feat: b5-tool-timeout — batch 5 upstream parity

rust/crates/runtime/src/config.rs

@@ -58,6 +58,7 @@ pub struct RuntimeFeatureConfig {
     mcp: McpConfigCollection,
     oauth: Option<OAuthConfig>,
     model: Option<String>,
+    aliases: BTreeMap<String, String>,
     permission_mode: Option<ResolvedPermissionMode>,
     permission_rules: RuntimePermissionRuleConfig,
     sandbox: SandboxConfig,
@@ -290,6 +291,7 @@ impl ConfigLoader {
             },
             oauth: parse_optional_oauth_config(&merged_value, "merged settings.oauth")?,
             model: parse_optional_model(&merged_value),
+            aliases: parse_optional_aliases(&merged_value)?,
             permission_mode: parse_optional_permission_mode(&merged_value)?,
             permission_rules: parse_optional_permission_rules(&merged_value)?,
             sandbox: parse_optional_sandbox_config(&merged_value)?,
@@ -364,6 +366,11 @@ impl RuntimeConfig {
         self.feature_config.model.as_deref()
     }
 
+    #[must_use]
+    pub fn aliases(&self) -> &BTreeMap<String, String> {
+        &self.feature_config.aliases
+    }
+
     #[must_use]
     pub fn permission_mode(&self) -> Option<ResolvedPermissionMode> {
         self.feature_config.permission_mode
@@ -423,6 +430,11 @@ impl RuntimeFeatureConfig {
         self.model.as_deref()
     }
 
+    #[must_use]
+    pub fn aliases(&self) -> &BTreeMap<String, String> {
+        &self.aliases
+    }
+
     #[must_use]
     pub fn permission_mode(&self) -> Option<ResolvedPermissionMode> {
         self.permission_mode
@@ -680,6 +692,13 @@ fn parse_optional_model(root: &JsonValue) -> Option<String> {
         .map(ToOwned::to_owned)
 }
 
+fn parse_optional_aliases(root: &JsonValue) -> Result<BTreeMap<String, String>, ConfigError> {
+    let Some(object) = root.as_object() else {
+        return Ok(BTreeMap::new());
+    };
+    Ok(optional_string_map(object, "aliases", "merged settings")?.unwrap_or_default())
+}
+
 fn parse_optional_hooks_config(root: &JsonValue) -> Result<RuntimeHookConfig, ConfigError> {
     let Some(object) = root.as_object() else {
         return Ok(RuntimeHookConfig::default());
@@ -1613,6 +1632,49 @@ mod tests {
         fs::remove_dir_all(root).expect("cleanup temp dir");
     }
 
+    #[test]
+    fn parses_user_defined_model_aliases_from_settings() {
+        // given
+        let root = temp_dir();
+        let cwd = root.join("project");
+        let home = root.join("home").join(".claw");
+        fs::create_dir_all(cwd.join(".claw")).expect("project config dir");
+        fs::create_dir_all(&home).expect("home config dir");
+
+        fs::write(
+            home.join("settings.json"),
+            r#"{"aliases":{"fast":"claude-haiku-4-5-20251213","smart":"claude-opus-4-6"}}"#,
+        )
+        .expect("write user settings");
+        fs::write(
+            cwd.join(".claw").join("settings.local.json"),
+            r#"{"aliases":{"smart":"claude-sonnet-4-6","cheap":"grok-3-mini"}}"#,
+        )
+        .expect("write local settings");
+
+        // when
+        let loaded = ConfigLoader::new(&cwd, &home)
+            .load()
+            .expect("config should load");
+
+        // then
+        let aliases = loaded.aliases();
+        assert_eq!(
+            aliases.get("fast").map(String::as_str),
+            Some("claude-haiku-4-5-20251213")
+        );
+        assert_eq!(
+            aliases.get("smart").map(String::as_str),
+            Some("claude-sonnet-4-6")
+        );
+        assert_eq!(
+            aliases.get("cheap").map(String::as_str),
+            Some("grok-3-mini")
+        );
+
+        fs::remove_dir_all(root).expect("cleanup temp dir");
+    }
+
     #[test]
     fn empty_settings_file_loads_defaults() {
         // given