())
+}
+
+fn persist_agent_terminal_state(
+    manifest: &AgentOutput,
+    status: &str,
+    result: Option<&str>,
+    error: Option<String>,
+) -> Result<(), String> {
+    append_agent_output(
+        &manifest.output_file,
+        &format_agent_terminal_output(status, result, error.as_deref()),
+    )?;
+    let mut next_manifest = manifest.clone();
+    next_manifest.status = status.to_string();
+    next_manifest.completed_at = Some(iso8601_now());
+    next_manifest.error = error;
+    write_agent_manifest(&next_manifest)
+}
+
+fn append_agent_output(path: &str, suffix: &str) -> Result<(), String> {
+    use std::io::Write as _;
+
+    let mut file = std::fs::OpenOptions::new()
+        .append(true)
+        .open(path)
+        .map_err(|error| error.to_string())?;
+    file.write_all(suffix.as_bytes())
+        .map_err(|error| error.to_string())
+}
+
+fn format_agent_terminal_output(status: &str, result: Option<&str>, error: Option<&str>) -> String {
+    let mut sections = vec![format!("\n## Result\n\n- status: {status}\n")];
+    if let Some(result) = result.filter(|value| !value.trim().is_empty()) {
+        sections.push(format!("\n### Final response\n\n{}\n", result.trim()));
+    }
+    if let Some(error) = error.filter(|value| !value.trim().is_empty()) {
+        sections.push(format!("\n### Error\n\n{}\n", error.trim()));
+    }
+    sections.join("")
+}
+
+struct ProviderRuntimeClient {
+    runtime: tokio::runtime::Runtime,
+    client: ProviderClient,
+    model: String,
+    allowed_tools: BTreeSet<String>,
+}
+
+impl ProviderRuntimeClient {
+    fn new(model: String, allowed_tools: BTreeSet<String>) -> Result<Self, String> {
+        let model = resolve_model_alias(&model).to_string();
+        let client = ProviderClient::from_model(&model).map_err(|error| error.to_string())?;
+        Ok(Self {
+            runtime: tokio::runtime::Runtime::new().map_err(|error| error.to_string())?,
+            client,
+            model,
+            allowed_tools,
+        })
+    }
+}
+
+impl ApiClient for ProviderRuntimeClient {
+    fn stream(&mut self, request: ApiRequest) -> Result<Vec<AssistantEvent>, RuntimeError> {
+        let tools = tool_specs_for_allowed_tools(Some(&self.allowed_tools))
+            .into_iter()
+            .map(|spec| ToolDefinition {
+                name: spec.name.to_string(),
+                description: Some(spec.description.to_string()),
+                input_schema: spec.input_schema,
+            })
+            .collect::<Vec<_>>();
+        let message_request = MessageRequest {
+            model: self.model.clone(),
+            max_tokens: max_tokens_for_model(&self.model),
+            messages: convert_messages(&request.messages),
+            system: (!request.system_prompt.is_empty()).then(|| request.system_prompt.join("\n\n")),
+            tools: (!tools.is_empty()).then_some(tools),
+            tool_choice: (!self.allowed_tools.is_empty()).then_some(ToolChoice::Auto),
+            stream: true,
+        };
+
+        self.runtime.block_on(async {
+            let mut stream = self
+                .client
+                .stream_message(&message_request)
+                .await
+                .map_err(|error| RuntimeError::new(error.to_string()))?;
+            let mut events = Vec::new();
+            let mut pending_tools: BTreeMap<u32, (String, String, String)> = BTreeMap::new();
+            let mut saw_stop = false;
+
+            while let Some(event) = stream
+                .next_event()
+                .await
+                .map_err(|error| RuntimeError::new(error.to_string()))?
+            {
+                match event {
+                    ApiStreamEvent::MessageStart(start) => {
+                        for block in start.message.content {
+                            push_output_block(block, 0, &mut events, &mut pending_tools, true);
+                        }
+                    }
+                    ApiStreamEvent::ContentBlockStart(start) => {
+                        push_output_block(
+                            start.content_block,
+                            start.index,
+                            &mut events,
+                            &mut pending_tools,
+                            true,
+                        );
+                    }
+                    ApiStreamEvent::ContentBlockDelta(delta) => match delta.delta {
+                        ContentBlockDelta::TextDelta { text } => {
+                            if !text.is_empty() {
+                                events.push(AssistantEvent::TextDelta(text));
+                            }
+                        }
+                        ContentBlockDelta::InputJsonDelta { partial_json } => {
+                            if let Some((_, _, input)) = pending_tools.get_mut(&delta.index) {
+                                input.push_str(&partial_json);
+                            }
+                        }
+                    },
+                    ApiStreamEvent::ContentBlockStop(stop) => {
+                        if let Some((id, name, input)) = pending_tools.remove(&stop.index) {
+                            events.push(AssistantEvent::ToolUse { id, name, input });
+                        }
+                    }
+                    ApiStreamEvent::MessageDelta(delta) => {
+                        events.push(AssistantEvent::Usage(TokenUsage {
+                            input_tokens: delta.usage.input_tokens,
+                            output_tokens: delta.usage.output_tokens,
+                            cache_creation_input_tokens: 0,
+                            cache_read_input_tokens: 0,
+                        }));
+                    }
+                    ApiStreamEvent::MessageStop(_) => {
+                        saw_stop = true;
+                        events.push(AssistantEvent::MessageStop);
+                    }
+                }
+            }
+
+            if !saw_stop
+                && events.iter().any(|event| {
+                    matches!(event, AssistantEvent::TextDelta(text) if !text.is_empty())
+                        || matches!(event, AssistantEvent::ToolUse { .. })
+                })
+            {
+                events.push(AssistantEvent::MessageStop);
+            }
+
+            if events
+                .iter()
+                .any(|event| matches!(event, AssistantEvent::MessageStop))
+            {
+                return Ok(events);
+            }
+
+            let response = self
+                .client
+                .send_message(&MessageRequest {
+                    stream: false,
+                    ..message_request.clone()
+                })
+                .await
+                .map_err(|error| RuntimeError::new(error.to_string()))?;
+            Ok(response_to_events(response))
+        })
+    }
+}
+
+struct SubagentToolExecutor {
+    allowed_tools: BTreeSet<String>,
+}
+
+impl SubagentToolExecutor {
+    fn new(allowed_tools: BTreeSet<String>) -> Self {
+        Self { allowed_tools }
+    }
+}
+
+impl ToolExecutor for SubagentToolExecutor {
+    fn execute(&mut self, tool_name: &str, input: &str) -> Result<String, ToolError> {
+        if !self.allowed_tools.contains(tool_name) {
+            return Err(ToolError::new(format!(
+                "tool `{tool_name}` is not enabled for this sub-agent"
+            )));
+        }
+        let value = serde_json::from_str(input)
+            .map_err(|error| ToolError::new(format!("invalid tool input JSON: {error}")))?;
+        execute_tool(tool_name, &value).map_err(ToolError::new)
+    }
+}
+
+fn tool_specs_for_allowed_tools(allowed_tools: Option<&BTreeSet<String>>) -> Vec<ToolSpec> {
+    mvp_tool_specs()
+        .into_iter()
+        .filter(|spec| allowed_tools.is_none_or(|allowed| allowed.contains(spec.name)))
+        .collect()
+}
+
+fn convert_messages(messages: &[ConversationMessage]) -> Vec<InputMessage> {
+    messages
+        .iter()
+        .filter_map(|message| {
+            let role = match message.role {
+                MessageRole::System | MessageRole::User | MessageRole::Tool => "user",
+                MessageRole::Assistant => "assistant",
+            };
+            let content = message
+                .blocks
+                .iter()
+                .map(|block| match block {
+                    ContentBlock::Text { text } => InputContentBlock::Text { text: text.clone() },
+                    ContentBlock::ToolUse { id, name, input } => InputContentBlock::ToolUse {
+                        id: id.clone(),
+                        name: name.clone(),
+                        input: serde_json::from_str(input)
+                            .unwrap_or_else(|_| serde_json::json!({ "raw": input })),
+                    },
+                    ContentBlock::ToolResult {
+                        tool_use_id,
+                        output,
+                        is_error,
+                        ..
+                    } => InputContentBlock::ToolResult {
+                        tool_use_id: tool_use_id.clone(),
+                        content: vec![ToolResultContentBlock::Text {
+                            text: output.clone(),
+                        }],
+                        is_error: *is_error,
+                    },
+                })
+                .collect::<Vec<_>>();
+            (!content.is_empty()).then(|| InputMessage {
+                role: role.to_string(),
+                content,
+            })
+        })
+        .collect()
+}
+
+fn push_output_block(
+    block: OutputContentBlock,
+    block_index: u32,
+    events: &mut Vec<AssistantEvent>,
+    pending_tools: &mut BTreeMap<u32, (String, String, String)>,
+    streaming_tool_input: bool,
+) {
+    match block {
+        OutputContentBlock::Text { text } => {
+            if !text.is_empty() {
+                events.push(AssistantEvent::TextDelta(text));
+            }
+        }
+        OutputContentBlock::ToolUse { id, name, input } => {
+            let initial_input = if streaming_tool_input
+                && input.is_object()
+                && input.as_object().is_some_and(serde_json::Map::is_empty)
+            {
+                String::new()
+            } else {
+                input.to_string()
+            };
+            pending_tools.insert(block_index, (id, name, initial_input));
+        }
+    }
+}
+
+fn response_to_events(response: MessageResponse) -> Vec<AssistantEvent> {
+    let mut events = Vec::new();
+    let mut pending_tools = BTreeMap::new();
+
+    for (index, block) in response.content.into_iter().enumerate() {
+        let index = u32::try_from(index).expect("response block index overflow");
+        push_output_block(block, index, &mut events, &mut pending_tools, false);
+        if let Some((id, name, input)) = pending_tools.remove(&index) {
+            events.push(AssistantEvent::ToolUse { id, name, input });
+        }
+    }
+
+    events.push(AssistantEvent::Usage(TokenUsage {
+        input_tokens: response.usage.input_tokens,
+        output_tokens: response.usage.output_tokens,
+        cache_creation_input_tokens: response.usage.cache_creation_input_tokens,
+        cache_read_input_tokens: response.usage.cache_read_input_tokens,
+    }));
+    events.push(AssistantEvent::MessageStop);
+    events
+}
+
+fn final_assistant_text(summary: &runtime::TurnSummary) -> String {
+    summary
+        .assistant_messages
+        .last()
+        .map(|message| {
+            message
+                .blocks
+                .iter()
+                .filter_map(|block| match block {
+                    ContentBlock::Text { text } => Some(text.as_str()),
+                    _ => None,
+                })
+                .collect::<Vec<_>>()
+                .join("")
+        })
+        .unwrap_or_default()
+}
+
 #[allow(clippy::needless_pass_by_value)]
 fn execute_tool_search(input: ToolSearchInput) -> ToolSearchOutput {
     let deferred = deferred_tool_specs();
@@ -2207,7 +2737,7 @@ fn execute_shell_command(
             persisted_output_path: None,
             persisted_output_size: None,
             sandbox_status: None,
-});
+        });
     }
 
     let mut process = std::process::Command::new(shell);
@@ -2276,7 +2806,7 @@ Command exceeded timeout of {timeout_ms} ms",
                     persisted_output_path: None,
                     persisted_output_size: None,
                     sandbox_status: None,
-});
+                });
             }
             std::thread::sleep(Duration::from_millis(10));
         }
@@ -2365,6 +2895,8 @@ fn parse_skill_description(contents: &str) -> Option<String> {
 
 #[cfg(test)]
 mod tests {
+    use std::collections::BTreeMap;
+    use std::collections::BTreeSet;
     use std::fs;
     use std::io::{Read, Write};
     use std::net::{SocketAddr, TcpListener};
@@ -2373,7 +2905,13 @@ mod tests {
     use std::thread;
     use std::time::Duration;
 
-    use super::{execute_tool, mvp_tool_specs};
+    use super::{
+        agent_permission_policy, allowed_tools_for_subagent, execute_agent_with_spawn,
+        execute_tool, final_assistant_text, mvp_tool_specs, persist_agent_terminal_state,
+        push_output_block, AgentInput, AgentJob, SubagentToolExecutor,
+    };
+    use api::OutputContentBlock;
+    use runtime::{ApiRequest, AssistantEvent, ConversationRuntime, RuntimeError, Session};
     use serde_json::json;
 
     fn env_lock() -> &'static Mutex<()> {
@@ -2587,6 +3125,63 @@ mod tests {
         assert!(error.contains("relative URL without a base") || error.contains("empty host"));
     }
 
+    #[test]
+    fn pending_tools_preserve_multiple_streaming_tool_calls_by_index() {
+        let mut events = Vec::new();
+        let mut pending_tools = BTreeMap::new();
+
+        push_output_block(
+            OutputContentBlock::ToolUse {
+                id: "tool-1".to_string(),
+                name: "read_file".to_string(),
+                input: json!({}),
+            },
+            1,
+            &mut events,
+            &mut pending_tools,
+            true,
+        );
+        push_output_block(
+            OutputContentBlock::ToolUse {
+                id: "tool-2".to_string(),
+                name: "grep_search".to_string(),
+                input: json!({}),
+            },
+            2,
+            &mut events,
+            &mut pending_tools,
+            true,
+        );
+
+        pending_tools
+            .get_mut(&1)
+            .expect("first tool pending")
+            .2
+            .push_str("{\"path\":\"src/main.rs\"}");
+        pending_tools
+            .get_mut(&2)
+            .expect("second tool pending")
+            .2
+            .push_str("{\"pattern\":\"TODO\"}");
+
+        assert_eq!(
+            pending_tools.remove(&1),
+            Some((
+                "tool-1".to_string(),
+                "read_file".to_string(),
+                "{\"path\":\"src/main.rs\"}".to_string(),
+            ))
+        );
+        assert_eq!(
+            pending_tools.remove(&2),
+            Some((
+                "tool-2".to_string(),
+                "grep_search".to_string(),
+                "{\"pattern\":\"TODO\"}".to_string(),
+            ))
+        );
+    }
+
     #[test]
     fn todo_write_persists_and_returns_previous_state() {
         let _guard = env_lock()
@@ -2765,32 +3360,48 @@ mod tests {
             .unwrap_or_else(std::sync::PoisonError::into_inner);
         let dir = temp_path("agent-store");
         std::env::set_var("CLAWD_AGENT_STORE", &dir);
+        let captured = Arc::new(Mutex::new(None::<AgentJob>));
+        let captured_for_spawn = Arc::clone(&captured);
 
-        let result = execute_tool(
+        let manifest = execute_agent_with_spawn(
-            "Agent",
+            AgentInput {
-            &json!({
+                description: "Audit the branch".to_string(),
-                "description": "Audit the branch",
+                prompt: "Check tests and outstanding work.".to_string(),
-                "prompt": "Check tests and outstanding work.",
+                subagent_type: Some("Explore".to_string()),
-                "subagent_type": "Explore",
+                name: Some("ship-audit".to_string()),
-                "name": "ship-audit"
+                model: None,
-            }),
+            },
+            move |job| {
+                *captured_for_spawn
+                    .lock()
+                    .unwrap_or_else(std::sync::PoisonError::into_inner) = Some(job);
+                Ok(())
+            },
         )
         .expect("Agent should succeed");
         std::env::remove_var("CLAWD_AGENT_STORE");
 
-        let output: serde_json::Value = serde_json::from_str(&result).expect("valid json");
+        assert_eq!(manifest.name, "ship-audit");
-        assert_eq!(output["name"], "ship-audit");
+        assert_eq!(manifest.subagent_type.as_deref(), Some("Explore"));
-        assert_eq!(output["subagentType"], "Explore");
+        assert_eq!(manifest.status, "running");
-        assert_eq!(output["status"], "queued");
+        assert!(!manifest.created_at.is_empty());
-        assert!(output["createdAt"].as_str().is_some());
+        assert!(manifest.started_at.is_some());
-        let manifest_file = output["manifestFile"].as_str().expect("manifest file");
+        assert!(manifest.completed_at.is_none());
-        let output_file = output["outputFile"].as_str().expect("output file");
+        let contents = std::fs::read_to_string(&manifest.output_file).expect("agent file exists");
-        let contents = std::fs::read_to_string(output_file).expect("agent file exists");
         let manifest_contents =
-            std::fs::read_to_string(manifest_file).expect("manifest file exists");
+            std::fs::read_to_string(&manifest.manifest_file).expect("manifest file exists");
         assert!(contents.contains("Audit the branch"));
         assert!(contents.contains("Check tests and outstanding work."));
         assert!(manifest_contents.contains("\"subagentType\": \"Explore\""));
+        assert!(manifest_contents.contains("\"status\": \"running\""));
+        let captured_job = captured
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner)
+            .clone()
+            .expect("spawn job should be captured");
+        assert_eq!(captured_job.prompt, "Check tests and outstanding work.");
+        assert!(captured_job.allowed_tools.contains("read_file"));
+        assert!(!captured_job.allowed_tools.contains("Agent"));
 
         let normalized = execute_tool(
             "Agent",
@@ -2819,6 +3430,195 @@ mod tests {
         let _ = std::fs::remove_dir_all(dir);
     }
 
+    #[test]
+    fn agent_fake_runner_can_persist_completion_and_failure() {
+        let _guard = env_lock()
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner);
+        let dir = temp_path("agent-runner");
+        std::env::set_var("CLAWD_AGENT_STORE", &dir);
+
+        let completed = execute_agent_with_spawn(
+            AgentInput {
+                description: "Complete the task".to_string(),
+                prompt: "Do the work".to_string(),
+                subagent_type: Some("Explore".to_string()),
+                name: Some("complete-task".to_string()),
+                model: Some("claude-sonnet-4-6".to_string()),
+            },
+            |job| {
+                persist_agent_terminal_state(
+                    &job.manifest,
+                    "completed",
+                    Some("Finished successfully"),
+                    None,
+                )
+            },
+        )
+        .expect("completed agent should succeed");
+
+        let completed_manifest = std::fs::read_to_string(&completed.manifest_file)
+            .expect("completed manifest should exist");
+        let completed_output =
+            std::fs::read_to_string(&completed.output_file).expect("completed output should exist");
+        assert!(completed_manifest.contains("\"status\": \"completed\""));
+        assert!(completed_output.contains("Finished successfully"));
+
+        let failed = execute_agent_with_spawn(
+            AgentInput {
+                description: "Fail the task".to_string(),
+                prompt: "Do the failing work".to_string(),
+                subagent_type: Some("Verification".to_string()),
+                name: Some("fail-task".to_string()),
+                model: None,
+            },
+            |job| {
+                persist_agent_terminal_state(
+                    &job.manifest,
+                    "failed",
+                    None,
+                    Some(String::from("simulated failure")),
+                )
+            },
+        )
+        .expect("failed agent should still spawn");
+
+        let failed_manifest =
+            std::fs::read_to_string(&failed.manifest_file).expect("failed manifest should exist");
+        let failed_output =
+            std::fs::read_to_string(&failed.output_file).expect("failed output should exist");
+        assert!(failed_manifest.contains("\"status\": \"failed\""));
+        assert!(failed_manifest.contains("simulated failure"));
+        assert!(failed_output.contains("simulated failure"));
+
+        let spawn_error = execute_agent_with_spawn(
+            AgentInput {
+                description: "Spawn error task".to_string(),
+                prompt: "Never starts".to_string(),
+                subagent_type: None,
+                name: Some("spawn-error".to_string()),
+                model: None,
+            },
+            |_| Err(String::from("thread creation failed")),
+        )
+        .expect_err("spawn errors should surface");
+        assert!(spawn_error.contains("failed to spawn sub-agent"));
+        let spawn_error_manifest = std::fs::read_dir(&dir)
+            .expect("agent dir should exist")
+            .filter_map(Result::ok)
+            .map(|entry| entry.path())
+            .filter(|path| path.extension().and_then(|ext| ext.to_str()) == Some("json"))
+            .find_map(|path| {
+                let contents = std::fs::read_to_string(&path).ok()?;
+                contents
+                    .contains("\"name\": \"spawn-error\"")
+                    .then_some(contents)
+            })
+            .expect("failed manifest should still be written");
+        assert!(spawn_error_manifest.contains("\"status\": \"failed\""));
+        assert!(spawn_error_manifest.contains("thread creation failed"));
+
+        std::env::remove_var("CLAWD_AGENT_STORE");
+        let _ = std::fs::remove_dir_all(dir);
+    }
+
+    #[test]
+    fn agent_tool_subset_mapping_is_expected() {
+        let general = allowed_tools_for_subagent("general-purpose");
+        assert!(general.contains("bash"));
+        assert!(general.contains("write_file"));
+        assert!(!general.contains("Agent"));
+
+        let explore = allowed_tools_for_subagent("Explore");
+        assert!(explore.contains("read_file"));
+        assert!(explore.contains("grep_search"));
+        assert!(!explore.contains("bash"));
+
+        let plan = allowed_tools_for_subagent("Plan");
+        assert!(plan.contains("TodoWrite"));
+        assert!(plan.contains("StructuredOutput"));
+        assert!(!plan.contains("Agent"));
+
+        let verification = allowed_tools_for_subagent("Verification");
+        assert!(verification.contains("bash"));
+        assert!(verification.contains("PowerShell"));
+        assert!(!verification.contains("write_file"));
+    }
+
+    #[derive(Debug)]
+    struct MockSubagentApiClient {
+        calls: usize,
+        input_path: String,
+    }
+
+    impl runtime::ApiClient for MockSubagentApiClient {
+        fn stream(&mut self, request: ApiRequest) -> Result<Vec<AssistantEvent>, RuntimeError> {
+            self.calls += 1;
+            match self.calls {
+                1 => {
+                    assert_eq!(request.messages.len(), 1);
+                    Ok(vec![
+                        AssistantEvent::ToolUse {
+                            id: "tool-1".to_string(),
+                            name: "read_file".to_string(),
+                            input: json!({ "path": self.input_path }).to_string(),
+                        },
+                        AssistantEvent::MessageStop,
+                    ])
+                }
+                2 => {
+                    assert!(request.messages.len() >= 3);
+                    Ok(vec![
+                        AssistantEvent::TextDelta("Scope: completed mock review".to_string()),
+                        AssistantEvent::MessageStop,
+                    ])
+                }
+                _ => panic!("unexpected mock stream call"),
+            }
+        }
+    }
+
+    #[test]
+    fn subagent_runtime_executes_tool_loop_with_isolated_session() {
+        let _guard = env_lock()
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner);
+        let path = temp_path("subagent-input.txt");
+        std::fs::write(&path, "hello from child").expect("write input file");
+
+        let mut runtime = ConversationRuntime::new(
+            Session::new(),
+            MockSubagentApiClient {
+                calls: 0,
+                input_path: path.display().to_string(),
+            },
+            SubagentToolExecutor::new(BTreeSet::from([String::from("read_file")])),
+            agent_permission_policy(),
+            vec![String::from("system prompt")],
+        );
+
+        let summary = runtime
+            .run_turn("Inspect the delegated file", None)
+            .expect("subagent loop should succeed");
+
+        assert_eq!(
+            final_assistant_text(&summary),
+            "Scope: completed mock review"
+        );
+        assert!(runtime
+            .session()
+            .messages
+            .iter()
+            .flat_map(|message| message.blocks.iter())
+            .any(|block| matches!(
+                block,
+                runtime::ContentBlock::ToolResult { output, .. }
+                    if output.contains("hello from child")
+            )));
+
+        let _ = std::fs::remove_file(path);
+    }
+
     #[test]
     fn agent_rejects_blank_required_fields() {
         let missing_description = execute_tool(