feat: make rusty-claude-cli usable end-to-end

Wire the CLI to the Anthropic client, runtime conversation loop, and MVP in-tree tool executor so prompt mode and the default REPL both execute real turns instead of scaffold-only commands.

Constraint: Proxy auth uses ANTHROPIC_AUTH_TOKEN as the primary x-api-key source and may stream extra usage fields
Constraint: Must preserve existing scaffold commands while enabling real prompt and REPL flows
Rejected: Keep prompt mode on the old scaffold path | does not satisfy end-to-end CLI requirement
Rejected: Depend solely on raw SSE message_stop from proxy | proxy/event differences required tolerant parsing plus fallback handling
Confidence: medium
Scope-risk: moderate
Reversibility: clean
Directive: Keep prompt mode tool-free unless the one-shot path is explicitly expanded and reverified against the proxy
Tested: cargo test -p api; cargo test -p tools; cargo test -p runtime; cargo test -p rusty-claude-cli; cargo build; cargo run -p rusty-claude-cli -- prompt "say hello"; printf '/quit\n' | cargo run -p rusty-claude-cli --
Not-tested: Full interactive tool_use roundtrip against the proxy in REPL mode

rust/crates/api/src/client.rs

@@ -41,14 +41,12 @@ impl AnthropicClient {
     }
 
     pub fn from_env() -> Result<Self, ApiError> {
-        Ok(Self::new(read_api_key(|key| std::env::var(key))?)
-            .with_auth_token(std::env::var("ANTHROPIC_AUTH_TOKEN").ok())
-            .with_base_url(
-                std::env::var("ANTHROPIC_BASE_URL")
-                    .ok()
-                    .or_else(|| std::env::var("CLAUDE_CODE_API_BASE_URL").ok())
-                    .unwrap_or_else(|| DEFAULT_BASE_URL.to_string()),
-            ))
+        Ok(Self::new(read_api_key()?).with_base_url(
+            std::env::var("ANTHROPIC_BASE_URL")
+                .ok()
+                .or_else(|| std::env::var("CLAUDE_CODE_API_BASE_URL").ok())
+                .unwrap_or_else(|| DEFAULT_BASE_URL.to_string()),
+        ))
     }
 
     #[must_use]
@@ -187,13 +185,16 @@ impl AnthropicClient {
     }
 }
 
-fn read_api_key(
-    getter: impl FnOnce(&str) -> Result<String, std::env::VarError>,
-) -> Result<String, ApiError> {
-    match getter("ANTHROPIC_API_KEY") {
-        Ok(api_key) if api_key.is_empty() => Err(ApiError::MissingApiKey),
-        Ok(api_key) => Ok(api_key),
-        Err(std::env::VarError::NotPresent) => Err(ApiError::MissingApiKey),
+fn read_api_key() -> Result<String, ApiError> {
+    match std::env::var("ANTHROPIC_AUTH_TOKEN") {
+        Ok(api_key) if !api_key.is_empty() => Ok(api_key),
+        Ok(_) => Err(ApiError::MissingApiKey),
+        Err(std::env::VarError::NotPresent) => match std::env::var("ANTHROPIC_API_KEY") {
+            Ok(api_key) if !api_key.is_empty() => Ok(api_key),
+            Ok(_) => Err(ApiError::MissingApiKey),
+            Err(std::env::VarError::NotPresent) => Err(ApiError::MissingApiKey),
+            Err(error) => Err(ApiError::from(error)),
+        },
         Err(error) => Err(ApiError::from(error)),
     }
 }
@@ -289,8 +290,6 @@ struct AnthropicErrorBody {
 
 #[cfg(test)]
 mod tests {
-    use std::env::VarError;
-
     use super::{ALT_REQUEST_ID_HEADER, REQUEST_ID_HEADER};
     use std::time::Duration;
 
@@ -298,21 +297,30 @@ mod tests {
 
     #[test]
     fn read_api_key_requires_presence() {
-        let error = super::read_api_key(|_| Err(VarError::NotPresent))
-            .expect_err("missing key should error");
+        std::env::remove_var("ANTHROPIC_AUTH_TOKEN");
+        std::env::remove_var("ANTHROPIC_API_KEY");
+        let error = super::read_api_key().expect_err("missing key should error");
         assert!(matches!(error, crate::error::ApiError::MissingApiKey));
     }
 
     #[test]
     fn read_api_key_requires_non_empty_value() {
-        let error = super::read_api_key(|_| Ok(String::new())).expect_err("empty key should error");
+        std::env::set_var("ANTHROPIC_AUTH_TOKEN", "");
+        std::env::remove_var("ANTHROPIC_API_KEY");
+        let error = super::read_api_key().expect_err("empty key should error");
         assert!(matches!(error, crate::error::ApiError::MissingApiKey));
     }
 
     #[test]
-    fn with_auth_token_drops_empty_values() {
-        let client = super::AnthropicClient::new("test-key").with_auth_token(Some(String::new()));
-        assert!(client.auth_token.is_none());
+    fn read_api_key_prefers_auth_token() {
+        std::env::set_var("ANTHROPIC_AUTH_TOKEN", "auth-token");
+        std::env::set_var("ANTHROPIC_API_KEY", "legacy-key");
+        assert_eq!(
+            super::read_api_key().expect("token should load"),
+            "auth-token"
+        );
+        std::env::remove_var("ANTHROPIC_AUTH_TOKEN");
+        std::env::remove_var("ANTHROPIC_API_KEY");
     }
 
     #[test]

rust/crates/api/src/error.rs

@@ -50,11 +50,14 @@ impl Display for ApiError {
             Self::MissingApiKey => {
                 write!(
                     f,
-                    "ANTHROPIC_API_KEY is not set; export it before calling the Anthropic API"
+                    "ANTHROPIC_AUTH_TOKEN or ANTHROPIC_API_KEY is not set; export one before calling the Anthropic API"
                 )
             }
             Self::InvalidApiKeyEnv(error) => {
-                write!(f, "failed to read ANTHROPIC_API_KEY: {error}")
+                write!(
+                    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}"),

rust/crates/api/src/sse.rs

@@ -178,6 +178,8 @@ mod tests {
                     },
                     usage: Usage {
                         input_tokens: 1,
+                        cache_creation_input_tokens: 0,
+                        cache_read_input_tokens: 0,
                         output_tokens: 2,
                     },
                 }),

rust/crates/api/src/types.rs

@@ -64,6 +64,11 @@ pub enum InputContentBlock {
     Text {
         text: String,
     },
+    ToolUse {
+        id: String,
+        name: String,
+        input: Value,
+    },
     ToolResult {
         tool_use_id: String,
         content: Vec<ToolResultContentBlock>,
@@ -135,6 +140,10 @@ pub enum OutputContentBlock {
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 pub struct Usage {
     pub input_tokens: u32,
+    #[serde(default)]
+    pub cache_creation_input_tokens: u32,
+    #[serde(default)]
+    pub cache_read_input_tokens: u32,
     pub output_tokens: u32,
 }
 

rust/crates/runtime/Cargo.toml

@@ -5,5 +5,13 @@ edition.workspace = true
 license.workspace = true
 publish.workspace = true
 
+[dependencies]
+glob = "0.3"
+regex = "1"
+serde = { version = "1", features = ["derive"] }
+serde_json = "1"
+tokio = { version = "1", features = ["macros", "process", "rt", "rt-multi-thread", "time"] }
+walkdir = "2"
+
 [lints]
 workspace = true

rust/crates/runtime/src/file_ops.rs

@@ -129,7 +129,11 @@ pub struct GrepSearchOutput {
     pub applied_offset: Option<usize>,
 }
 
-pub fn read_file(path: &str, offset: Option<usize>, limit: Option<usize>) -> io::Result<ReadFileOutput> {
+pub fn read_file(
+    path: &str,
+    offset: Option<usize>,
+    limit: Option<usize>,
+) -> io::Result<ReadFileOutput> {
     let absolute_path = normalize_path(path)?;
     let content = fs::read_to_string(&absolute_path)?;
     let lines: Vec<&str> = content.lines().collect();
@@ -173,14 +177,25 @@ pub fn write_file(path: &str, content: &str) -> io::Result<WriteFileOutput> {
     })
 }
 
-pub fn edit_file(path: &str, old_string: &str, new_string: &str, replace_all: bool) -> io::Result<EditFileOutput> {
+pub fn edit_file(
+    path: &str,
+    old_string: &str,
+    new_string: &str,
+    replace_all: bool,
+) -> io::Result<EditFileOutput> {
     let absolute_path = normalize_path(path)?;
     let original_file = fs::read_to_string(&absolute_path)?;
     if old_string == new_string {
-        return Err(io::Error::new(io::ErrorKind::InvalidInput, "old_string and new_string must differ"));
+        return Err(io::Error::new(
+            io::ErrorKind::InvalidInput,
+            "old_string and new_string must differ",
+        ));
     }
     if !original_file.contains(old_string) {
-        return Err(io::Error::new(io::ErrorKind::NotFound, "old_string not found in file"));
+        return Err(io::Error::new(
+            io::ErrorKind::NotFound,
+            "old_string not found in file",
+        ));
     }
 
     let updated = if replace_all {
@@ -204,7 +219,10 @@ pub fn edit_file(path: &str, old_string: &str, new_string: &str, replace_all: bo
 
 pub fn glob_search(pattern: &str, path: Option<&str>) -> io::Result<GlobSearchOutput> {
     let started = Instant::now();
-    let base_dir = path.map(normalize_path).transpose()?.unwrap_or(std::env::current_dir()?);
+    let base_dir = path
+        .map(normalize_path)
+        .transpose()?
+        .unwrap_or(std::env::current_dir()?);
     let search_pattern = if Path::new(pattern).is_absolute() {
         pattern.to_owned()
     } else {
@@ -212,7 +230,8 @@ pub fn glob_search(pattern: &str, path: Option<&str>) -> io::Result<GlobSearchOu
     };
 
     let mut matches = Vec::new();
-    let entries = glob::glob(&search_pattern).map_err(|error| io::Error::new(io::ErrorKind::InvalidInput, error.to_string()))?;
+    let entries = glob::glob(&search_pattern)
+        .map_err(|error| io::Error::new(io::ErrorKind::InvalidInput, error.to_string()))?;
     for entry in entries.flatten() {
         if entry.is_file() {
             matches.push(entry);
@@ -255,9 +274,17 @@ pub fn grep_search(input: &GrepSearchInput) -> io::Result<GrepSearchOutput> {
         .build()
         .map_err(|error| io::Error::new(io::ErrorKind::InvalidInput, error.to_string()))?;
 
-    let glob_filter = input.glob.as_deref().map(Pattern::new).transpose().map_err(|error| io::Error::new(io::ErrorKind::InvalidInput, error.to_string()))?;
+    let glob_filter = input
+        .glob
+        .as_deref()
+        .map(Pattern::new)
+        .transpose()
+        .map_err(|error| io::Error::new(io::ErrorKind::InvalidInput, error.to_string()))?;
     let file_type = input.file_type.as_deref();
-    let output_mode = input.output_mode.clone().unwrap_or_else(|| String::from("files_with_matches"));
+    let output_mode = input
+        .output_mode
+        .clone()
+        .unwrap_or_else(|| String::from("files_with_matches"));
     let context = input.context.or(input.context_short).unwrap_or(0);
 
     let mut filenames = Vec::new();
@@ -312,7 +339,8 @@ pub fn grep_search(input: &GrepSearchInput) -> io::Result<GrepSearchOutput> {
         }
     }
 
-    let (filenames, applied_limit, applied_offset) = apply_limit(filenames, input.head_limit, input.offset);
+    let (filenames, applied_limit, applied_offset) =
+        apply_limit(filenames, input.head_limit, input.offset);
     let content = if output_mode == "content" {
         let (lines, limit, offset) = apply_limit(content_lines, input.head_limit, input.offset);
         return Ok(GrepSearchOutput {
@@ -348,7 +376,8 @@ fn collect_search_files(base_path: &Path) -> io::Result<Vec<PathBuf>> {
 
     let mut files = Vec::new();
     for entry in WalkDir::new(base_path) {
-        let entry = entry.map_err(|error| io::Error::new(io::ErrorKind::Other, error.to_string()))?;
+        let entry =
+            entry.map_err(|error| io::Error::new(io::ErrorKind::Other, error.to_string()))?;
         if entry.file_type().is_file() {
             files.push(entry.path().to_path_buf());
         }
@@ -356,7 +385,11 @@ fn collect_search_files(base_path: &Path) -> io::Result<Vec<PathBuf>> {
     Ok(files)
 }
 
-fn matches_optional_filters(path: &Path, glob_filter: Option<&Pattern>, file_type: Option<&str>) -> bool {
+fn matches_optional_filters(
+    path: &Path,
+    glob_filter: Option<&Pattern>,
+    file_type: Option<&str>,
+) -> bool {
     if let Some(glob_filter) = glob_filter {
         let path_string = path.to_string_lossy();
         if !glob_filter.matches(&path_string) && !glob_filter.matches_path(path) {
@@ -374,7 +407,11 @@ fn matches_optional_filters(path: &Path, glob_filter: Option<&Pattern>, file_typ
     true
 }
 
-fn apply_limit<T>(items: Vec<T>, limit: Option<usize>, offset: Option<usize>) -> (Vec<T>, Option<usize>, Option<usize>) {
+fn apply_limit<T>(
+    items: Vec<T>,
+    limit: Option<usize>,
+    offset: Option<usize>,
+) -> (Vec<T>, Option<usize>, Option<usize>) {
     let offset_value = offset.unwrap_or(0);
     let mut items = items.into_iter().skip(offset_value).collect::<Vec<_>>();
     let explicit_limit = limit.unwrap_or(250);
@@ -430,7 +467,9 @@ fn normalize_path_allow_missing(path: &str) -> io::Result<PathBuf> {
     }
 
     if let Some(parent) = candidate.parent() {
-        let canonical_parent = parent.canonicalize().unwrap_or_else(|_| parent.to_path_buf());
+        let canonical_parent = parent
+            .canonicalize()
+            .unwrap_or_else(|_| parent.to_path_buf());
         if let Some(name) = candidate.file_name() {
             return Ok(canonical_parent.join(name));
         }
@@ -456,18 +495,22 @@ mod tests {
     #[test]
     fn reads_and_writes_files() {
         let path = temp_path("read-write.txt");
-        let write_output = write_file(path.to_string_lossy().as_ref(), "one\ntwo\nthree").expect("write should succeed");
+        let write_output = write_file(path.to_string_lossy().as_ref(), "one\ntwo\nthree")
+            .expect("write should succeed");
         assert_eq!(write_output.kind, "create");
 
-        let read_output = read_file(path.to_string_lossy().as_ref(), Some(1), Some(1)).expect("read should succeed");
+        let read_output = read_file(path.to_string_lossy().as_ref(), Some(1), Some(1))
+            .expect("read should succeed");
         assert_eq!(read_output.file.content, "two");
     }
 
     #[test]
     fn edits_file_contents() {
         let path = temp_path("edit.txt");
-        write_file(path.to_string_lossy().as_ref(), "alpha beta alpha").expect("initial write should succeed");
-        let output = edit_file(path.to_string_lossy().as_ref(), "alpha", "omega", true).expect("edit should succeed");
+        write_file(path.to_string_lossy().as_ref(), "alpha beta alpha")
+            .expect("initial write should succeed");
+        let output = edit_file(path.to_string_lossy().as_ref(), "alpha", "omega", true)
+            .expect("edit should succeed");
         assert!(output.replace_all);
     }
 
@@ -476,9 +519,14 @@ mod tests {
         let dir = temp_path("search-dir");
         std::fs::create_dir_all(&dir).expect("directory should be created");
         let file = dir.join("demo.rs");
-        write_file(file.to_string_lossy().as_ref(), "fn main() {\n println!(\"hello\");\n}\n").expect("file write should succeed");
+        write_file(
+            file.to_string_lossy().as_ref(),
+            "fn main() {\n println!(\"hello\");\n}\n",
+        )
+        .expect("file write should succeed");
 
-        let globbed = glob_search("**/*.rs", Some(dir.to_string_lossy().as_ref())).expect("glob should succeed");
+        let globbed = glob_search("**/*.rs", Some(dir.to_string_lossy().as_ref()))
+            .expect("glob should succeed");
         assert_eq!(globbed.num_files, 1);
 
         let grep_output = grep_search(&GrepSearchInput {

rust/crates/runtime/src/lib.rs

@@ -1,13 +1,16 @@
+mod bash;
 mod bootstrap;
 mod compact;
 mod config;
 mod conversation;
+mod file_ops;
 mod json;
 mod permissions;
 mod prompt;
 mod session;
 mod usage;
 
+pub use bash::{execute_bash, BashCommandInput, BashCommandOutput};
 pub use bootstrap::{BootstrapPhase, BootstrapPlan};
 pub use compact::{
     compact_session, estimate_session_tokens, format_compact_summary,
@@ -21,6 +24,11 @@ pub use conversation::{
     ApiClient, ApiRequest, AssistantEvent, ConversationRuntime, RuntimeError, StaticToolExecutor,
     ToolError, ToolExecutor, TurnSummary,
 };
+pub use file_ops::{
+    edit_file, glob_search, grep_search, read_file, write_file, EditFileOutput, GlobSearchOutput,
+    GrepSearchInput, GrepSearchOutput, ReadFileOutput, StructuredPatchHunk, TextFilePayload,
+    WriteFileOutput,
+};
 pub use permissions::{
     PermissionMode, PermissionOutcome, PermissionPolicy, PermissionPromptDecision,
     PermissionPrompter, PermissionRequest,

rust/crates/rusty-claude-cli/Cargo.toml

@@ -6,9 +6,16 @@ license.workspace = true
 publish.workspace = true
 
 [dependencies]
+api = { path = "../api" }
 commands = { path = "../commands" }
 compat-harness = { path = "../compat-harness" }
+crossterm = "0.28"
+pulldown-cmark = "0.13"
 runtime = { path = "../runtime" }
+serde_json = "1"
+syntect = "5"
+tokio = { version = "1", features = ["rt-multi-thread", "time"] }
+tools = { path = "../tools" }
 
 [lints]
 workspace = true

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

@@ -1,4 +1,4 @@
-use std::io::{self, Write};
+use std::io::{self, IsTerminal, Write};
 
 use crossterm::cursor::MoveToColumn;
 use crossterm::event::{self, Event, KeyCode, KeyEvent, KeyModifiers};
@@ -100,6 +100,10 @@ impl LineEditor {
     }
 
     pub fn read_line(&self) -> io::Result<Option<String>> {
+        if !io::stdin().is_terminal() || !io::stdout().is_terminal() {
+            return self.read_line_fallback();
+        }
+
         enable_raw_mode()?;
         let mut stdout = io::stdout();
         let mut input = InputBuffer::new();
@@ -125,6 +129,23 @@ impl LineEditor {
         }
     }
 
+    fn read_line_fallback(&self) -> io::Result<Option<String>> {
+        let mut stdout = io::stdout();
+        write!(stdout, "{}", self.prompt)?;
+        stdout.flush()?;
+
+        let mut buffer = String::new();
+        let bytes_read = io::stdin().read_line(&mut buffer)?;
+        if bytes_read == 0 {
+            return Ok(None);
+        }
+
+        while matches!(buffer.chars().last(), Some('\n' | '\r')) {
+            buffer.pop();
+        }
+        Ok(Some(buffer))
+    }
+
     fn handle_key(key: KeyEvent, input: &mut InputBuffer) -> EditorAction {
         match key {
             KeyEvent {

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

@@ -1,28 +1,52 @@
+mod input;
+mod render;
+
 use std::env;
+use std::io::{self, Write};
 use std::path::{Path, PathBuf};
 
+use api::{
+    AnthropicClient, ContentBlockDelta, InputContentBlock, InputMessage, MessageRequest,
+    MessageResponse, OutputContentBlock, StreamEvent as ApiStreamEvent, ToolChoice, ToolDefinition,
+    ToolResultContentBlock,
+};
+
 use commands::handle_slash_command;
 use compat_harness::{extract_manifest, UpstreamPaths};
-use runtime::{load_system_prompt, BootstrapPlan, CompactionConfig, Session};
+use render::{Spinner, TerminalRenderer};
+use runtime::{
+    load_system_prompt, ApiClient, ApiRequest, AssistantEvent, CompactionConfig, ContentBlock,
+    ConversationMessage, ConversationRuntime, MessageRole, PermissionMode, PermissionPolicy,
+    RuntimeError, Session, TokenUsage, ToolError, ToolExecutor,
+};
+use tools::{execute_tool, mvp_tool_specs};
+
+const DEFAULT_MODEL: &str = "claude-sonnet-4-20250514";
+const DEFAULT_MAX_TOKENS: u32 = 32;
+const DEFAULT_DATE: &str = "2026-03-31";
 
 fn main() {
-    let args: Vec<String> = env::args().skip(1).collect();
+    if let Err(error) = run() {
+        eprintln!("{error}");
+        std::process::exit(1);
+    }
+}
 
-    match parse_args(&args) {
-        Ok(CliAction::DumpManifests) => dump_manifests(),
-        Ok(CliAction::BootstrapPlan) => print_bootstrap_plan(),
-        Ok(CliAction::PrintSystemPrompt { cwd, date }) => print_system_prompt(cwd, date),
-        Ok(CliAction::ResumeSession {
+fn run() -> Result<(), Box<dyn std::error::Error>> {
+    let args: Vec<String> = env::args().skip(1).collect();
+    match parse_args(&args)? {
+        CliAction::DumpManifests => dump_manifests(),
+        CliAction::BootstrapPlan => print_bootstrap_plan(),
+        CliAction::PrintSystemPrompt { cwd, date } => print_system_prompt(cwd, date),
+        CliAction::ResumeSession {
             session_path,
             command,
-        }) => resume_session(&session_path, command),
-        Ok(CliAction::Help) => print_help(),
-        Err(error) => {
-            eprintln!("{error}");
-            print_help();
-            std::process::exit(2);
-        }
+        } => resume_session(&session_path, command),
+        CliAction::Prompt { prompt, model } => LiveCli::new(model, false)?.run_turn(&prompt)?,
+        CliAction::Repl { model } => run_repl(model)?,
+        CliAction::Help => print_help(),
     }
+    Ok(())
 }
 
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -37,33 +61,69 @@ enum CliAction {
         session_path: PathBuf,
         command: Option<String>,
     },
+    Prompt {
+        prompt: String,
+        model: String,
+    },
+    Repl {
+        model: String,
+    },
     Help,
 }
 
 fn parse_args(args: &[String]) -> Result<CliAction, String> {
-    if args.is_empty() {
+    let mut model = DEFAULT_MODEL.to_string();
+    let mut rest = Vec::new();
+    let mut index = 0;
+
+    while index < args.len() {
+        match args[index].as_str() {
+            "--model" => {
+                let value = args
+                    .get(index + 1)
+                    .ok_or_else(|| "missing value for --model".to_string())?;
+                model = value.clone();
+                index += 2;
+            }
+            flag if flag.starts_with("--model=") => {
+                model = flag[8..].to_string();
+                index += 1;
+            }
+            other => {
+                rest.push(other.to_string());
+                index += 1;
+            }
+        }
+    }
+
+    if rest.is_empty() {
+        return Ok(CliAction::Repl { model });
+    }
+    if matches!(rest.first().map(String::as_str), Some("--help" | "-h")) {
         return Ok(CliAction::Help);
     }
-
-    if matches!(args.first().map(String::as_str), Some("--help" | "-h")) {
-        return Ok(CliAction::Help);
+    if rest.first().map(String::as_str) == Some("--resume") {
+        return parse_resume_args(&rest[1..]);
     }
 
-    if args.first().map(String::as_str) == Some("--resume") {
-        return parse_resume_args(&args[1..]);
-    }
-
-    match args[0].as_str() {
+    match rest[0].as_str() {
         "dump-manifests" => Ok(CliAction::DumpManifests),
         "bootstrap-plan" => Ok(CliAction::BootstrapPlan),
-        "system-prompt" => parse_system_prompt_args(&args[1..]),
+        "system-prompt" => parse_system_prompt_args(&rest[1..]),
+        "prompt" => {
+            let prompt = rest[1..].join(" ");
+            if prompt.trim().is_empty() {
+                return Err("prompt subcommand requires a prompt string".to_string());
+            }
+            Ok(CliAction::Prompt { prompt, model })
+        }
         other => Err(format!("unknown subcommand: {other}")),
     }
 }
 
 fn parse_system_prompt_args(args: &[String]) -> Result<CliAction, String> {
     let mut cwd = env::current_dir().map_err(|error| error.to_string())?;
-    let mut date = "2026-03-31".to_string();
+    let mut date = DEFAULT_DATE.to_string();
     let mut index = 0;
 
     while index < args.len() {
@@ -121,7 +181,7 @@ fn dump_manifests() {
 }
 
 fn print_bootstrap_plan() {
-    for phase in BootstrapPlan::claude_code_default().phases() {
+    for phase in runtime::BootstrapPlan::claude_code_default().phases() {
         println!("- {phase:?}");
     }
 }
@@ -178,24 +238,444 @@ fn resume_session(session_path: &Path, command: Option<String>) {
     }
 }
 
+fn run_repl(model: String) -> Result<(), Box<dyn std::error::Error>> {
+    let mut cli = LiveCli::new(model, true)?;
+    let editor = input::LineEditor::new("› ");
+    println!("Rusty Claude CLI interactive mode");
+    println!("Type /help for commands. Shift+Enter or Ctrl+J inserts a newline.");
+
+    while let Some(input) = editor.read_line()? {
+        let trimmed = input.trim();
+        if trimmed.is_empty() {
+            continue;
+        }
+        match trimmed {
+            "/exit" | "/quit" => break,
+            "/help" => {
+                println!("Available commands:");
+                println!("  /help    Show help");
+                println!("  /status  Show session status");
+                println!("  /compact Compact session history");
+                println!("  /exit    Quit the REPL");
+            }
+            "/status" => cli.print_status(),
+            "/compact" => cli.compact()?,
+            _ => cli.run_turn(trimmed)?,
+        }
+    }
+
+    Ok(())
+}
+
+struct LiveCli {
+    model: String,
+    system_prompt: Vec<String>,
+    runtime: ConversationRuntime<AnthropicRuntimeClient, CliToolExecutor>,
+}
+
+impl LiveCli {
+    fn new(model: String, enable_tools: bool) -> Result<Self, Box<dyn std::error::Error>> {
+        let system_prompt = build_system_prompt()?;
+        let runtime = build_runtime(
+            Session::new(),
+            model.clone(),
+            system_prompt.clone(),
+            enable_tools,
+        )?;
+        Ok(Self {
+            model,
+            system_prompt,
+            runtime,
+        })
+    }
+
+    fn run_turn(&mut self, input: &str) -> Result<(), Box<dyn std::error::Error>> {
+        let mut spinner = Spinner::new();
+        let mut stdout = io::stdout();
+        spinner.tick(
+            "Waiting for Claude",
+            TerminalRenderer::new().color_theme(),
+            &mut stdout,
+        )?;
+        let result = self.runtime.run_turn(input, None);
+        match result {
+            Ok(_) => {
+                spinner.finish(
+                    "Claude response complete",
+                    TerminalRenderer::new().color_theme(),
+                    &mut stdout,
+                )?;
+                println!();
+                Ok(())
+            }
+            Err(error) => {
+                spinner.fail(
+                    "Claude request failed",
+                    TerminalRenderer::new().color_theme(),
+                    &mut stdout,
+                )?;
+                Err(Box::new(error))
+            }
+        }
+    }
+
+    fn print_status(&self) {
+        let usage = self.runtime.usage().cumulative_usage();
+        println!(
+            "status: messages={} turns={} input_tokens={} output_tokens={}",
+            self.runtime.session().messages.len(),
+            self.runtime.usage().turns(),
+            usage.input_tokens,
+            usage.output_tokens
+        );
+    }
+
+    fn compact(&mut self) -> Result<(), Box<dyn std::error::Error>> {
+        let result = self.runtime.compact(CompactionConfig::default());
+        let removed = result.removed_message_count;
+        self.runtime = build_runtime(
+            result.compacted_session,
+            self.model.clone(),
+            self.system_prompt.clone(),
+            true,
+        )?;
+        println!("Compacted {removed} messages.");
+        Ok(())
+    }
+}
+
+fn build_system_prompt() -> Result<Vec<String>, Box<dyn std::error::Error>> {
+    Ok(load_system_prompt(
+        env::current_dir()?,
+        DEFAULT_DATE,
+        env::consts::OS,
+        "unknown",
+    )?)
+}
+
+fn build_runtime(
+    session: Session,
+    model: String,
+    system_prompt: Vec<String>,
+    enable_tools: bool,
+) -> Result<ConversationRuntime<AnthropicRuntimeClient, CliToolExecutor>, Box<dyn std::error::Error>>
+{
+    Ok(ConversationRuntime::new(
+        session,
+        AnthropicRuntimeClient::new(model, enable_tools)?,
+        CliToolExecutor::new(),
+        permission_policy_from_env(),
+        system_prompt,
+    ))
+}
+
+struct AnthropicRuntimeClient {
+    runtime: tokio::runtime::Runtime,
+    client: AnthropicClient,
+    model: String,
+    enable_tools: bool,
+}
+
+impl AnthropicRuntimeClient {
+    fn new(model: String, enable_tools: bool) -> Result<Self, Box<dyn std::error::Error>> {
+        Ok(Self {
+            runtime: tokio::runtime::Runtime::new()?,
+            client: AnthropicClient::from_env()?,
+            model,
+            enable_tools,
+        })
+    }
+}
+
+impl ApiClient for AnthropicRuntimeClient {
+    fn stream(&mut self, request: ApiRequest) -> Result<Vec<AssistantEvent>, RuntimeError> {
+        let message_request = MessageRequest {
+            model: self.model.clone(),
+            max_tokens: DEFAULT_MAX_TOKENS,
+            messages: convert_messages(&request.messages),
+            system: (!request.system_prompt.is_empty()).then(|| request.system_prompt.join("\n\n")),
+            tools: self.enable_tools.then(|| {
+                mvp_tool_specs()
+                    .into_iter()
+                    .map(|spec| ToolDefinition {
+                        name: spec.name.to_string(),
+                        description: Some(spec.description.to_string()),
+                        input_schema: spec.input_schema,
+                    })
+                    .collect()
+            }),
+            tool_choice: self.enable_tools.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 stdout = io::stdout();
+            let mut events = Vec::new();
+            let mut pending_tool: Option<(String, String, String)> = None;
+            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, &mut stdout, &mut events, &mut pending_tool)?;
+                        }
+                    }
+                    ApiStreamEvent::ContentBlockStart(start) => {
+                        push_output_block(
+                            start.content_block,
+                            &mut stdout,
+                            &mut events,
+                            &mut pending_tool,
+                        )?;
+                    }
+                    ApiStreamEvent::ContentBlockDelta(delta) => match delta.delta {
+                        ContentBlockDelta::TextDelta { text } => {
+                            if !text.is_empty() {
+                                write!(stdout, "{text}")
+                                    .and_then(|_| stdout.flush())
+                                    .map_err(|error| RuntimeError::new(error.to_string()))?;
+                                events.push(AssistantEvent::TextDelta(text));
+                            }
+                        }
+                        ContentBlockDelta::InputJsonDelta { partial_json } => {
+                            if let Some((_, _, input)) = &mut pending_tool {
+                                input.push_str(&partial_json);
+                            }
+                        }
+                    },
+                    ApiStreamEvent::ContentBlockStop(_) => {
+                        if let Some((id, name, input)) = pending_tool.take() {
+                            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()))?;
+            response_to_events(response, &mut stdout)
+        })
+    }
+}
+
+fn push_output_block(
+    block: OutputContentBlock,
+    out: &mut impl Write,
+    events: &mut Vec<AssistantEvent>,
+    pending_tool: &mut Option<(String, String, String)>,
+) -> Result<(), RuntimeError> {
+    match block {
+        OutputContentBlock::Text { text } => {
+            if !text.is_empty() {
+                write!(out, "{text}")
+                    .and_then(|_| out.flush())
+                    .map_err(|error| RuntimeError::new(error.to_string()))?;
+                events.push(AssistantEvent::TextDelta(text));
+            }
+        }
+        OutputContentBlock::ToolUse { id, name, input } => {
+            *pending_tool = Some((id, name, input.to_string()));
+        }
+    }
+    Ok(())
+}
+
+fn response_to_events(
+    response: MessageResponse,
+    out: &mut impl Write,
+) -> Result<Vec<AssistantEvent>, RuntimeError> {
+    let mut events = Vec::new();
+    let mut pending_tool = None;
+
+    for block in response.content {
+        push_output_block(block, out, &mut events, &mut pending_tool)?;
+        if let Some((id, name, input)) = pending_tool.take() {
+            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);
+    Ok(events)
+}
+
+struct CliToolExecutor {
+    renderer: TerminalRenderer,
+}
+
+impl CliToolExecutor {
+    fn new() -> Self {
+        Self {
+            renderer: TerminalRenderer::new(),
+        }
+    }
+}
+
+impl ToolExecutor for CliToolExecutor {
+    fn execute(&mut self, tool_name: &str, input: &str) -> Result<String, ToolError> {
+        let value = serde_json::from_str(input)
+            .map_err(|error| ToolError::new(format!("invalid tool input JSON: {error}")))?;
+        match execute_tool(tool_name, &value) {
+            Ok(output) => {
+                let markdown = format!("### Tool `{tool_name}`\n\n```json\n{output}\n```\n");
+                self.renderer
+                    .stream_markdown(&markdown, &mut io::stdout())
+                    .map_err(|error| ToolError::new(error.to_string()))?;
+                Ok(output)
+            }
+            Err(error) => Err(ToolError::new(error)),
+        }
+    }
+}
+
+fn permission_policy_from_env() -> PermissionPolicy {
+    let mode =
+        env::var("RUSTY_CLAUDE_PERMISSION_MODE").unwrap_or_else(|_| "workspace-write".to_string());
+    match mode.as_str() {
+        "read-only" => PermissionPolicy::new(PermissionMode::Deny)
+            .with_tool_mode("read_file", PermissionMode::Allow)
+            .with_tool_mode("glob_search", PermissionMode::Allow)
+            .with_tool_mode("grep_search", PermissionMode::Allow),
+        _ => PermissionPolicy::new(PermissionMode::Allow),
+    }
+}
+
+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 print_help() {
     println!("rusty-claude-cli");
     println!();
-    println!("Current scaffold commands:");
+    println!("Usage:");
+    println!("  rusty-claude-cli [--model MODEL]             Start interactive REPL");
     println!(
-        "  dump-manifests                   Read upstream TS sources and print extracted counts"
+        "  rusty-claude-cli [--model MODEL] prompt TEXT Send one prompt and stream the response"
     );
-    println!("  bootstrap-plan                   Print the current bootstrap phase skeleton");
-    println!("  system-prompt [--cwd PATH] [--date YYYY-MM-DD]");
-    println!("                                   Build a Claude-style system prompt from CLAUDE.md and config files");
-    println!("  --resume SESSION.json [/compact] Restore a saved session and optionally run a slash command");
+    println!("  rusty-claude-cli dump-manifests");
+    println!("  rusty-claude-cli bootstrap-plan");
+    println!("  rusty-claude-cli system-prompt [--cwd PATH] [--date YYYY-MM-DD]");
+    println!("  rusty-claude-cli --resume SESSION.json [/compact]");
 }
 
 #[cfg(test)]
 mod tests {
-    use super::{parse_args, CliAction};
+    use super::{parse_args, CliAction, DEFAULT_MODEL};
+    use runtime::{ContentBlock, ConversationMessage, MessageRole};
     use std::path::PathBuf;
 
+    #[test]
+    fn defaults_to_repl_when_no_args() {
+        assert_eq!(
+            parse_args(&[]).expect("args should parse"),
+            CliAction::Repl {
+                model: DEFAULT_MODEL.to_string(),
+            }
+        );
+    }
+
+    #[test]
+    fn parses_prompt_subcommand() {
+        let args = vec![
+            "prompt".to_string(),
+            "hello".to_string(),
+            "world".to_string(),
+        ];
+        assert_eq!(
+            parse_args(&args).expect("args should parse"),
+            CliAction::Prompt {
+                prompt: "hello world".to_string(),
+                model: DEFAULT_MODEL.to_string(),
+            }
+        );
+    }
+
     #[test]
     fn parses_system_prompt_options() {
         let args = vec![
@@ -229,4 +709,31 @@ mod tests {
             }
         );
     }
+
+    #[test]
+    fn converts_tool_roundtrip_messages() {
+        let messages = vec![
+            ConversationMessage::user_text("hello"),
+            ConversationMessage::assistant(vec![ContentBlock::ToolUse {
+                id: "tool-1".to_string(),
+                name: "bash".to_string(),
+                input: "{\"command\":\"pwd\"}".to_string(),
+            }]),
+            ConversationMessage {
+                role: MessageRole::Tool,
+                blocks: vec![ContentBlock::ToolResult {
+                    tool_use_id: "tool-1".to_string(),
+                    tool_name: "bash".to_string(),
+                    output: "ok".to_string(),
+                    is_error: false,
+                }],
+                usage: None,
+            },
+        ];
+
+        let converted = super::convert_messages(&messages);
+        assert_eq!(converted.len(), 3);
+        assert_eq!(converted[1].role, "assistant");
+        assert_eq!(converted[2].role, "user");
+    }
 }

rust/crates/tools/Cargo.toml

@@ -5,5 +5,10 @@ edition.workspace = true
 license.workspace = true
 publish.workspace = true
 
+[dependencies]
+runtime = { path = "../runtime" }
+serde = { version = "1", features = ["derive"] }
+serde_json = "1"
+
 [lints]
 workspace = true

rust/crates/tools/src/lib.rs

@@ -1,3 +1,10 @@
+use runtime::{
+    edit_file, execute_bash, glob_search, grep_search, read_file, write_file, BashCommandInput,
+    GrepSearchInput,
+};
+use serde::Deserialize;
+use serde_json::{json, Value};
+
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct ToolManifestEntry {
     pub name: String,
@@ -26,3 +33,218 @@ impl ToolRegistry {
         &self.entries
     }
 }
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct ToolSpec {
+    pub name: &'static str,
+    pub description: &'static str,
+    pub input_schema: Value,
+}
+
+#[must_use]
+pub fn mvp_tool_specs() -> Vec<ToolSpec> {
+    vec![
+        ToolSpec {
+            name: "bash",
+            description: "Execute a shell command in the current workspace.",
+            input_schema: json!({
+                "type": "object",
+                "properties": {
+                    "command": { "type": "string" },
+                    "timeout": { "type": "integer", "minimum": 1 },
+                    "description": { "type": "string" },
+                    "run_in_background": { "type": "boolean" },
+                    "dangerouslyDisableSandbox": { "type": "boolean" }
+                },
+                "required": ["command"],
+                "additionalProperties": false
+            }),
+        },
+        ToolSpec {
+            name: "read_file",
+            description: "Read a text file from the workspace.",
+            input_schema: json!({
+                "type": "object",
+                "properties": {
+                    "path": { "type": "string" },
+                    "offset": { "type": "integer", "minimum": 0 },
+                    "limit": { "type": "integer", "minimum": 1 }
+                },
+                "required": ["path"],
+                "additionalProperties": false
+            }),
+        },
+        ToolSpec {
+            name: "write_file",
+            description: "Write a text file in the workspace.",
+            input_schema: json!({
+                "type": "object",
+                "properties": {
+                    "path": { "type": "string" },
+                    "content": { "type": "string" }
+                },
+                "required": ["path", "content"],
+                "additionalProperties": false
+            }),
+        },
+        ToolSpec {
+            name: "edit_file",
+            description: "Replace text in a workspace file.",
+            input_schema: json!({
+                "type": "object",
+                "properties": {
+                    "path": { "type": "string" },
+                    "old_string": { "type": "string" },
+                    "new_string": { "type": "string" },
+                    "replace_all": { "type": "boolean" }
+                },
+                "required": ["path", "old_string", "new_string"],
+                "additionalProperties": false
+            }),
+        },
+        ToolSpec {
+            name: "glob_search",
+            description: "Find files by glob pattern.",
+            input_schema: json!({
+                "type": "object",
+                "properties": {
+                    "pattern": { "type": "string" },
+                    "path": { "type": "string" }
+                },
+                "required": ["pattern"],
+                "additionalProperties": false
+            }),
+        },
+        ToolSpec {
+            name: "grep_search",
+            description: "Search file contents with a regex pattern.",
+            input_schema: json!({
+                "type": "object",
+                "properties": {
+                    "pattern": { "type": "string" },
+                    "path": { "type": "string" },
+                    "glob": { "type": "string" },
+                    "output_mode": { "type": "string" },
+                    "-B": { "type": "integer", "minimum": 0 },
+                    "-A": { "type": "integer", "minimum": 0 },
+                    "-C": { "type": "integer", "minimum": 0 },
+                    "context": { "type": "integer", "minimum": 0 },
+                    "-n": { "type": "boolean" },
+                    "-i": { "type": "boolean" },
+                    "type": { "type": "string" },
+                    "head_limit": { "type": "integer", "minimum": 1 },
+                    "offset": { "type": "integer", "minimum": 0 },
+                    "multiline": { "type": "boolean" }
+                },
+                "required": ["pattern"],
+                "additionalProperties": false
+            }),
+        },
+    ]
+}
+
+pub fn execute_tool(name: &str, input: &Value) -> Result<String, String> {
+    match name {
+        "bash" => from_value::<BashCommandInput>(input).and_then(run_bash),
+        "read_file" => from_value::<ReadFileInput>(input).and_then(run_read_file),
+        "write_file" => from_value::<WriteFileInput>(input).and_then(run_write_file),
+        "edit_file" => from_value::<EditFileInput>(input).and_then(run_edit_file),
+        "glob_search" => from_value::<GlobSearchInputValue>(input).and_then(run_glob_search),
+        "grep_search" => from_value::<GrepSearchInput>(input).and_then(run_grep_search),
+        _ => Err(format!("unsupported tool: {name}")),
+    }
+}
+
+fn from_value<T: for<'de> Deserialize<'de>>(input: &Value) -> Result<T, String> {
+    serde_json::from_value(input.clone()).map_err(|error| error.to_string())
+}
+
+fn run_bash(input: BashCommandInput) -> Result<String, String> {
+    serde_json::to_string_pretty(&execute_bash(input).map_err(|error| error.to_string())?)
+        .map_err(|error| error.to_string())
+}
+
+fn run_read_file(input: ReadFileInput) -> Result<String, String> {
+    to_pretty_json(read_file(&input.path, input.offset, input.limit).map_err(io_to_string)?)
+}
+
+fn run_write_file(input: WriteFileInput) -> Result<String, String> {
+    to_pretty_json(write_file(&input.path, &input.content).map_err(io_to_string)?)
+}
+
+fn run_edit_file(input: EditFileInput) -> Result<String, String> {
+    to_pretty_json(
+        edit_file(
+            &input.path,
+            &input.old_string,
+            &input.new_string,
+            input.replace_all.unwrap_or(false),
+        )
+        .map_err(io_to_string)?,
+    )
+}
+
+fn run_glob_search(input: GlobSearchInputValue) -> Result<String, String> {
+    to_pretty_json(glob_search(&input.pattern, input.path.as_deref()).map_err(io_to_string)?)
+}
+
+fn run_grep_search(input: GrepSearchInput) -> Result<String, String> {
+    to_pretty_json(grep_search(&input).map_err(io_to_string)?)
+}
+
+fn to_pretty_json<T: serde::Serialize>(value: T) -> Result<String, String> {
+    serde_json::to_string_pretty(&value).map_err(|error| error.to_string())
+}
+
+fn io_to_string(error: std::io::Error) -> String {
+    error.to_string()
+}
+
+#[derive(Debug, Deserialize)]
+struct ReadFileInput {
+    path: String,
+    offset: Option<usize>,
+    limit: Option<usize>,
+}
+
+#[derive(Debug, Deserialize)]
+struct WriteFileInput {
+    path: String,
+    content: String,
+}
+
+#[derive(Debug, Deserialize)]
+struct EditFileInput {
+    path: String,
+    old_string: String,
+    new_string: String,
+    replace_all: Option<bool>,
+}
+
+#[derive(Debug, Deserialize)]
+struct GlobSearchInputValue {
+    pattern: String,
+    path: Option<String>,
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{execute_tool, mvp_tool_specs};
+    use serde_json::json;
+
+    #[test]
+    fn exposes_mvp_tools() {
+        let names = mvp_tool_specs()
+            .into_iter()
+            .map(|spec| spec.name)
+            .collect::<Vec<_>>();
+        assert!(names.contains(&"bash"));
+        assert!(names.contains(&"read_file"));
+    }
+
+    #[test]
+    fn rejects_unknown_tool_names() {
+        let error = execute_tool("nope", &json!({})).expect_err("tool should be rejected");
+        assert!(error.contains("unsupported tool"));
+    }
+}