feat(git): add model selection for commit message generation

.gitignore

@@ -27,6 +27,10 @@ dist-ssr
 CodexMonitor.zip
 .codex-worktrees/
 .codexmonitor/
+.agent/
+.agents/
+.claude/
+.cursor/
 public/assets/material-icons/
 
 # Nix

src-tauri/src/bin/codex_monitor_daemon.rs

@@ -1231,7 +1231,11 @@ impl DaemonState {
         codex_aux_core::codex_doctor_core(&self.app_settings, codex_bin, codex_args).await
     }
 
-    async fn generate_commit_message(&self, workspace_id: String) -> Result<String, String> {
+    async fn generate_commit_message(
+        &self,
+        workspace_id: String,
+        commit_message_model_id: Option<String>,
+    ) -> Result<String, String> {
         let repo_root = git_ui_core::resolve_repo_root_for_workspace_core(
             &self.workspaces,
             workspace_id.clone(),
@@ -1247,6 +1251,7 @@ impl DaemonState {
             workspace_id,
             &diff,
             &commit_message_prompt,
+            commit_message_model_id.as_deref(),
             |workspace_id, thread_id| {
                 emit_background_thread_hide(&self.event_sink, workspace_id, thread_id);
             },

src-tauri/src/bin/codex_monitor_daemon/rpc/git.rs

@@ -366,7 +366,11 @@ pub(super) async fn try_handle(
                 Ok(value) => value,
                 Err(err) => return Some(Err(err)),
             };
-            let message = match state.generate_commit_message(workspace_id).await {
+            let commit_message_model_id = parse_optional_string(params, "commitMessageModelId");
+            let message = match state
+                .generate_commit_message(workspace_id, commit_message_model_id)
+                .await
+            {
                 Ok(value) => value,
                 Err(err) => return Some(Err(err)),
             };

src-tauri/src/codex/mod.rs

@@ -875,6 +875,7 @@ pub(crate) async fn get_config_model(
 #[tauri::command]
 pub(crate) async fn generate_commit_message(
     workspace_id: String,
+    commit_message_model_id: Option<String>,
     state: State<'_, AppState>,
     app: AppHandle,
 ) -> Result<String, String> {
@@ -883,7 +884,10 @@ pub(crate) async fn generate_commit_message(
             &*state,
             app,
             "generate_commit_message",
-            json!({ "workspaceId": workspace_id }),
+            json!({
+                "workspaceId": workspace_id,
+                "commitMessageModelId": commit_message_model_id,
+            }),
         )
         .await?;
         return serde_json::from_value(value).map_err(|err| err.to_string());
@@ -900,6 +904,7 @@ pub(crate) async fn generate_commit_message(
         workspace_id,
         &diff,
         &commit_message_prompt,
+        commit_message_model_id.as_deref(),
         |workspace_id, thread_id| {
             let _ = app.emit(
                 "app-server-event",

src-tauri/src/shared/codex_aux_core.rs

@@ -395,6 +395,7 @@ pub(crate) async fn run_background_prompt_core<F>(
     sessions: &Mutex<HashMap<String, Arc<WorkspaceSession>>>,
     workspace_id: String,
     prompt: String,
+    model: Option<&str>,
     on_hide_thread: F,
     timeout_error: &str,
     turn_error_fallback: &str,
@@ -452,13 +453,16 @@ where
         callbacks.insert(thread_id.clone(), tx);
     }
 
-    let turn_params = json!({
+    let mut turn_params = json!({
         "threadId": thread_id,
         "input": [{ "type": "text", "text": prompt }],
         "cwd": session.entry.path,
         "approvalPolicy": "never",
         "sandboxPolicy": { "type": "readOnly" },
     });
+    if let Some(model_id) = model {
+        turn_params["model"] = json!(model_id);
+    }
     let turn_result = session.send_request("turn/start", turn_params).await;
     let turn_result = match turn_result {
         Ok(result) => result,
@@ -545,6 +549,7 @@ pub(crate) async fn generate_commit_message_core<F>(
     workspace_id: String,
     diff: &str,
     template: &str,
+    model: Option<&str>,
     on_hide_thread: F,
 ) -> Result<String, String>
 where
@@ -555,6 +560,7 @@ where
         sessions,
         workspace_id,
         prompt,
+        model,
         on_hide_thread,
         "Timeout waiting for commit message generation",
         "Unknown error during commit message generation",
@@ -581,6 +587,7 @@ where
         sessions,
         workspace_id,
         metadata_prompt,
+        None,
         on_hide_thread,
         "Timeout waiting for metadata generation",
         "Unknown error during metadata generation",
@@ -609,6 +616,7 @@ where
         sessions,
         workspace_id,
         prompt,
+        None,
         on_hide_thread,
         "Timeout waiting for agent configuration generation",
         "Unknown error during agent configuration generation",

src-tauri/src/types.rs

@@ -533,6 +533,8 @@ pub(crate) struct AppSettings {
         rename = "commitMessagePrompt"
     )]
     pub(crate) commit_message_prompt: String,
+    #[serde(default, rename = "commitMessageModelId")]
+    pub(crate) commit_message_model_id: Option<String>,
     #[serde(
         default = "default_system_notifications_enabled",
         rename = "systemNotificationsEnabled"
@@ -1140,6 +1142,7 @@ impl Default for AppSettings {
             preload_git_diffs: default_preload_git_diffs(),
             git_diff_ignore_whitespace_changes: default_git_diff_ignore_whitespace_changes(),
             commit_message_prompt: default_commit_message_prompt(),
+            commit_message_model_id: None,
             collaboration_modes_enabled: true,
             steer_enabled: true,
             pause_queued_messages_when_response_required:

src/App.tsx

@@ -107,6 +107,7 @@ import { useWorkspaceLaunchScript } from "@app/hooks/useWorkspaceLaunchScript";
 import { useWorkspaceLaunchScripts } from "@app/hooks/useWorkspaceLaunchScripts";
 import { useWorktreeSetupScript } from "@app/hooks/useWorktreeSetupScript";
 import { useGitCommitController } from "@app/hooks/useGitCommitController";
+import { effectiveCommitMessageModelId } from "@/features/git/utils/commitMessageModelSelection";
 import { WorkspaceHome } from "@/features/workspaces/components/WorkspaceHome";
 import { MobileServerSetupWizard } from "@/features/mobile/components/MobileServerSetupWizard";
 import { useMobileServerSetup } from "@/features/mobile/hooks/useMobileServerSetup";
@@ -446,6 +447,10 @@ function MainApp() {
     setSelectedCodexArgsOverride,
     persistThreadCodexParams,
   });
+  const commitMessageModelId = useMemo(
+    () => effectiveCommitMessageModelId(models, appSettings.commitMessageModelId),
+    [models, appSettings.commitMessageModelId],
+  );
 
   const composerShortcuts = {
     modelShortcut: appSettings.composerModelShortcut,
@@ -1522,6 +1527,7 @@ function MainApp() {
     activeWorkspace,
     activeWorkspaceId,
     activeWorkspaceIdRef,
+    commitMessageModelId,
     gitStatus,
     refreshGitStatus,
     refreshGitLog,

src/features/app/hooks/useGitCommitController.ts

@@ -18,6 +18,7 @@ type GitCommitControllerOptions = {
   activeWorkspace: WorkspaceInfo | null;
   activeWorkspaceId: string | null;
   activeWorkspaceIdRef: RefObject<string | null>;
+  commitMessageModelId: string | null;
   gitStatus: GitStatusState;
   refreshGitStatus: () => void;
   refreshGitLog?: () => void;
@@ -53,6 +54,7 @@ export function useGitCommitController({
   activeWorkspace,
   activeWorkspaceId,
   activeWorkspaceIdRef,
+  commitMessageModelId,
   gitStatus,
   refreshGitStatus,
   refreshGitLog,
@@ -100,7 +102,7 @@ export function useGitCommitController({
     setCommitMessageLoading(true);
     setCommitMessageError(null);
     try {
-      const message = await generateCommitMessage(workspaceId);
+      const message = await generateCommitMessage(workspaceId, commitMessageModelId);
       if (!shouldApplyCommitMessage(activeWorkspaceIdRef.current, workspaceId)) {
         return;
       }
@@ -117,7 +119,7 @@ export function useGitCommitController({
         setCommitMessageLoading(false);
       }
     }
-  }, [activeWorkspace, commitMessageLoading, activeWorkspaceIdRef]);
+  }, [activeWorkspace, commitMessageLoading, activeWorkspaceIdRef, commitMessageModelId]);
 
   useEffect(() => {
     setCommitMessage("");

src/features/git/utils/commitMessageModelSelection.test.ts

@@ -0,0 +1,42 @@
+import { describe, expect, it } from "vitest";
+import type { ModelOption } from "@/types";
+import { effectiveCommitMessageModelId } from "./commitMessageModelSelection";
+
+const MODELS: ModelOption[] = [
+  {
+    id: "m-1",
+    model: "gpt-5.1",
+    displayName: "GPT-5.1",
+    description: "",
+    supportedReasoningEfforts: [],
+    defaultReasoningEffort: null,
+    isDefault: false,
+  },
+  {
+    id: "m-2",
+    model: "gpt-5.2",
+    displayName: "GPT-5.2",
+    description: "",
+    supportedReasoningEfforts: [],
+    defaultReasoningEffort: null,
+    isDefault: true,
+  },
+];
+
+describe("effectiveCommitMessageModelId", () => {
+  it("passes through null when no model is saved", () => {
+    expect(effectiveCommitMessageModelId(MODELS, null)).toBeNull();
+  });
+
+  it("returns the saved model when it exists in the workspace", () => {
+    expect(effectiveCommitMessageModelId(MODELS, "gpt-5.1")).toBe("gpt-5.1");
+  });
+
+  it("falls back to null when saved model is unavailable in the workspace", () => {
+    expect(effectiveCommitMessageModelId(MODELS, "gpt-4.1")).toBeNull();
+  });
+
+  it("falls back to null when no models are available", () => {
+    expect(effectiveCommitMessageModelId([], "gpt-5.1")).toBeNull();
+  });
+});

src/features/git/utils/commitMessageModelSelection.ts

@@ -0,0 +1,15 @@
+import type { ModelOption } from "@/types";
+
+/**
+ * Returns the saved commit-message model ID when available for the active
+ * workspace, or `null` to let the backend fall back to the workspace default.
+ *
+ * This is a pure runtime guard — it never mutates the persisted setting.
+ */
+export function effectiveCommitMessageModelId(
+  models: ModelOption[],
+  savedModelId: string | null,
+): string | null {
+  if (savedModelId == null) return null;
+  return models.some((m) => m.model === savedModelId) ? savedModelId : null;
+}

src/features/models/utils/modelListResponse.test.ts

@@ -0,0 +1,98 @@
+import { describe, expect, it } from "vitest";
+import { formatModelSlug, parseModelListResponse } from "./modelListResponse";
+
+describe("formatModelSlug", () => {
+  it("capitalizes plain segments", () => {
+    expect(formatModelSlug("codex-mini")).toBe("Codex-Mini");
+  });
+
+  it("uppercases known acronyms", () => {
+    expect(formatModelSlug("gpt-5.3-codex")).toBe("GPT-5.3-Codex");
+  });
+
+  it("leaves version-like segments unchanged", () => {
+    expect(formatModelSlug("gpt-5.1-codex-max")).toBe("GPT-5.1-Codex-Max");
+  });
+
+  it("handles a version-only slug", () => {
+    expect(formatModelSlug("gpt-5.2")).toBe("GPT-5.2");
+  });
+  it("is case-insensitive for acronym detection", () => {
+    expect(formatModelSlug("GPT-5.3-codex")).toBe("GPT-5.3-Codex");
+    expect(formatModelSlug("Gpt-5.3-codex")).toBe("GPT-5.3-Codex");
+  });
+
+  it("returns empty string for non-string input", () => {
+    expect(formatModelSlug(null)).toBe("");
+    expect(formatModelSlug(undefined)).toBe("");
+    expect(formatModelSlug(42)).toBe("");
+  });
+
+  it("returns empty string for blank strings", () => {
+    expect(formatModelSlug("")).toBe("");
+    expect(formatModelSlug("   ")).toBe("");
+  });
+
+  it("handles a single segment", () => {
+    expect(formatModelSlug("codex")).toBe("Codex");
+    expect(formatModelSlug("gpt")).toBe("GPT");
+  });
+});
+
+describe("parseModelListResponse", () => {
+  it("uses displayName when present", () => {
+    const response = {
+      result: {
+        data: [
+          { id: "m1", model: "gpt-5.3-codex-spark", displayName: "GPT-5.3-Codex-Spark" },
+        ],
+      },
+    };
+    const [model] = parseModelListResponse(response);
+    expect(model.displayName).toBe("GPT-5.3-Codex-Spark");
+  });
+
+  it("formats the slug when displayName is missing", () => {
+    const response = {
+      result: {
+        data: [{ id: "m1", model: "gpt-5.3-codex" }],
+      },
+    };
+    const [model] = parseModelListResponse(response);
+    expect(model.displayName).toBe("GPT-5.3-Codex");
+  });
+
+  it("formats the slug when displayName is an empty string", () => {
+    const response = {
+      result: {
+        data: [{ id: "m1", model: "gpt-5.1-codex-mini", displayName: "" }],
+      },
+    };
+    const [model] = parseModelListResponse(response);
+    expect(model.displayName).toBe("GPT-5.1-Codex-Mini");
+  });
+
+  it("formats the slug when displayName equals the model slug", () => {
+    const response = {
+      result: {
+        data: [{ id: "m1", model: "gpt-5.3-codex", displayName: "gpt-5.3-codex" }],
+      },
+    };
+    const [model] = parseModelListResponse(response);
+    expect(model.displayName).toBe("GPT-5.3-Codex");
+  });
+
+  it("preserves displayName when it differs from the slug", () => {
+    const response = {
+      result: {
+        data: [
+          { id: "m1", model: "gpt-5.3-codex-spark", displayName: "GPT-5.3-Codex-Spark" },
+          { id: "m2", model: "gpt-5.2-codex", displayName: "gpt-5.2-codex" },
+        ],
+      },
+    };
+    const models = parseModelListResponse(response);
+    expect(models[0].displayName).toBe("GPT-5.3-Codex-Spark");
+    expect(models[1].displayName).toBe("GPT-5.2-Codex");
+  });
+});