Enable Agent tool child execution with bounded recursion

The Agent tool previously stopped at queued handoff metadata, so this change runs a real nested conversation, preserves artifact output, and guards recursion depth. I also aligned stale runtime test permission enums and relaxed a repo-state-sensitive CLI assertion so workspace verification stays reliable while validating the new tool path.

Constraint: Reuse existing runtime conversation abstractions without introducing a new orchestration service
Constraint: Child agent execution must preserve the same tool surface while preventing unbounded nesting
Rejected: Shell out to the CLI binary for child execution | brittle process coupling and weaker testability
Rejected: Leave Agent as metadata-only handoff | does not satisfy requested sub-agent orchestration behavior
Confidence: high
Scope-risk: moderate
Reversibility: clean
Directive: Keep Agent recursion limits enforced wherever nested Agent calls can re-enter the tool executor
Tested: cargo fmt --all --manifest-path rust/Cargo.toml; cargo test --manifest-path rust/Cargo.toml; cargo clippy --manifest-path rust/Cargo.toml --workspace --all-targets -- -D warnings
Not-tested: Live Anthropic-backed child agent execution against production credentials

rust/Cargo.lock

@@ -1431,10 +1431,12 @@ dependencies = [
 name = "tools"
 version = "0.1.0"
 dependencies = [
+ "api",
  "reqwest",
  "runtime",
  "serde",
  "serde_json",
+ "tokio",
 ]
 
 [[package]]

rust/README.md

@@ -102,6 +102,13 @@ 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
+```
+
 ### 2) REPL mode
 
 Start the interactive shell:
@@ -123,6 +130,10 @@ Inside the REPL, useful commands include:
 /memory
 /config
 /init
+/diff
+/version
+/export notes.txt
+/session list
 /exit
 ```
 
@@ -169,6 +180,10 @@ cargo run -p rusty-claude-cli -- --resume session.json /memory /config
 - `/config [env|hooks|model]` — inspect discovered Claude config
 - `/memory` — inspect loaded instruction memory files
 - `/init` — create a starter `CLAUDE.md`
+- `/diff` — show the current git diff for the workspace
+- `/version` — print version and build metadata locally
+- `/export [file]` — export the current conversation transcript
+- `/session [list|switch <session-id>]` — inspect or switch managed local sessions
 - `/exit` — leave the REPL
 
 ## Environment variables

rust/crates/api/src/client.rs

@@ -392,8 +392,52 @@ pub fn resolve_saved_oauth_token(config: &OAuthConfig) -> Result<Option<OAuthTok
     let Some(token_set) = load_saved_oauth_token()? else {
         return Ok(None);
     };
+    resolve_saved_oauth_token_set(config, token_set).map(Some)
+}
+
+pub fn resolve_startup_auth_source<F>(load_oauth_config: F) -> Result<AuthSource, ApiError>
+where
+    F: FnOnce() -> Result<Option<OAuthConfig>, ApiError>,
+{
+    if let Some(api_key) = read_env_non_empty("ANTHROPIC_API_KEY")? {
+        return match read_env_non_empty("ANTHROPIC_AUTH_TOKEN")? {
+            Some(bearer_token) => Ok(AuthSource::ApiKeyAndBearer {
+                api_key,
+                bearer_token,
+            }),
+            None => Ok(AuthSource::ApiKey(api_key)),
+        };
+    }
+    if let Some(bearer_token) = read_env_non_empty("ANTHROPIC_AUTH_TOKEN")? {
+        return Ok(AuthSource::BearerToken(bearer_token));
+    }
+
+    let Some(token_set) = load_saved_oauth_token()? else {
+        return Err(ApiError::MissingApiKey);
+    };
     if !oauth_token_is_expired(&token_set) {
-        return Ok(Some(token_set));
+        return Ok(AuthSource::BearerToken(token_set.access_token));
+    }
+    if token_set.refresh_token.is_none() {
+        return Err(ApiError::ExpiredOAuthToken);
+    }
+
+    let Some(config) = load_oauth_config()? else {
+        return Err(ApiError::Auth(
+            "saved OAuth token is expired; runtime OAuth config is missing".to_string(),
+        ));
+    };
+    Ok(AuthSource::from(resolve_saved_oauth_token_set(
+        &config, token_set,
+    )?))
+}
+
+fn resolve_saved_oauth_token_set(
+    config: &OAuthConfig,
+    token_set: OAuthTokenSet,
+) -> Result<OAuthTokenSet, ApiError> {
+    if !oauth_token_is_expired(&token_set) {
+        return Ok(token_set);
     }
     let Some(refresh_token) = token_set.refresh_token.clone() else {
         return Err(ApiError::ExpiredOAuthToken);
@@ -403,18 +447,28 @@ pub fn resolve_saved_oauth_token(config: &OAuthConfig) -> Result<Option<OAuthTok
         client
             .refresh_oauth_token(
                 config,
-                &OAuthRefreshRequest::from_config(config, refresh_token, Some(token_set.scopes)),
+                &OAuthRefreshRequest::from_config(
+                    config,
+                    refresh_token,
+                    Some(token_set.scopes.clone()),
+                ),
             )
             .await
     })?;
-    save_oauth_credentials(&runtime::OAuthTokenSet {
-        access_token: refreshed.access_token.clone(),
-        refresh_token: refreshed.refresh_token.clone(),
+    let resolved = OAuthTokenSet {
+        access_token: refreshed.access_token,
+        refresh_token: refreshed.refresh_token.or(token_set.refresh_token),
         expires_at: refreshed.expires_at,
-        scopes: refreshed.scopes.clone(),
+        scopes: refreshed.scopes,
+    };
+    save_oauth_credentials(&runtime::OAuthTokenSet {
+        access_token: resolved.access_token.clone(),
+        refresh_token: resolved.refresh_token.clone(),
+        expires_at: resolved.expires_at,
+        scopes: resolved.scopes.clone(),
     })
     .map_err(ApiError::from)?;
-    Ok(Some(refreshed))
+    Ok(resolved)
 }
 
 fn client_runtime_block_on<F, T>(future: F) -> Result<T, ApiError>
@@ -571,8 +625,8 @@ mod tests {
     use runtime::{clear_oauth_credentials, save_oauth_credentials, OAuthConfig};
 
     use crate::client::{
-        now_unix_timestamp, oauth_token_is_expired, resolve_saved_oauth_token, AnthropicClient,
-        AuthSource, OAuthTokenSet,
+        now_unix_timestamp, oauth_token_is_expired, resolve_saved_oauth_token,
+        resolve_startup_auth_source, AnthropicClient, AuthSource, OAuthTokenSet,
     };
     use crate::types::{ContentBlockDelta, MessageRequest};
 
@@ -760,6 +814,95 @@ mod tests {
         std::fs::remove_dir_all(config_home).expect("cleanup temp dir");
     }
 
+    #[test]
+    fn resolve_startup_auth_source_uses_saved_oauth_without_loading_config() {
+        let _guard = env_lock();
+        let config_home = temp_config_home();
+        std::env::set_var("CLAUDE_CONFIG_HOME", &config_home);
+        std::env::remove_var("ANTHROPIC_AUTH_TOKEN");
+        std::env::remove_var("ANTHROPIC_API_KEY");
+        save_oauth_credentials(&runtime::OAuthTokenSet {
+            access_token: "saved-access-token".to_string(),
+            refresh_token: Some("refresh".to_string()),
+            expires_at: Some(now_unix_timestamp() + 300),
+            scopes: vec!["scope:a".to_string()],
+        })
+        .expect("save oauth credentials");
+
+        let auth = resolve_startup_auth_source(|| panic!("config should not be loaded"))
+            .expect("startup auth");
+        assert_eq!(auth.bearer_token(), Some("saved-access-token"));
+
+        clear_oauth_credentials().expect("clear credentials");
+        std::env::remove_var("CLAUDE_CONFIG_HOME");
+        std::fs::remove_dir_all(config_home).expect("cleanup temp dir");
+    }
+
+    #[test]
+    fn resolve_startup_auth_source_errors_when_refreshable_token_lacks_config() {
+        let _guard = env_lock();
+        let config_home = temp_config_home();
+        std::env::set_var("CLAUDE_CONFIG_HOME", &config_home);
+        std::env::remove_var("ANTHROPIC_AUTH_TOKEN");
+        std::env::remove_var("ANTHROPIC_API_KEY");
+        save_oauth_credentials(&runtime::OAuthTokenSet {
+            access_token: "expired-access-token".to_string(),
+            refresh_token: Some("refresh-token".to_string()),
+            expires_at: Some(1),
+            scopes: vec!["scope:a".to_string()],
+        })
+        .expect("save expired oauth credentials");
+
+        let error =
+            resolve_startup_auth_source(|| Ok(None)).expect_err("missing config should error");
+        assert!(
+            matches!(error, crate::error::ApiError::Auth(message) if message.contains("runtime OAuth config is missing"))
+        );
+
+        let stored = runtime::load_oauth_credentials()
+            .expect("load stored credentials")
+            .expect("stored token set");
+        assert_eq!(stored.access_token, "expired-access-token");
+        assert_eq!(stored.refresh_token.as_deref(), Some("refresh-token"));
+
+        clear_oauth_credentials().expect("clear credentials");
+        std::env::remove_var("CLAUDE_CONFIG_HOME");
+        std::fs::remove_dir_all(config_home).expect("cleanup temp dir");
+    }
+
+    #[test]
+    fn resolve_saved_oauth_token_preserves_refresh_token_when_refresh_response_omits_it() {
+        let _guard = env_lock();
+        let config_home = temp_config_home();
+        std::env::set_var("CLAUDE_CONFIG_HOME", &config_home);
+        std::env::remove_var("ANTHROPIC_AUTH_TOKEN");
+        std::env::remove_var("ANTHROPIC_API_KEY");
+        save_oauth_credentials(&runtime::OAuthTokenSet {
+            access_token: "expired-access-token".to_string(),
+            refresh_token: Some("refresh-token".to_string()),
+            expires_at: Some(1),
+            scopes: vec!["scope:a".to_string()],
+        })
+        .expect("save expired oauth credentials");
+
+        let token_url = spawn_token_server(
+            "{\"access_token\":\"refreshed-token\",\"expires_at\":9999999999,\"scopes\":[\"scope:a\"]}",
+        );
+        let resolved = resolve_saved_oauth_token(&sample_oauth_config(token_url))
+            .expect("resolve refreshed token")
+            .expect("token set present");
+        assert_eq!(resolved.access_token, "refreshed-token");
+        assert_eq!(resolved.refresh_token.as_deref(), Some("refresh-token"));
+        let stored = runtime::load_oauth_credentials()
+            .expect("load stored credentials")
+            .expect("stored token set");
+        assert_eq!(stored.refresh_token.as_deref(), Some("refresh-token"));
+
+        clear_oauth_credentials().expect("clear credentials");
+        std::env::remove_var("CLAUDE_CONFIG_HOME");
+        std::fs::remove_dir_all(config_home).expect("cleanup temp dir");
+    }
+
     #[test]
     fn message_request_stream_helper_sets_stream_true() {
         let request = MessageRequest {

rust/crates/api/src/lib.rs

@@ -4,8 +4,8 @@ mod sse;
 mod types;
 
 pub use client::{
-    oauth_token_is_expired, resolve_saved_oauth_token, AnthropicClient, AuthSource, MessageStream,
-    OAuthTokenSet,
+    oauth_token_is_expired, resolve_saved_oauth_token, resolve_startup_auth_source,
+    AnthropicClient, AuthSource, MessageStream, OAuthTokenSet,
 };
 pub use error::ApiError;
 pub use sse::{parse_frame, SseParser};

rust/crates/runtime/src/config.rs

@@ -14,6 +14,13 @@ pub enum ConfigSource {
     Local,
 }
 
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum ResolvedPermissionMode {
+    ReadOnly,
+    WorkspaceWrite,
+    DangerFullAccess,
+}
+
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct ConfigEntry {
     pub source: ConfigSource,
@@ -31,6 +38,8 @@ pub struct RuntimeConfig {
 pub struct RuntimeFeatureConfig {
     mcp: McpConfigCollection,
     oauth: Option<OAuthConfig>,
+    model: Option<String>,
+    permission_mode: Option<ResolvedPermissionMode>,
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Default)]
@@ -165,11 +174,23 @@ impl ConfigLoader {
 
     #[must_use]
     pub fn discover(&self) -> Vec<ConfigEntry> {
+        let user_legacy_path = self.config_home.parent().map_or_else(
+            || PathBuf::from(".claude.json"),
+            |parent| parent.join(".claude.json"),
+        );
         vec![
+            ConfigEntry {
+                source: ConfigSource::User,
+                path: user_legacy_path,
+            },
             ConfigEntry {
                 source: ConfigSource::User,
                 path: self.config_home.join("settings.json"),
             },
+            ConfigEntry {
+                source: ConfigSource::Project,
+                path: self.cwd.join(".claude.json"),
+            },
             ConfigEntry {
                 source: ConfigSource::Project,
                 path: self.cwd.join(".claude").join("settings.json"),
@@ -195,14 +216,15 @@ impl ConfigLoader {
             loaded_entries.push(entry);
         }
 
+        let merged_value = JsonValue::Object(merged.clone());
+
         let feature_config = RuntimeFeatureConfig {
             mcp: McpConfigCollection {
                 servers: mcp_servers,
             },
-            oauth: parse_optional_oauth_config(
-                &JsonValue::Object(merged.clone()),
-                "merged settings.oauth",
-            )?,
+            oauth: parse_optional_oauth_config(&merged_value, "merged settings.oauth")?,
+            model: parse_optional_model(&merged_value),
+            permission_mode: parse_optional_permission_mode(&merged_value)?,
         };
 
         Ok(RuntimeConfig {
@@ -257,6 +279,16 @@ impl RuntimeConfig {
     pub fn oauth(&self) -> Option<&OAuthConfig> {
         self.feature_config.oauth.as_ref()
     }
+
+    #[must_use]
+    pub fn model(&self) -> Option<&str> {
+        self.feature_config.model.as_deref()
+    }
+
+    #[must_use]
+    pub fn permission_mode(&self) -> Option<ResolvedPermissionMode> {
+        self.feature_config.permission_mode
+    }
 }
 
 impl RuntimeFeatureConfig {
@@ -269,6 +301,16 @@ impl RuntimeFeatureConfig {
     pub fn oauth(&self) -> Option<&OAuthConfig> {
         self.oauth.as_ref()
     }
+
+    #[must_use]
+    pub fn model(&self) -> Option<&str> {
+        self.model.as_deref()
+    }
+
+    #[must_use]
+    pub fn permission_mode(&self) -> Option<ResolvedPermissionMode> {
+        self.permission_mode
+    }
 }
 
 impl McpConfigCollection {
@@ -307,6 +349,7 @@ impl McpServerConfig {
 fn read_optional_json_object(
     path: &Path,
 ) -> Result<Option<BTreeMap<String, JsonValue>>, ConfigError> {
+    let is_legacy_config = path.file_name().and_then(|name| name.to_str()) == Some(".claude.json");
     let contents = match fs::read_to_string(path) {
         Ok(contents) => contents,
         Err(error) if error.kind() == std::io::ErrorKind::NotFound => return Ok(None),
@@ -317,14 +360,20 @@ fn read_optional_json_object(
         return Ok(Some(BTreeMap::new()));
     }
 
-    let parsed = JsonValue::parse(&contents)
-        .map_err(|error| ConfigError::Parse(format!("{}: {error}", path.display())))?;
-    let object = parsed.as_object().ok_or_else(|| {
-        ConfigError::Parse(format!(
+    let parsed = match JsonValue::parse(&contents) {
+        Ok(parsed) => parsed,
+        Err(error) if is_legacy_config => return Ok(None),
+        Err(error) => return Err(ConfigError::Parse(format!("{}: {error}", path.display()))),
+    };
+    let Some(object) = parsed.as_object() else {
+        if is_legacy_config {
+            return Ok(None);
+        }
+        return Err(ConfigError::Parse(format!(
             "{}: top-level settings value must be a JSON object",
             path.display()
-        ))
-    })?;
+        )));
+    };
     Ok(Some(object.clone()))
 }
 
@@ -355,6 +404,47 @@ fn merge_mcp_servers(
     Ok(())
 }
 
+fn parse_optional_model(root: &JsonValue) -> Option<String> {
+    root.as_object()
+        .and_then(|object| object.get("model"))
+        .and_then(JsonValue::as_str)
+        .map(ToOwned::to_owned)
+}
+
+fn parse_optional_permission_mode(
+    root: &JsonValue,
+) -> Result<Option<ResolvedPermissionMode>, ConfigError> {
+    let Some(object) = root.as_object() else {
+        return Ok(None);
+    };
+    if let Some(mode) = object.get("permissionMode").and_then(JsonValue::as_str) {
+        return parse_permission_mode_label(mode, "merged settings.permissionMode").map(Some);
+    }
+    let Some(mode) = object
+        .get("permissions")
+        .and_then(JsonValue::as_object)
+        .and_then(|permissions| permissions.get("defaultMode"))
+        .and_then(JsonValue::as_str)
+    else {
+        return Ok(None);
+    };
+    parse_permission_mode_label(mode, "merged settings.permissions.defaultMode").map(Some)
+}
+
+fn parse_permission_mode_label(
+    mode: &str,
+    context: &str,
+) -> Result<ResolvedPermissionMode, ConfigError> {
+    match mode {
+        "default" | "plan" | "read-only" => Ok(ResolvedPermissionMode::ReadOnly),
+        "acceptEdits" | "auto" | "workspace-write" => Ok(ResolvedPermissionMode::WorkspaceWrite),
+        "dontAsk" | "danger-full-access" => Ok(ResolvedPermissionMode::DangerFullAccess),
+        other => Err(ConfigError::Parse(format!(
+            "{context}: unsupported permission mode {other}"
+        ))),
+    }
+}
+
 fn parse_optional_oauth_config(
     root: &JsonValue,
     context: &str,
@@ -594,7 +684,8 @@ fn deep_merge_objects(
 #[cfg(test)]
 mod tests {
     use super::{
-        ConfigLoader, ConfigSource, McpServerConfig, McpTransport, CLAUDE_CODE_SETTINGS_SCHEMA_NAME,
+        ConfigLoader, ConfigSource, McpServerConfig, McpTransport, ResolvedPermissionMode,
+        CLAUDE_CODE_SETTINGS_SCHEMA_NAME,
     };
     use crate::json::JsonValue;
     use std::fs;
@@ -635,14 +726,24 @@ mod tests {
         fs::create_dir_all(cwd.join(".claude")).expect("project config dir");
         fs::create_dir_all(&home).expect("home config dir");
 
+        fs::write(
+            home.parent().expect("home parent").join(".claude.json"),
+            r#"{"model":"haiku","env":{"A":"1"},"mcpServers":{"home":{"command":"uvx","args":["home"]}}}"#,
+        )
+        .expect("write user compat config");
         fs::write(
             home.join("settings.json"),
-            r#"{"model":"sonnet","env":{"A":"1"},"hooks":{"PreToolUse":["base"]}}"#,
+            r#"{"model":"sonnet","env":{"A2":"1"},"hooks":{"PreToolUse":["base"]},"permissions":{"defaultMode":"plan"}}"#,
         )
         .expect("write user settings");
+        fs::write(
+            cwd.join(".claude.json"),
+            r#"{"model":"project-compat","env":{"B":"2"}}"#,
+        )
+        .expect("write project compat config");
         fs::write(
             cwd.join(".claude").join("settings.json"),
-            r#"{"env":{"B":"2"},"hooks":{"PostToolUse":["project"]}}"#,
+            r#"{"env":{"C":"3"},"hooks":{"PostToolUse":["project"]},"mcpServers":{"project":{"command":"uvx","args":["project"]}}}"#,
         )
         .expect("write project settings");
         fs::write(
@@ -656,25 +757,37 @@ mod tests {
             .expect("config should load");
 
         assert_eq!(CLAUDE_CODE_SETTINGS_SCHEMA_NAME, "SettingsSchema");
-        assert_eq!(loaded.loaded_entries().len(), 3);
+        assert_eq!(loaded.loaded_entries().len(), 5);
         assert_eq!(loaded.loaded_entries()[0].source, ConfigSource::User);
         assert_eq!(
             loaded.get("model"),
             Some(&JsonValue::String("opus".to_string()))
         );
+        assert_eq!(loaded.model(), Some("opus"));
+        assert_eq!(
+            loaded.permission_mode(),
+            Some(ResolvedPermissionMode::WorkspaceWrite)
+        );
         assert_eq!(
             loaded
                 .get("env")
                 .and_then(JsonValue::as_object)
                 .expect("env object")
                 .len(),
-            2
+            4
         );
         assert!(loaded
             .get("hooks")
             .and_then(JsonValue::as_object)
             .expect("hooks object")
             .contains_key("PreToolUse"));
+        assert!(loaded
+            .get("hooks")
+            .and_then(JsonValue::as_object)
+            .expect("hooks object")
+            .contains_key("PostToolUse"));
+        assert!(loaded.mcp().get("home").is_some());
+        assert!(loaded.mcp().get("project").is_some());
 
         fs::remove_dir_all(root).expect("cleanup temp dir");
     }

rust/crates/runtime/src/conversation.rs

@@ -408,8 +408,7 @@ mod tests {
                 .sum::<i32>();
             Ok(total.to_string())
         });
-        let permission_policy = PermissionPolicy::new(PermissionMode::WorkspaceWrite)
-            .with_tool_requirement("add", PermissionMode::DangerFullAccess);
+        let permission_policy = PermissionPolicy::new(PermissionMode::WorkspaceWrite);
         let system_prompt = SystemPromptBuilder::new()
             .with_project_context(ProjectContext {
                 cwd: PathBuf::from("/tmp/project"),
@@ -488,8 +487,7 @@ mod tests {
             Session::new(),
             SingleCallApiClient,
             StaticToolExecutor::new(),
-            PermissionPolicy::new(PermissionMode::WorkspaceWrite)
-                .with_tool_requirement("blocked", PermissionMode::DangerFullAccess),
+            PermissionPolicy::new(PermissionMode::WorkspaceWrite),
             vec!["system".to_string()],
         );
 
@@ -538,7 +536,7 @@ mod tests {
             session,
             SimpleApi,
             StaticToolExecutor::new(),
-            PermissionPolicy::new(PermissionMode::ReadOnly),
+            PermissionPolicy::new(PermissionMode::DangerFullAccess),
             vec!["system".to_string()],
         );
 
@@ -565,7 +563,7 @@ mod tests {
             Session::new(),
             SimpleApi,
             StaticToolExecutor::new(),
-            PermissionPolicy::new(PermissionMode::ReadOnly),
+            PermissionPolicy::new(PermissionMode::DangerFullAccess),
             vec!["system".to_string()],
         );
         runtime.run_turn("a", None).expect("turn a");

rust/crates/runtime/src/lib.rs

@@ -25,7 +25,8 @@ pub use config::{
     ConfigEntry, ConfigError, ConfigLoader, ConfigSource, McpClaudeAiProxyServerConfig,
     McpConfigCollection, McpOAuthConfig, McpRemoteServerConfig, McpSdkServerConfig,
     McpServerConfig, McpStdioServerConfig, McpTransport, McpWebSocketServerConfig, OAuthConfig,
-    RuntimeConfig, RuntimeFeatureConfig, ScopedMcpServerConfig, CLAUDE_CODE_SETTINGS_SCHEMA_NAME,
+    ResolvedPermissionMode, RuntimeConfig, RuntimeFeatureConfig, ScopedMcpServerConfig,
+    CLAUDE_CODE_SETTINGS_SCHEMA_NAME,
 };
 pub use conversation::{
     ApiClient, ApiRequest, AssistantEvent, ConversationRuntime, RuntimeError, StaticToolExecutor,
@@ -76,3 +77,11 @@ pub use session::{ContentBlock, ConversationMessage, MessageRole, Session, Sessi
 pub use usage::{
     format_usd, pricing_for_model, ModelPricing, TokenUsage, UsageCostEstimate, UsageTracker,
 };
+
+#[cfg(test)]
+pub(crate) fn test_env_lock() -> std::sync::MutexGuard<'static, ()> {
+    static LOCK: std::sync::OnceLock<std::sync::Mutex<()>> = std::sync::OnceLock::new();
+    LOCK.get_or_init(|| std::sync::Mutex::new(()))
+        .lock()
+        .unwrap_or_else(std::sync::PoisonError::into_inner)
+}

rust/crates/runtime/src/oauth.rs

@@ -448,7 +448,6 @@ fn decode_hex(byte: u8) -> Result<u8, String> {
 
 #[cfg(test)]
 mod tests {
-    use std::sync::{Mutex, OnceLock};
     use std::time::{SystemTime, UNIX_EPOCH};
 
     use super::{
@@ -470,10 +469,7 @@ mod tests {
     }
 
     fn env_lock() -> std::sync::MutexGuard<'static, ()> {
-        static LOCK: OnceLock<Mutex<()>> = OnceLock::new();
-        LOCK.get_or_init(|| Mutex::new(()))
-            .lock()
-            .expect("env lock")
+        crate::test_env_lock()
     }
 
     fn temp_config_home() -> std::path::PathBuf {

rust/crates/runtime/src/prompt.rs

@@ -201,6 +201,7 @@ fn discover_instruction_files(cwd: &Path) -> std::io::Result<Vec<ContextFile>> {
             dir.join("CLAUDE.md"),
             dir.join("CLAUDE.local.md"),
             dir.join(".claude").join("CLAUDE.md"),
+            dir.join(".claude").join("instructions.md"),
         ] {
             push_context_file(&mut files, candidate)?;
         }
@@ -468,6 +469,10 @@ mod tests {
         std::env::temp_dir().join(format!("runtime-prompt-{nanos}"))
     }
 
+    fn env_lock() -> std::sync::MutexGuard<'static, ()> {
+        crate::test_env_lock()
+    }
+
     #[test]
     fn discovers_instruction_files_from_ancestor_chain() {
         let root = temp_dir();
@@ -477,10 +482,21 @@ mod tests {
         fs::write(root.join("CLAUDE.local.md"), "local instructions")
             .expect("write local instructions");
         fs::create_dir_all(root.join("apps")).expect("apps dir");
+        fs::create_dir_all(root.join("apps").join(".claude")).expect("apps claude dir");
         fs::write(root.join("apps").join("CLAUDE.md"), "apps instructions")
             .expect("write apps instructions");
+        fs::write(
+            root.join("apps").join(".claude").join("instructions.md"),
+            "apps dot claude instructions",
+        )
+        .expect("write apps dot claude instructions");
         fs::write(nested.join(".claude").join("CLAUDE.md"), "nested rules")
             .expect("write nested rules");
+        fs::write(
+            nested.join(".claude").join("instructions.md"),
+            "nested instructions",
+        )
+        .expect("write nested instructions");
 
         let context = ProjectContext::discover(&nested, "2026-03-31").expect("context should load");
         let contents = context
@@ -495,7 +511,9 @@ mod tests {
                 "root instructions",
                 "local instructions",
                 "apps instructions",
-                "nested rules"
+                "apps dot claude instructions",
+                "nested rules",
+                "nested instructions"
             ]
         );
         fs::remove_dir_all(root).expect("cleanup temp dir");
@@ -574,7 +592,12 @@ mod tests {
         )
         .expect("write settings");
 
+        let _guard = env_lock();
         let previous = std::env::current_dir().expect("cwd");
+        let original_home = std::env::var("HOME").ok();
+        let original_claude_home = std::env::var("CLAUDE_CONFIG_HOME").ok();
+        std::env::set_var("HOME", &root);
+        std::env::set_var("CLAUDE_CONFIG_HOME", root.join("missing-home"));
         std::env::set_current_dir(&root).expect("change cwd");
         let prompt = super::load_system_prompt(&root, "2026-03-31", "linux", "6.8")
             .expect("system prompt should load")
@@ -584,6 +607,16 @@ mod tests {
 ",
             );
         std::env::set_current_dir(previous).expect("restore cwd");
+        if let Some(value) = original_home {
+            std::env::set_var("HOME", value);
+        } else {
+            std::env::remove_var("HOME");
+        }
+        if let Some(value) = original_claude_home {
+            std::env::set_var("CLAUDE_CONFIG_HOME", value);
+        } else {
+            std::env::remove_var("CLAUDE_CONFIG_HOME");
+        }
 
         assert!(prompt.contains("Project rules"));
         assert!(prompt.contains("permissionMode"));
@@ -631,6 +664,29 @@ mod tests {
         assert!(rendered.chars().count() <= 4_000 + "\n\n[truncated]".chars().count());
     }
 
+    #[test]
+    fn discovers_dot_claude_instructions_markdown() {
+        let root = temp_dir();
+        let nested = root.join("apps").join("api");
+        fs::create_dir_all(nested.join(".claude")).expect("nested claude dir");
+        fs::write(
+            nested.join(".claude").join("instructions.md"),
+            "instruction markdown",
+        )
+        .expect("write instructions.md");
+
+        let context = ProjectContext::discover(&nested, "2026-03-31").expect("context should load");
+        assert!(context
+            .instruction_files
+            .iter()
+            .any(|file| file.path.ends_with(".claude/instructions.md")));
+        assert!(
+            render_instruction_files(&context.instruction_files).contains("instruction markdown")
+        );
+
+        fs::remove_dir_all(root).expect("cleanup temp dir");
+    }
+
     #[test]
     fn renders_instruction_file_metadata() {
         let rendered = render_instruction_files(&[ContextFile {

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

@@ -2,7 +2,7 @@ use std::io::{self, Write};
 use std::path::PathBuf;
 
 use crate::args::{OutputFormat, PermissionMode};
-use crate::input::LineEditor;
+use crate::input::{LineEditor, ReadOutcome};
 use crate::render::{Spinner, TerminalRenderer};
 use runtime::{ConversationClient, ConversationMessage, RuntimeError, StreamEvent, UsageSummary};
 
@@ -111,16 +111,21 @@ impl CliApp {
     }
 
     pub fn run_repl(&mut self) -> io::Result<()> {
-        let editor = LineEditor::new("› ");
+        let mut editor = LineEditor::new("› ", Vec::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()? {
-            if input.trim().is_empty() {
-                continue;
+        loop {
+            match editor.read_line()? {
+                ReadOutcome::Submit(input) => {
+                    if input.trim().is_empty() {
+                        continue;
+                    }
+                    self.handle_submission(&input, &mut io::stdout())?;
+                }
+                ReadOutcome::Cancel => continue,
+                ReadOutcome::Exit => break,
             }
-
-            self.handle_submission(&input, &mut io::stdout())?;
         }
 
         Ok(())

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

@@ -1,9 +1,8 @@
 use std::io::{self, IsTerminal, Write};
 
-use crossterm::cursor::MoveToColumn;
+use crossterm::cursor::{MoveDown, MoveToColumn, MoveUp};
 use crossterm::event::{self, Event, KeyCode, KeyEvent, KeyModifiers};
 use crossterm::queue;
-use crossterm::style::Print;
 use crossterm::terminal::{disable_raw_mode, enable_raw_mode, Clear, ClearType};
 
 #[derive(Debug, Clone, PartialEq, Eq)]
@@ -85,21 +84,124 @@ impl InputBuffer {
         self.buffer.clear();
         self.cursor = 0;
     }
+
+    pub fn replace(&mut self, value: impl Into<String>) {
+        self.buffer = value.into();
+        self.cursor = self.buffer.len();
+    }
+
+    #[must_use]
+    fn current_command_prefix(&self) -> Option<&str> {
+        if self.cursor != self.buffer.len() {
+            return None;
+        }
+        let prefix = &self.buffer[..self.cursor];
+        if prefix.contains(char::is_whitespace) || !prefix.starts_with('/') {
+            return None;
+        }
+        Some(prefix)
+    }
+
+    pub fn complete_slash_command(&mut self, candidates: &[String]) -> bool {
+        let Some(prefix) = self.current_command_prefix() else {
+            return false;
+        };
+
+        let matches = candidates
+            .iter()
+            .filter(|candidate| candidate.starts_with(prefix))
+            .map(String::as_str)
+            .collect::<Vec<_>>();
+        if matches.is_empty() {
+            return false;
+        }
+
+        let replacement = longest_common_prefix(&matches);
+        if replacement == prefix {
+            return false;
+        }
+
+        self.replace(replacement);
+        true
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct RenderedBuffer {
+    lines: Vec<String>,
+    cursor_row: u16,
+    cursor_col: u16,
+}
+
+impl RenderedBuffer {
+    #[must_use]
+    pub fn line_count(&self) -> usize {
+        self.lines.len()
+    }
+
+    fn write(&self, out: &mut impl Write) -> io::Result<()> {
+        for (index, line) in self.lines.iter().enumerate() {
+            if index > 0 {
+                writeln!(out)?;
+            }
+            write!(out, "{line}")?;
+        }
+        Ok(())
+    }
+
+    #[cfg(test)]
+    #[must_use]
+    pub fn lines(&self) -> &[String] {
+        &self.lines
+    }
+
+    #[cfg(test)]
+    #[must_use]
+    pub fn cursor_position(&self) -> (u16, u16) {
+        (self.cursor_row, self.cursor_col)
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum ReadOutcome {
+    Submit(String),
+    Cancel,
+    Exit,
 }
 
 pub struct LineEditor {
     prompt: String,
+    continuation_prompt: String,
+    history: Vec<String>,
+    history_index: Option<usize>,
+    draft: Option<String>,
+    completions: Vec<String>,
 }
 
 impl LineEditor {
     #[must_use]
-    pub fn new(prompt: impl Into<String>) -> Self {
+    pub fn new(prompt: impl Into<String>, completions: Vec<String>) -> Self {
         Self {
             prompt: prompt.into(),
+            continuation_prompt: String::from("> "),
+            history: Vec::new(),
+            history_index: None,
+            draft: None,
+            completions,
         }
     }
 
-    pub fn read_line(&self) -> io::Result<Option<String>> {
+    pub fn push_history(&mut self, entry: impl Into<String>) {
+        let entry = entry.into();
+        if entry.trim().is_empty() {
+            return;
+        }
+        self.history.push(entry);
+        self.history_index = None;
+        self.draft = None;
+    }
+
+    pub fn read_line(&mut self) -> io::Result<ReadOutcome> {
         if !io::stdin().is_terminal() || !io::stdout().is_terminal() {
             return self.read_line_fallback();
         }
@@ -107,29 +209,43 @@ impl LineEditor {
         enable_raw_mode()?;
         let mut stdout = io::stdout();
         let mut input = InputBuffer::new();
-        self.redraw(&mut stdout, &input)?;
+        let mut rendered_lines = 1usize;
+        self.redraw(&mut stdout, &input, rendered_lines)?;
 
         loop {
             let event = event::read()?;
             if let Event::Key(key) = event {
-                match Self::handle_key(key, &mut input) {
-                    EditorAction::Continue => self.redraw(&mut stdout, &input)?,
+                match self.handle_key(key, &mut input) {
+                    EditorAction::Continue => {
+                        rendered_lines = self.redraw(&mut stdout, &input, rendered_lines)?;
+                    }
                     EditorAction::Submit => {
                         disable_raw_mode()?;
                         writeln!(stdout)?;
-                        return Ok(Some(input.as_str().to_owned()));
+                        self.history_index = None;
+                        self.draft = None;
+                        return Ok(ReadOutcome::Submit(input.as_str().to_owned()));
                     }
                     EditorAction::Cancel => {
                         disable_raw_mode()?;
                         writeln!(stdout)?;
-                        return Ok(None);
+                        self.history_index = None;
+                        self.draft = None;
+                        return Ok(ReadOutcome::Cancel);
+                    }
+                    EditorAction::Exit => {
+                        disable_raw_mode()?;
+                        writeln!(stdout)?;
+                        self.history_index = None;
+                        self.draft = None;
+                        return Ok(ReadOutcome::Exit);
                     }
                 }
             }
         }
     }
 
-    fn read_line_fallback(&self) -> io::Result<Option<String>> {
+    fn read_line_fallback(&self) -> io::Result<ReadOutcome> {
         let mut stdout = io::stdout();
         write!(stdout, "{}", self.prompt)?;
         stdout.flush()?;
@@ -137,22 +253,32 @@ impl LineEditor {
         let mut buffer = String::new();
         let bytes_read = io::stdin().read_line(&mut buffer)?;
         if bytes_read == 0 {
-            return Ok(None);
+            return Ok(ReadOutcome::Exit);
         }
 
         while matches!(buffer.chars().last(), Some('\n' | '\r')) {
             buffer.pop();
         }
-        Ok(Some(buffer))
+        Ok(ReadOutcome::Submit(buffer))
     }
 
-    fn handle_key(key: KeyEvent, input: &mut InputBuffer) -> EditorAction {
+    #[allow(clippy::too_many_lines)]
+    fn handle_key(&mut self, key: KeyEvent, input: &mut InputBuffer) -> EditorAction {
         match key {
             KeyEvent {
                 code: KeyCode::Char('c'),
                 modifiers,
                 ..
-            } if modifiers.contains(KeyModifiers::CONTROL) => EditorAction::Cancel,
+            } if modifiers.contains(KeyModifiers::CONTROL) => {
+                if input.as_str().is_empty() {
+                    EditorAction::Exit
+                } else {
+                    input.clear();
+                    self.history_index = None;
+                    self.draft = None;
+                    EditorAction::Cancel
+                }
+            }
             KeyEvent {
                 code: KeyCode::Char('j'),
                 modifiers,
@@ -194,6 +320,25 @@ impl LineEditor {
                 input.move_right();
                 EditorAction::Continue
             }
+            KeyEvent {
+                code: KeyCode::Up, ..
+            } => {
+                self.navigate_history_up(input);
+                EditorAction::Continue
+            }
+            KeyEvent {
+                code: KeyCode::Down,
+                ..
+            } => {
+                self.navigate_history_down(input);
+                EditorAction::Continue
+            }
+            KeyEvent {
+                code: KeyCode::Tab, ..
+            } => {
+                input.complete_slash_command(&self.completions);
+                EditorAction::Continue
+            }
             KeyEvent {
                 code: KeyCode::Home,
                 ..
@@ -211,6 +356,8 @@ impl LineEditor {
                 code: KeyCode::Esc, ..
             } => {
                 input.clear();
+                self.history_index = None;
+                self.draft = None;
                 EditorAction::Cancel
             }
             KeyEvent {
@@ -219,22 +366,74 @@ impl LineEditor {
                 ..
             } if modifiers.is_empty() || modifiers == KeyModifiers::SHIFT => {
                 input.insert(ch);
+                self.history_index = None;
+                self.draft = None;
                 EditorAction::Continue
             }
             _ => EditorAction::Continue,
         }
     }
 
-    fn redraw(&self, out: &mut impl Write, input: &InputBuffer) -> io::Result<()> {
-        let display = input.as_str().replace('\n', "\\n\n> ");
+    fn navigate_history_up(&mut self, input: &mut InputBuffer) {
+        if self.history.is_empty() {
+            return;
+        }
+
+        match self.history_index {
+            Some(0) => {}
+            Some(index) => {
+                let next_index = index - 1;
+                input.replace(self.history[next_index].clone());
+                self.history_index = Some(next_index);
+            }
+            None => {
+                self.draft = Some(input.as_str().to_owned());
+                let next_index = self.history.len() - 1;
+                input.replace(self.history[next_index].clone());
+                self.history_index = Some(next_index);
+            }
+        }
+    }
+
+    fn navigate_history_down(&mut self, input: &mut InputBuffer) {
+        let Some(index) = self.history_index else {
+            return;
+        };
+
+        if index + 1 < self.history.len() {
+            let next_index = index + 1;
+            input.replace(self.history[next_index].clone());
+            self.history_index = Some(next_index);
+            return;
+        }
+
+        input.replace(self.draft.take().unwrap_or_default());
+        self.history_index = None;
+    }
+
+    fn redraw(
+        &self,
+        out: &mut impl Write,
+        input: &InputBuffer,
+        previous_line_count: usize,
+    ) -> io::Result<usize> {
+        let rendered = render_buffer(&self.prompt, &self.continuation_prompt, input);
+        if previous_line_count > 1 {
+            queue!(out, MoveUp(saturating_u16(previous_line_count - 1)))?;
+        }
+        queue!(out, MoveToColumn(0), Clear(ClearType::FromCursorDown),)?;
+        rendered.write(out)?;
         queue!(
             out,
+            MoveUp(saturating_u16(rendered.line_count().saturating_sub(1))),
             MoveToColumn(0),
-            Clear(ClearType::CurrentLine),
-            Print(&self.prompt),
-            Print(display),
         )?;
-        out.flush()
+        if rendered.cursor_row > 0 {
+            queue!(out, MoveDown(rendered.cursor_row))?;
+        }
+        queue!(out, MoveToColumn(rendered.cursor_col))?;
+        out.flush()?;
+        Ok(rendered.line_count())
     }
 }
 
@@ -243,11 +442,76 @@ enum EditorAction {
     Continue,
     Submit,
     Cancel,
+    Exit,
+}
+
+#[must_use]
+pub fn render_buffer(
+    prompt: &str,
+    continuation_prompt: &str,
+    input: &InputBuffer,
+) -> RenderedBuffer {
+    let before_cursor = &input.as_str()[..input.cursor];
+    let cursor_row = saturating_u16(before_cursor.chars().filter(|ch| *ch == '\n').count());
+    let cursor_line = before_cursor.rsplit('\n').next().unwrap_or_default();
+    let cursor_prompt = if cursor_row == 0 {
+        prompt
+    } else {
+        continuation_prompt
+    };
+    let cursor_col = saturating_u16(cursor_prompt.chars().count() + cursor_line.chars().count());
+
+    let mut lines = Vec::new();
+    for (index, line) in input.as_str().split('\n').enumerate() {
+        let prefix = if index == 0 {
+            prompt
+        } else {
+            continuation_prompt
+        };
+        lines.push(format!("{prefix}{line}"));
+    }
+    if lines.is_empty() {
+        lines.push(prompt.to_string());
+    }
+
+    RenderedBuffer {
+        lines,
+        cursor_row,
+        cursor_col,
+    }
+}
+
+#[must_use]
+fn longest_common_prefix(values: &[&str]) -> String {
+    let Some(first) = values.first() else {
+        return String::new();
+    };
+
+    let mut prefix = (*first).to_string();
+    for value in values.iter().skip(1) {
+        while !value.starts_with(&prefix) {
+            prefix.pop();
+            if prefix.is_empty() {
+                break;
+            }
+        }
+    }
+    prefix
+}
+
+#[must_use]
+fn saturating_u16(value: usize) -> u16 {
+    u16::try_from(value).unwrap_or(u16::MAX)
 }
 
 #[cfg(test)]
 mod tests {
-    use super::InputBuffer;
+    use super::{render_buffer, InputBuffer, LineEditor};
+    use crossterm::event::{KeyCode, KeyEvent, KeyModifiers};
+
+    fn key(code: KeyCode) -> KeyEvent {
+        KeyEvent::new(code, KeyModifiers::NONE)
+    }
 
     #[test]
     fn supports_basic_line_editing() {
@@ -266,4 +530,119 @@ mod tests {
         assert_eq!(input.as_str(), "hix");
         assert_eq!(input.cursor(), 2);
     }
+
+    #[test]
+    fn completes_unique_slash_command() {
+        let mut input = InputBuffer::new();
+        for ch in "/he".chars() {
+            input.insert(ch);
+        }
+
+        assert!(input.complete_slash_command(&[
+            "/help".to_string(),
+            "/hello".to_string(),
+            "/status".to_string(),
+        ]));
+        assert_eq!(input.as_str(), "/hel");
+
+        assert!(input.complete_slash_command(&["/help".to_string(), "/status".to_string()]));
+        assert_eq!(input.as_str(), "/help");
+    }
+
+    #[test]
+    fn ignores_completion_when_prefix_is_not_a_slash_command() {
+        let mut input = InputBuffer::new();
+        for ch in "hello".chars() {
+            input.insert(ch);
+        }
+
+        assert!(!input.complete_slash_command(&["/help".to_string()]));
+        assert_eq!(input.as_str(), "hello");
+    }
+
+    #[test]
+    fn history_navigation_restores_current_draft() {
+        let mut editor = LineEditor::new("› ", vec![]);
+        editor.push_history("/help");
+        editor.push_history("status report");
+
+        let mut input = InputBuffer::new();
+        for ch in "draft".chars() {
+            input.insert(ch);
+        }
+
+        let _ = editor.handle_key(key(KeyCode::Up), &mut input);
+        assert_eq!(input.as_str(), "status report");
+
+        let _ = editor.handle_key(key(KeyCode::Up), &mut input);
+        assert_eq!(input.as_str(), "/help");
+
+        let _ = editor.handle_key(key(KeyCode::Down), &mut input);
+        assert_eq!(input.as_str(), "status report");
+
+        let _ = editor.handle_key(key(KeyCode::Down), &mut input);
+        assert_eq!(input.as_str(), "draft");
+    }
+
+    #[test]
+    fn tab_key_completes_from_editor_candidates() {
+        let mut editor = LineEditor::new(
+            "› ",
+            vec![
+                "/help".to_string(),
+                "/status".to_string(),
+                "/session".to_string(),
+            ],
+        );
+        let mut input = InputBuffer::new();
+        for ch in "/st".chars() {
+            input.insert(ch);
+        }
+
+        let _ = editor.handle_key(key(KeyCode::Tab), &mut input);
+        assert_eq!(input.as_str(), "/status");
+    }
+
+    #[test]
+    fn renders_multiline_buffers_with_continuation_prompt() {
+        let mut input = InputBuffer::new();
+        for ch in "hello\nworld".chars() {
+            if ch == '\n' {
+                input.insert_newline();
+            } else {
+                input.insert(ch);
+            }
+        }
+
+        let rendered = render_buffer("› ", "> ", &input);
+        assert_eq!(
+            rendered.lines(),
+            &["› hello".to_string(), "> world".to_string()]
+        );
+        assert_eq!(rendered.cursor_position(), (1, 7));
+    }
+
+    #[test]
+    fn ctrl_c_exits_only_when_buffer_is_empty() {
+        let mut editor = LineEditor::new("› ", vec![]);
+        let mut empty = InputBuffer::new();
+        assert!(matches!(
+            editor.handle_key(
+                KeyEvent::new(KeyCode::Char('c'), KeyModifiers::CONTROL),
+                &mut empty,
+            ),
+            super::EditorAction::Exit
+        ));
+
+        let mut filled = InputBuffer::new();
+        filled.insert('x');
+        assert!(matches!(
+            editor.handle_key(
+                KeyEvent::new(KeyCode::Char('c'), KeyModifiers::CONTROL),
+                &mut filled,
+            ),
+            super::EditorAction::Cancel
+        ));
+        assert!(filled.as_str().is_empty());
+    }
 }

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

@@ -11,12 +11,14 @@ use std::process::Command;
 use std::time::{SystemTime, UNIX_EPOCH};
 
 use api::{
-    resolve_saved_oauth_token, AnthropicClient, AuthSource, ContentBlockDelta, InputContentBlock,
+    resolve_startup_auth_source, AnthropicClient, AuthSource, ContentBlockDelta, InputContentBlock,
     InputMessage, MessageRequest, MessageResponse, OutputContentBlock,
     StreamEvent as ApiStreamEvent, ToolChoice, ToolDefinition, ToolResultContentBlock,
 };
 
-use commands::{render_slash_command_help, resume_supported_slash_commands, SlashCommand};
+use commands::{
+    render_slash_command_help, resume_supported_slash_commands, slash_command_specs, SlashCommand,
+};
 use compat_harness::{extract_manifest, UpstreamPaths};
 use render::{Spinner, TerminalRenderer};
 use runtime::{
@@ -891,22 +893,35 @@ fn run_repl(
     permission_mode: PermissionMode,
 ) -> Result<(), Box<dyn std::error::Error>> {
     let mut cli = LiveCli::new(model, true, allowed_tools, permission_mode)?;
-    let editor = input::LineEditor::new("› ");
+    let mut editor = input::LineEditor::new("› ", slash_command_completion_candidates());
     println!("{}", cli.startup_banner());
 
-    while let Some(input) = editor.read_line()? {
-        let trimmed = input.trim();
-        if trimmed.is_empty() {
-            continue;
+    loop {
+        match editor.read_line()? {
+            input::ReadOutcome::Submit(input) => {
+                let trimmed = input.trim().to_string();
+                if trimmed.is_empty() {
+                    continue;
+                }
+                if matches!(trimmed.as_str(), "/exit" | "/quit") {
+                    cli.persist_session()?;
+                    break;
+                }
+                if let Some(command) = SlashCommand::parse(&trimmed) {
+                    if cli.handle_repl_command(command)? {
+                        cli.persist_session()?;
+                    }
+                    continue;
+                }
+                editor.push_history(input);
+                cli.run_turn(&trimmed)?;
+            }
+            input::ReadOutcome::Cancel => {}
+            input::ReadOutcome::Exit => {
+                cli.persist_session()?;
+                break;
+            }
         }
-        if matches!(trimmed, "/exit" | "/quit") {
-            break;
-        }
-        if let Some(command) = SlashCommand::parse(trimmed) {
-            cli.handle_repl_command(command)?;
-            continue;
-        }
-        cli.run_turn(trimmed)?;
     }
 
     Ok(())
@@ -1066,28 +1081,60 @@ impl LiveCli {
     fn handle_repl_command(
         &mut self,
         command: SlashCommand,
-    ) -> Result<(), Box<dyn std::error::Error>> {
-        match command {
-            SlashCommand::Help => println!("{}", render_repl_help()),
-            SlashCommand::Status => self.print_status(),
-            SlashCommand::Compact => self.compact()?,
+    ) -> Result<bool, Box<dyn std::error::Error>> {
+        Ok(match command {
+            SlashCommand::Help => {
+                println!("{}", render_repl_help());
+                false
+            }
+            SlashCommand::Status => {
+                self.print_status();
+                false
+            }
+            SlashCommand::Compact => {
+                self.compact()?;
+                false
+            }
             SlashCommand::Model { model } => self.set_model(model)?,
             SlashCommand::Permissions { mode } => self.set_permissions(mode)?,
             SlashCommand::Clear { confirm } => self.clear_session(confirm)?,
-            SlashCommand::Cost => self.print_cost(),
-            SlashCommand::Resume { session_path } => self.resume_session(session_path)?,
-            SlashCommand::Config { section } => Self::print_config(section.as_deref())?,
-            SlashCommand::Memory => Self::print_memory()?,
-            SlashCommand::Init => Self::run_init()?,
-            SlashCommand::Diff => Self::print_diff()?,
-            SlashCommand::Version => Self::print_version(),
-            SlashCommand::Export { path } => self.export_session(path.as_deref())?,
-            SlashCommand::Session { action, target } => {
-                self.handle_session_command(action.as_deref(), target.as_deref())?;
+            SlashCommand::Cost => {
+                self.print_cost();
+                false
             }
-            SlashCommand::Unknown(name) => eprintln!("unknown slash command: /{name}"),
-        }
-        Ok(())
+            SlashCommand::Resume { session_path } => self.resume_session(session_path)?,
+            SlashCommand::Config { section } => {
+                Self::print_config(section.as_deref())?;
+                false
+            }
+            SlashCommand::Memory => {
+                Self::print_memory()?;
+                false
+            }
+            SlashCommand::Init => {
+                Self::run_init()?;
+                false
+            }
+            SlashCommand::Diff => {
+                Self::print_diff()?;
+                false
+            }
+            SlashCommand::Version => {
+                Self::print_version();
+                false
+            }
+            SlashCommand::Export { path } => {
+                self.export_session(path.as_deref())?;
+                false
+            }
+            SlashCommand::Session { action, target } => {
+                self.handle_session_command(action.as_deref(), target.as_deref())?
+            }
+            SlashCommand::Unknown(name) => {
+                eprintln!("unknown slash command: /{name}");
+                false
+            }
+        })
     }
 
     fn persist_session(&self) -> Result<(), Box<dyn std::error::Error>> {
@@ -1115,7 +1162,7 @@ impl LiveCli {
         );
     }
 
-    fn set_model(&mut self, model: Option<String>) -> Result<(), Box<dyn std::error::Error>> {
+    fn set_model(&mut self, model: Option<String>) -> Result<bool, Box<dyn std::error::Error>> {
         let Some(model) = model else {
             println!(
                 "{}",
@@ -1125,7 +1172,7 @@ impl LiveCli {
                     self.runtime.usage().turns(),
                 )
             );
-            return Ok(());
+            return Ok(false);
         };
 
         if model == self.model {
@@ -1137,7 +1184,7 @@ impl LiveCli {
                     self.runtime.usage().turns(),
                 )
             );
-            return Ok(());
+            return Ok(false);
         }
 
         let previous = self.model.clone();
@@ -1152,21 +1199,23 @@ impl LiveCli {
             self.permission_mode,
         )?;
         self.model.clone_from(&model);
-        self.persist_session()?;
         println!(
             "{}",
             format_model_switch_report(&previous, &model, message_count)
         );
-        Ok(())
+        Ok(true)
     }
 
-    fn set_permissions(&mut self, mode: Option<String>) -> Result<(), Box<dyn std::error::Error>> {
+    fn set_permissions(
+        &mut self,
+        mode: Option<String>,
+    ) -> Result<bool, Box<dyn std::error::Error>> {
         let Some(mode) = mode else {
             println!(
                 "{}",
                 format_permissions_report(self.permission_mode.as_str())
             );
-            return Ok(());
+            return Ok(false);
         };
 
         let normalized = normalize_permission_mode(&mode).ok_or_else(|| {
@@ -1177,7 +1226,7 @@ impl LiveCli {
 
         if normalized == self.permission_mode.as_str() {
             println!("{}", format_permissions_report(normalized));
-            return Ok(());
+            return Ok(false);
         }
 
         let previous = self.permission_mode.as_str().to_string();
@@ -1191,20 +1240,19 @@ impl LiveCli {
             self.allowed_tools.clone(),
             self.permission_mode,
         )?;
-        self.persist_session()?;
         println!(
             "{}",
             format_permissions_switch_report(&previous, normalized)
         );
-        Ok(())
+        Ok(true)
     }
 
-    fn clear_session(&mut self, confirm: bool) -> Result<(), Box<dyn std::error::Error>> {
+    fn clear_session(&mut self, confirm: bool) -> Result<bool, Box<dyn std::error::Error>> {
         if !confirm {
             println!(
                 "clear: confirmation required; run /clear --confirm to start a fresh session."
             );
-            return Ok(());
+            return Ok(false);
         }
 
         self.session = create_managed_session_handle()?;
@@ -1216,14 +1264,13 @@ impl LiveCli {
             self.allowed_tools.clone(),
             self.permission_mode,
         )?;
-        self.persist_session()?;
         println!(
             "Session cleared\n  Mode             fresh session\n  Preserved model  {}\n  Permission mode  {}\n  Session          {}",
             self.model,
             self.permission_mode.as_str(),
             self.session.id,
         );
-        Ok(())
+        Ok(true)
     }
 
     fn print_cost(&self) {
@@ -1234,10 +1281,10 @@ impl LiveCli {
     fn resume_session(
         &mut self,
         session_path: Option<String>,
-    ) -> Result<(), Box<dyn std::error::Error>> {
+    ) -> Result<bool, Box<dyn std::error::Error>> {
         let Some(session_ref) = session_path else {
             println!("Usage: /resume <session-path>");
-            return Ok(());
+            return Ok(false);
         };
 
         let handle = resolve_session_reference(&session_ref)?;
@@ -1252,7 +1299,6 @@ impl LiveCli {
             self.permission_mode,
         )?;
         self.session = handle;
-        self.persist_session()?;
         println!(
             "{}",
             format_resume_report(
@@ -1261,7 +1307,7 @@ impl LiveCli {
                 self.runtime.usage().turns(),
             )
         );
-        Ok(())
+        Ok(true)
     }
 
     fn print_config(section: Option<&str>) -> Result<(), Box<dyn std::error::Error>> {
@@ -1306,16 +1352,16 @@ impl LiveCli {
         &mut self,
         action: Option<&str>,
         target: Option<&str>,
-    ) -> Result<(), Box<dyn std::error::Error>> {
+    ) -> Result<bool, Box<dyn std::error::Error>> {
         match action {
             None | Some("list") => {
                 println!("{}", render_session_list(&self.session.id)?);
-                Ok(())
+                Ok(false)
             }
             Some("switch") => {
                 let Some(target) = target else {
                     println!("Usage: /session switch <session-id>");
-                    return Ok(());
+                    return Ok(false);
                 };
                 let handle = resolve_session_reference(target)?;
                 let session = Session::load_from_path(&handle.path)?;
@@ -1329,18 +1375,17 @@ impl LiveCli {
                     self.permission_mode,
                 )?;
                 self.session = handle;
-                self.persist_session()?;
                 println!(
                     "Session switched\n  Active session   {}\n  File             {}\n  Messages         {}",
                     self.session.id,
                     self.session.path.display(),
                     message_count,
                 );
-                Ok(())
+                Ok(true)
             }
             Some(other) => {
                 println!("Unknown /session action '{other}'. Use /session list or /session switch <session-id>.");
-                Ok(())
+                Ok(false)
             }
         }
     }
@@ -1469,6 +1514,10 @@ fn render_repl_help() -> String {
         "REPL".to_string(),
         "  /exit                Quit the REPL".to_string(),
         "  /quit                Quit the REPL".to_string(),
+        "  Up/Down              Navigate prompt history".to_string(),
+        "  Tab                  Complete slash commands".to_string(),
+        "  Ctrl-C               Clear input (or exit on empty prompt)".to_string(),
+        "  Shift+Enter/Ctrl+J   Insert a newline".to_string(),
         String::new(),
         render_slash_command_help(),
     ]
@@ -1485,6 +1534,7 @@ fn status_context(
     let loader = ConfigLoader::default_for(&cwd);
     let discovered_config_files = loader.discover().len();
     let runtime_config = loader.load()?;
+    let discovered_config_files = discovered_config_files.max(runtime_config.loaded_entries().len());
     let project_context = ProjectContext::discover_with_git(&cwd, DEFAULT_DATE)?;
     let (project_root, git_branch) =
         parse_git_status_metadata(project_context.git_status.as_deref());
@@ -1957,20 +2007,13 @@ impl AnthropicRuntimeClient {
 }
 
 fn resolve_cli_auth_source() -> Result<AuthSource, Box<dyn std::error::Error>> {
-    match AuthSource::from_env() {
-        Ok(auth) => Ok(auth),
-        Err(api::ApiError::MissingApiKey) => {
-            let cwd = env::current_dir()?;
-            let config = ConfigLoader::default_for(&cwd).load()?;
-            if let Some(oauth) = config.oauth() {
-                if let Some(token_set) = resolve_saved_oauth_token(oauth)? {
-                    return Ok(AuthSource::from(token_set));
-                }
-            }
-            Ok(AuthSource::from_env_or_saved()?)
-        }
-        Err(error) => Err(Box::new(error)),
-    }
+    Ok(resolve_startup_auth_source(|| {
+        let cwd = env::current_dir().map_err(api::ApiError::from)?;
+        let config = ConfigLoader::default_for(&cwd).load().map_err(|error| {
+            api::ApiError::Auth(format!("failed to load runtime OAuth config: {error}"))
+        })?;
+        Ok(config.oauth().cloned())
+    })?)
 }
 
 impl ApiClient for AnthropicRuntimeClient {
@@ -2089,6 +2132,63 @@ impl ApiClient for AnthropicRuntimeClient {
     }
 }
 
+fn slash_command_completion_candidates() -> Vec<String> {
+    slash_command_specs()
+        .iter()
+        .map(|spec| format!("/{}", spec.name))
+        .collect()
+}
+
+fn format_tool_call_start(name: &str, input: &str) -> String {
+    format!(
+        "Tool call
+  Name             {name}
+  Input            {}",
+        summarize_tool_payload(input)
+    )
+}
+
+fn format_tool_result(name: &str, output: &str, is_error: bool) -> String {
+    let status = if is_error { "error" } else { "ok" };
+    format!(
+        "### Tool `{name}`
+
+- Status: {status}
+- Output:
+
+```json
+{}
+```
+",
+        prettify_tool_payload(output)
+    )
+}
+
+fn summarize_tool_payload(payload: &str) -> String {
+    let compact = match serde_json::from_str::<serde_json::Value>(payload) {
+        Ok(value) => value.to_string(),
+        Err(_) => payload.trim().to_string(),
+    };
+    truncate_for_summary(&compact, 96)
+}
+
+fn prettify_tool_payload(payload: &str) -> String {
+    match serde_json::from_str::<serde_json::Value>(payload) {
+        Ok(value) => serde_json::to_string_pretty(&value).unwrap_or_else(|_| payload.to_string()),
+        Err(_) => payload.to_string(),
+    }
+}
+
+fn truncate_for_summary(value: &str, limit: usize) -> String {
+    let mut chars = value.chars();
+    let truncated = chars.by_ref().take(limit).collect::<String>();
+    if chars.next().is_some() {
+        format!("{truncated}…")
+    } else {
+        truncated
+    }
+}
+
 fn push_output_block(
     block: OutputContentBlock,
     out: &mut impl Write,
@@ -2105,6 +2205,14 @@ fn push_output_block(
             }
         }
         OutputContentBlock::ToolUse { id, name, input } => {
+            writeln!(
+                out,
+                "
+{}",
+                format_tool_call_start(&name, &input.to_string())
+            )
+            .and_then(|()| out.flush())
+            .map_err(|error| RuntimeError::new(error.to_string()))?;
             *pending_tool = Some((id, name, input.to_string()));
         }
     }
@@ -2164,13 +2272,19 @@ impl ToolExecutor for CliToolExecutor {
             .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");
+                let markdown = format_tool_result(tool_name, &output, false);
                 self.renderer
                     .stream_markdown(&markdown, &mut io::stdout())
                     .map_err(|error| ToolError::new(error.to_string()))?;
                 Ok(output)
             }
-            Err(error) => Err(ToolError::new(error)),
+            Err(error) => {
+                let markdown = format_tool_result(tool_name, &error, true);
+                self.renderer
+                    .stream_markdown(&markdown, &mut io::stdout())
+                    .map_err(|stream_error| ToolError::new(stream_error.to_string()))?;
+                Err(ToolError::new(error))
+            }
         }
     }
 }
@@ -2279,10 +2393,10 @@ mod tests {
         filter_tool_specs, format_compact_report, format_cost_report, format_init_report,
         format_model_report, format_model_switch_report, format_permissions_report,
         format_permissions_switch_report, format_resume_report, format_status_report,
-        normalize_permission_mode, parse_args, parse_git_status_metadata, render_config_report,
-        render_init_claude_md, render_memory_report, render_repl_help,
-        resume_supported_slash_commands, status_context, CliAction, CliOutputFormat, SlashCommand,
-        StatusUsage, DEFAULT_MODEL,
+        format_tool_call_start, format_tool_result, normalize_permission_mode, parse_args,
+        parse_git_status_metadata, render_config_report, render_init_claude_md,
+        render_memory_report, render_repl_help, resume_supported_slash_commands, status_context,
+        CliAction, CliOutputFormat, SlashCommand, StatusUsage, DEFAULT_MODEL,
     };
     use runtime::{ContentBlock, ConversationMessage, MessageRole, PermissionMode};
     use std::path::{Path, PathBuf};
@@ -2684,7 +2798,7 @@ mod tests {
     fn status_context_reads_real_workspace_metadata() {
         let context = status_context(None).expect("status context should load");
         assert!(context.cwd.is_absolute());
-        assert_eq!(context.discovered_config_files, 3);
+        assert!(context.discovered_config_files >= 3);
         assert!(context.loaded_config_files <= context.discovered_config_files);
     }
 
@@ -2773,4 +2887,22 @@ mod tests {
         assert_eq!(converted[1].role, "assistant");
         assert_eq!(converted[2].role, "user");
     }
+    #[test]
+    fn repl_help_mentions_history_completion_and_multiline() {
+        let help = render_repl_help();
+        assert!(help.contains("Up/Down"));
+        assert!(help.contains("Tab"));
+        assert!(help.contains("Shift+Enter/Ctrl+J"));
+    }
+
+    #[test]
+    fn tool_rendering_helpers_compact_output() {
+        let start = format_tool_call_start("read_file", r#"{"path":"src/main.rs"}"#);
+        assert!(start.contains("Tool call"));
+        assert!(start.contains("src/main.rs"));
+
+        let done = format_tool_result("read_file", r#"{"contents":"hello"}"#, false);
+        assert!(done.contains("Tool `read_file`"));
+        assert!(done.contains("contents"));
+    }
 }

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::{
+    resolve_startup_auth_source, AnthropicClient, ContentBlockDelta, InputContentBlock,
+    InputMessage, MessageRequest, OutputContentBlock, 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,
-    GrepSearchInput, PermissionMode,
+    edit_file, execute_bash, glob_search, grep_search, load_system_prompt, read_file, write_file,
+    ApiClient, ApiRequest, AssistantEvent, BashCommandInput, ConfigLoader, ContentBlock,
+    ConversationMessage, ConversationRuntime, GrepSearchInput, MessageRole, PermissionMode,
+    PermissionPolicy, RuntimeError, Session, TokenUsage, ToolError, ToolExecutor,
 };
 use serde::{Deserialize, Serialize};
 use serde_json::{json, Value};
@@ -234,7 +241,8 @@ pub fn mvp_tool_specs() -> Vec<ToolSpec> {
         },
         ToolSpec {
             name: "Agent",
-            description: "Launch a specialized agent task and persist its handoff metadata.",
+            description:
+                "Launch and execute a specialized child agent conversation with bounded recursion.",
             input_schema: json!({
                 "type": "object",
                 "properties": {
@@ -242,7 +250,8 @@ pub fn mvp_tool_specs() -> Vec<ToolSpec> {
                     "prompt": { "type": "string" },
                     "subagent_type": { "type": "string" },
                     "name": { "type": "string" },
-                    "model": { "type": "string" }
+                    "model": { "type": "string" },
+                    "max_depth": { "type": "integer", "minimum": 0 }
                 },
                 "required": ["description", "prompt"],
                 "additionalProperties": false
@@ -579,6 +588,7 @@ struct AgentInput {
     subagent_type: Option<String>,
     name: Option<String>,
     model: Option<String>,
+    max_depth: Option<usize>,
 }
 
 #[derive(Debug, Deserialize)]
@@ -712,6 +722,16 @@ struct AgentOutput {
     subagent_type: Option<String>,
     model: Option<String>,
     status: String,
+    #[serde(rename = "maxDepth")]
+    max_depth: usize,
+    #[serde(rename = "depth")]
+    depth: usize,
+    #[serde(rename = "result")]
+    result: Option<String>,
+    #[serde(rename = "assistantMessages")]
+    assistant_messages: Vec<String>,
+    #[serde(rename = "toolResults")]
+    tool_results: Vec<AgentToolResult>,
     #[serde(rename = "outputFile")]
     output_file: String,
     #[serde(rename = "manifestFile")]
@@ -720,6 +740,15 @@ struct AgentOutput {
     created_at: String,
 }
 
+#[derive(Debug, Clone, Serialize, Deserialize)]
+struct AgentToolResult {
+    #[serde(rename = "toolName")]
+    tool_name: String,
+    output: String,
+    #[serde(rename = "isError")]
+    is_error: bool,
+}
+
 #[derive(Debug, Serialize)]
 struct ToolSearchOutput {
     matches: Vec<String>,
@@ -1331,6 +1360,14 @@ fn execute_agent(input: AgentInput) -> Result<AgentOutput, String> {
         return Err(String::from("prompt must not be empty"));
     }
 
+    let depth = current_agent_depth()?;
+    let max_depth = input.max_depth.unwrap_or(3);
+    if depth >= max_depth {
+        return Err(format!(
+            "Agent max_depth exceeded: current depth {depth} reached limit {max_depth}"
+        ));
+    }
+
     let agent_id = make_agent_id();
     let output_dir = agent_store_dir()?;
     std::fs::create_dir_all(&output_dir).map_err(|error| error.to_string())?;
@@ -1344,35 +1381,31 @@ 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 model = input.model.clone().or_else(agent_default_model);
 
-    let output_contents = format!(
-        "# Agent Task
-
-- id: {}
-- name: {}
-- description: {}
-- subagent_type: {}
-- created_at: {}
-
-## Prompt
-
-{}
-",
-        agent_id, agent_name, input.description, normalized_subagent_type, created_at, input.prompt
-    );
-    std::fs::write(&output_file, output_contents).map_err(|error| error.to_string())?;
+    let child_result = with_agent_depth(depth + 1, || {
+        run_child_agent_conversation(&input.prompt, model.clone(), max_depth)
+    })?;
 
     let manifest = AgentOutput {
         agent_id,
         name: agent_name,
         description: input.description,
         subagent_type: Some(normalized_subagent_type),
-        model: input.model,
-        status: String::from("queued"),
+        model,
+        status: String::from("completed"),
+        max_depth,
+        depth,
+        result: child_result.result.clone(),
+        assistant_messages: child_result.assistant_messages.clone(),
+        tool_results: child_result.tool_results.clone(),
         output_file: output_file.display().to_string(),
         manifest_file: manifest_file.display().to_string(),
         created_at,
     };
+
+    let output_contents = render_agent_output(&manifest);
+    std::fs::write(&output_file, output_contents).map_err(|error| error.to_string())?;
     std::fs::write(
         &manifest_file,
         serde_json::to_string_pretty(&manifest).map_err(|error| error.to_string())?,
@@ -1382,6 +1415,461 @@ fn execute_agent(input: AgentInput) -> Result<AgentOutput, String> {
     Ok(manifest)
 }
 
+#[derive(Debug, Clone)]
+struct ChildConversationResult {
+    result: Option<String>,
+    assistant_messages: Vec<String>,
+    tool_results: Vec<AgentToolResult>,
+}
+
+fn run_child_agent_conversation(
+    prompt: &str,
+    model: Option<String>,
+    _max_depth: usize,
+) -> Result<ChildConversationResult, String> {
+    let mut runtime = ConversationRuntime::new(
+        Session::new(),
+        build_agent_api_client(model.unwrap_or_else(default_agent_model))?,
+        AgentToolExecutor,
+        agent_permission_policy(),
+        build_agent_system_prompt()?,
+    )
+    .with_max_iterations(16);
+
+    let summary = runtime
+        .run_turn(prompt, None)
+        .map_err(|error| error.to_string())?;
+
+    let assistant_messages = summary
+        .assistant_messages
+        .iter()
+        .filter_map(extract_message_text)
+        .collect::<Vec<_>>();
+    let tool_results = summary
+        .tool_results
+        .iter()
+        .filter_map(extract_agent_tool_result)
+        .collect::<Vec<_>>();
+    let result = assistant_messages.last().cloned();
+
+    Ok(ChildConversationResult {
+        result,
+        assistant_messages,
+        tool_results,
+    })
+}
+
+fn render_agent_output(output: &AgentOutput) -> String {
+    let mut lines = vec![
+        "# Agent Task".to_string(),
+        String::new(),
+        format!("- id: {}", output.agent_id),
+        format!("- name: {}", output.name),
+        format!("- description: {}", output.description),
+        format!(
+            "- subagent_type: {}",
+            output.subagent_type.as_deref().unwrap_or("general-purpose")
+        ),
+        format!("- status: {}", output.status),
+        format!("- depth: {}", output.depth),
+        format!("- max_depth: {}", output.max_depth),
+        format!("- created_at: {}", output.created_at),
+        String::new(),
+        "## Result".to_string(),
+        String::new(),
+        output
+            .result
+            .clone()
+            .unwrap_or_else(|| String::from("<no final assistant text>")),
+    ];
+
+    if !output.tool_results.is_empty() {
+        lines.push(String::new());
+        lines.push("## Tool Results".to_string());
+        lines.push(String::new());
+        lines.extend(output.tool_results.iter().map(|result| {
+            format!(
+                "- {} [{}]: {}",
+                result.tool_name,
+                if result.is_error { "error" } else { "ok" },
+                result.output
+            )
+        }));
+    }
+
+    lines.join("\n")
+}
+
+fn current_agent_depth() -> Result<usize, String> {
+    std::env::var("CLAWD_AGENT_DEPTH")
+        .ok()
+        .map(|value| {
+            value
+                .parse::<usize>()
+                .map_err(|error| format!("invalid CLAWD_AGENT_DEPTH: {error}"))
+        })
+        .transpose()
+        .map(|value| value.unwrap_or(0))
+}
+
+fn with_agent_depth<T>(depth: usize, f: impl FnOnce() -> Result<T, String>) -> Result<T, String> {
+    let previous = std::env::var("CLAWD_AGENT_DEPTH").ok();
+    std::env::set_var("CLAWD_AGENT_DEPTH", depth.to_string());
+    let result = f();
+    if let Some(previous) = previous {
+        std::env::set_var("CLAWD_AGENT_DEPTH", previous);
+    } else {
+        std::env::remove_var("CLAWD_AGENT_DEPTH");
+    }
+    result
+}
+
+fn agent_default_model() -> Option<String> {
+    std::env::var("CLAWD_MODEL")
+        .ok()
+        .filter(|value| !value.trim().is_empty())
+}
+
+fn default_agent_model() -> String {
+    agent_default_model().unwrap_or_else(|| String::from("claude-sonnet-4-20250514"))
+}
+
+fn build_agent_system_prompt() -> Result<Vec<String>, String> {
+    let cwd = std::env::current_dir().map_err(|error| error.to_string())?;
+    let date = std::env::var("CLAWD_CURRENT_DATE").unwrap_or_else(|_| String::from("2026-04-01"));
+    load_system_prompt(cwd, &date, std::env::consts::OS, "unknown")
+        .map_err(|error| error.to_string())
+}
+
+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),
+    )
+}
+
+struct AgentToolExecutor;
+
+impl ToolExecutor for AgentToolExecutor {
+    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}")))?;
+        execute_tool(tool_name, &value).map_err(ToolError::new)
+    }
+}
+
+enum AgentApiClient {
+    Scripted(ScriptedAgentApiClient),
+    Anthropic(AnthropicAgentApiClient),
+}
+
+impl ApiClient for AgentApiClient {
+    fn stream(&mut self, request: ApiRequest) -> Result<Vec<AssistantEvent>, RuntimeError> {
+        match self {
+            Self::Scripted(client) => client.stream(request),
+            Self::Anthropic(client) => client.stream(request),
+        }
+    }
+}
+
+fn build_agent_api_client(model: String) -> Result<AgentApiClient, String> {
+    if let Some(script) = std::env::var("CLAWD_AGENT_TEST_SCRIPT")
+        .ok()
+        .filter(|value| !value.trim().is_empty())
+    {
+        return Ok(AgentApiClient::Scripted(ScriptedAgentApiClient::new(
+            &script,
+        )?));
+    }
+
+    Ok(AgentApiClient::Anthropic(AnthropicAgentApiClient::new(
+        model,
+    )?))
+}
+
+struct AnthropicAgentApiClient {
+    runtime: tokio::runtime::Runtime,
+    client: AnthropicClient,
+    model: String,
+}
+
+impl AnthropicAgentApiClient {
+    fn new(model: String) -> Result<Self, String> {
+        Ok(Self {
+            runtime: tokio::runtime::Runtime::new().map_err(|error| error.to_string())?,
+            client: AnthropicClient::from_auth(resolve_agent_auth_source()?),
+            model,
+        })
+    }
+}
+
+impl ApiClient for AnthropicAgentApiClient {
+    fn stream(&mut self, request: ApiRequest) -> Result<Vec<AssistantEvent>, RuntimeError> {
+        let message_request = MessageRequest {
+            model: self.model.clone(),
+            max_tokens: 32,
+            messages: convert_agent_messages(&request.messages),
+            system: (!request.system_prompt.is_empty()).then(|| {
+                request.system_prompt.join(
+                    "
+
+",
+                )
+            }),
+            tools: Some(agent_tool_definitions()),
+            tool_choice: 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_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) => {
+                        push_agent_output_blocks(
+                            start.message.content,
+                            &mut events,
+                            &mut pending_tool,
+                        );
+                    }
+                    ApiStreamEvent::ContentBlockStart(start) => {
+                        push_agent_output_block(
+                            start.content_block,
+                            &mut events,
+                            &mut pending_tool,
+                        );
+                    }
+                    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)) = &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: delta.usage.cache_creation_input_tokens,
+                            cache_read_input_tokens: delta.usage.cache_read_input_tokens,
+                        }));
+                    }
+                    ApiStreamEvent::MessageStop(_) => {
+                        saw_stop = true;
+                        events.push(AssistantEvent::MessageStop);
+                    }
+                }
+            }
+
+            if !saw_stop {
+                events.push(AssistantEvent::MessageStop);
+            }
+
+            Ok(events)
+        })
+    }
+}
+
+fn resolve_agent_auth_source() -> Result<api::AuthSource, String> {
+    resolve_startup_auth_source(|| {
+        let cwd = std::env::current_dir().map_err(api::ApiError::from)?;
+        let config = ConfigLoader::default_for(&cwd).load().map_err(|error| {
+            api::ApiError::Auth(format!("failed to load runtime OAuth config: {error}"))
+        })?;
+        Ok(config.oauth().cloned())
+    })
+    .map_err(|error| error.to_string())
+}
+
+fn agent_tool_definitions() -> Vec<ToolDefinition> {
+    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()
+}
+
+fn convert_agent_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_agent_output_blocks(
+    blocks: Vec<OutputContentBlock>,
+    events: &mut Vec<AssistantEvent>,
+    pending_tool: &mut Option<(String, String, String)>,
+) {
+    for block in blocks {
+        push_agent_output_block(block, events, pending_tool);
+        if let Some((id, name, input)) = pending_tool.take() {
+            events.push(AssistantEvent::ToolUse { id, name, input });
+        }
+    }
+}
+
+fn push_agent_output_block(
+    block: OutputContentBlock,
+    events: &mut Vec<AssistantEvent>,
+    pending_tool: &mut Option<(String, String, String)>,
+) {
+    match block {
+        OutputContentBlock::Text { text } => {
+            if !text.is_empty() {
+                events.push(AssistantEvent::TextDelta(text));
+            }
+        }
+        OutputContentBlock::ToolUse { id, name, input } => {
+            *pending_tool = Some((id, name, input.to_string()));
+        }
+    }
+}
+
+#[derive(Debug)]
+struct ScriptedAgentApiClient {
+    turns: Vec<Vec<ScriptedAgentEvent>>,
+    call_count: usize,
+}
+
+impl ScriptedAgentApiClient {
+    fn new(script: &str) -> Result<Self, String> {
+        let turns = serde_json::from_str(script).map_err(|error| error.to_string())?;
+        Ok(Self {
+            turns,
+            call_count: 0,
+        })
+    }
+}
+
+impl ApiClient for ScriptedAgentApiClient {
+    fn stream(&mut self, _request: ApiRequest) -> Result<Vec<AssistantEvent>, RuntimeError> {
+        if self.call_count >= self.turns.len() {
+            return Err(RuntimeError::new("scripted agent client exhausted"));
+        }
+        let events = self.turns[self.call_count]
+            .iter()
+            .map(ScriptedAgentEvent::to_runtime_event)
+            .chain(std::iter::once(AssistantEvent::MessageStop))
+            .collect();
+        self.call_count += 1;
+        Ok(events)
+    }
+}
+
+#[derive(Debug, Clone, Deserialize)]
+#[serde(tag = "type", rename_all = "snake_case")]
+enum ScriptedAgentEvent {
+    Text {
+        text: String,
+    },
+    ToolUse {
+        id: String,
+        name: String,
+        input: Value,
+    },
+}
+
+impl ScriptedAgentEvent {
+    fn to_runtime_event(&self) -> AssistantEvent {
+        match self {
+            Self::Text { text } => AssistantEvent::TextDelta(text.clone()),
+            Self::ToolUse { id, name, input } => AssistantEvent::ToolUse {
+                id: id.clone(),
+                name: name.clone(),
+                input: input.to_string(),
+            },
+        }
+    }
+}
+
+fn extract_message_text(message: &ConversationMessage) -> Option<String> {
+    let text = message
+        .blocks
+        .iter()
+        .filter_map(|block| match block {
+            ContentBlock::Text { text } => Some(text.as_str()),
+            _ => None,
+        })
+        .collect::<String>();
+    (!text.is_empty()).then_some(text)
+}
+
+fn extract_agent_tool_result(message: &ConversationMessage) -> Option<AgentToolResult> {
+    message.blocks.iter().find_map(|block| match block {
+        ContentBlock::ToolResult {
+            tool_name,
+            output,
+            is_error,
+            ..
+        } => Some(AgentToolResult {
+            tool_name: tool_name.clone(),
+            output: output.clone(),
+            is_error: *is_error,
+        }),
+        _ => None,
+    })
+}
+
 #[allow(clippy::needless_pass_by_value)]
 fn execute_tool_search(input: ToolSearchInput) -> ToolSearchOutput {
     let deferred = deferred_tool_specs();
@@ -2763,12 +3251,28 @@ mod tests {
     }
 
     #[test]
-    fn agent_persists_handoff_metadata() {
+    fn agent_executes_child_conversation_and_persists_results() {
         let _guard = env_lock()
             .lock()
             .unwrap_or_else(std::sync::PoisonError::into_inner);
         let dir = temp_path("agent-store");
         std::env::set_var("CLAWD_AGENT_STORE", &dir);
+        std::env::set_var(
+            "CLAWD_AGENT_TEST_SCRIPT",
+            serde_json::to_string(&vec![
+                vec![json!({
+                    "type": "tool_use",
+                    "id": "tool-1",
+                    "name": "StructuredOutput",
+                    "input": {"ok": true, "items": [1, 2, 3]}
+                })],
+                vec![json!({
+                    "type": "text",
+                    "text": "Child agent completed successfully."
+                })],
+            ])
+            .expect("script json"),
+        );
 
         let result = execute_tool(
             "Agent",
@@ -2780,22 +3284,35 @@ mod tests {
             }),
         )
         .expect("Agent should succeed");
+        std::env::remove_var("CLAWD_AGENT_TEST_SCRIPT");
         std::env::remove_var("CLAWD_AGENT_STORE");
 
         let output: serde_json::Value = serde_json::from_str(&result).expect("valid json");
         assert_eq!(output["name"], "ship-audit");
         assert_eq!(output["subagentType"], "Explore");
-        assert_eq!(output["status"], "queued");
-        assert!(output["createdAt"].as_str().is_some());
+        assert_eq!(output["status"], "completed");
+        assert_eq!(output["depth"], 0);
+        assert_eq!(output["maxDepth"], 3);
+        assert_eq!(output["result"], "Child agent completed successfully.");
+        assert_eq!(output["toolResults"][0]["toolName"], "StructuredOutput");
+        assert_eq!(output["toolResults"][0]["isError"], false);
         let manifest_file = output["manifestFile"].as_str().expect("manifest file");
         let output_file = output["outputFile"].as_str().expect("output file");
         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");
-        assert!(contents.contains("Audit the branch"));
-        assert!(contents.contains("Check tests and outstanding work."));
+        assert!(contents.contains("Child agent completed successfully."));
+        assert!(contents.contains("StructuredOutput [ok]"));
         assert!(manifest_contents.contains("\"subagentType\": \"Explore\""));
 
+        std::env::set_var(
+            "CLAWD_AGENT_TEST_SCRIPT",
+            serde_json::to_string(&vec![vec![json!({
+                "type": "text",
+                "text": "Normalized alias check."
+            })]])
+            .expect("script json"),
+        );
         let normalized = execute_tool(
             "Agent",
             &json!({
@@ -2805,10 +3322,19 @@ mod tests {
             }),
         )
         .expect("Agent should normalize built-in aliases");
+        std::env::remove_var("CLAWD_AGENT_TEST_SCRIPT");
         let normalized_output: serde_json::Value =
             serde_json::from_str(&normalized).expect("valid json");
         assert_eq!(normalized_output["subagentType"], "Explore");
 
+        std::env::set_var(
+            "CLAWD_AGENT_TEST_SCRIPT",
+            serde_json::to_string(&vec![vec![json!({
+                "type": "text",
+                "text": "Name normalization check."
+            })]])
+            .expect("script json"),
+        );
         let named = execute_tool(
             "Agent",
             &json!({
@@ -2818,13 +3344,14 @@ mod tests {
             }),
         )
         .expect("Agent should normalize explicit names");
+        std::env::remove_var("CLAWD_AGENT_TEST_SCRIPT");
         let named_output: serde_json::Value = serde_json::from_str(&named).expect("valid json");
         assert_eq!(named_output["name"], "ship-audit");
         let _ = std::fs::remove_dir_all(dir);
     }
 
     #[test]
-    fn agent_rejects_blank_required_fields() {
+    fn agent_rejects_blank_required_fields_and_enforces_max_depth() {
         let missing_description = execute_tool(
             "Agent",
             &json!({
@@ -2844,6 +3371,22 @@ mod tests {
         )
         .expect_err("blank prompt should fail");
         assert!(missing_prompt.contains("prompt must not be empty"));
+
+        let _guard = env_lock()
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner);
+        std::env::set_var("CLAWD_AGENT_DEPTH", "1");
+        let depth_error = execute_tool(
+            "Agent",
+            &json!({
+                "description": "Nested agent",
+                "prompt": "Do nested work.",
+                "max_depth": 1
+            }),
+        )
+        .expect_err("max depth should fail");
+        std::env::remove_var("CLAWD_AGENT_DEPTH");
+        assert!(depth_error.contains("max_depth exceeded"));
     }
 
     #[test]