feat(coding-agent): added hidden title role for prioritized title model selection

- Added a new built-in `title` model role with `hidden` metadata and updated role definitions and schema.
- Updated title generation to resolve models in `title`, `commit`, then `smol` order and added test coverage for that precedence.
- Filtered hidden roles from selector badges and documented the new built-in role in model/settings docs.

docs/models.md

@@ -417,7 +417,7 @@ Resolution precedence for exact selectors:
 
 Supported model roles:
 
-- `default`, `smol`, `slow`, `vision`, `plan`, `designer`, `commit`, `task`
+- `default`, `smol`, `slow`, `vision`, `plan`, `designer`, `commit`, `title`, `task`
 
 Role aliases like `pi/smol` expand through `settings.modelRoles`. Each role value can also append a thinking selector such as `:minimal`, `:low`, `:medium`, or `:high`.
 

docs/settings.md

@@ -299,7 +299,7 @@ enabledModels:
 
 | Key | Type | Default | Notes |
 |---|---|---|---|
-| `modelRoles` | record | `{}` | Map of role name -> model id. Built-in roles: `default`, `smol`, `slow`, `vision`, `plan`, `designer`, `commit`, `task`. Per-role env/flags: `--model`/`--smol`/`--slow`/`--plan`. |
+| `modelRoles` | record | `{}` | Map of role name -> model id. Built-in roles: `default`, `smol`, `slow`, `vision`, `plan`, `designer`, `commit`, `title`, `task`. Per-role env/flags: `--model`/`--smol`/`--slow`/`--plan`. |
 | `modelTags` | record | `{}` | Custom role/tag metadata; can introduce additional roles. |
 | `modelProviderOrder` | array | `[]` | Preferred provider order when a model id is ambiguous. |
 | `cycleOrder` | array | `["smol","default","slow"]` | Roles cycled by the model switcher. |

packages/coding-agent/src/config/model-roles.ts

@@ -5,12 +5,14 @@
 import { isValidThemeColor, type ThemeColor } from "../modes/theme/theme";
 import type { Settings } from "./settings";
 
-export type ModelRole = "default" | "smol" | "slow" | "vision" | "plan" | "designer" | "commit" | "task";
+export type ModelRole = "default" | "smol" | "slow" | "vision" | "plan" | "designer" | "commit" | "title" | "task";
 
 export interface ModelRoleInfo {
 	tag?: string;
 	name: string;
 	color?: ThemeColor;
+	/** If true, the role is functional but not shown in the model selector UI. */
+	hidden?: boolean;
 }
 
 export const MODEL_ROLES: Record<ModelRole, ModelRoleInfo> = {
@@ -21,12 +23,22 @@ export const MODEL_ROLES: Record<ModelRole, ModelRoleInfo> = {
 	plan: { tag: "PLAN", name: "Architect", color: "muted" },
 	designer: { tag: "DESIGNER", name: "Designer", color: "muted" },
 	commit: { tag: "COMMIT", name: "Commit", color: "dim" },
+	title: { tag: "TITLE", name: "Title", color: "dim", hidden: true },
 	task: { tag: "TASK", name: "Subtask", color: "muted" },
 };
 
-export const MODEL_ROLE_IDS: ModelRole[] = ["default", "smol", "slow", "vision", "plan", "designer", "commit", "task"];
+export const MODEL_ROLE_IDS: ModelRole[] = [
+	"default",
+	"smol",
+	"slow",
+	"vision",
+	"plan",
+	"designer",
+	"commit",
+	"title",
+	"task",
+];
 
-/** Alias for ModelRoleInfo - used for both built-in and custom roles */
 export type RoleInfo = ModelRoleInfo;
 
 /**
@@ -37,7 +49,7 @@ export type RoleInfo = ModelRoleInfo;
  * entries across settings.
  */
 export function getKnownRoleIds(settings: Settings): string[] {
-	const roles = [...MODEL_ROLE_IDS] as string[];
+	const roles = MODEL_ROLE_IDS.filter(role => !MODEL_ROLES[role as ModelRole]?.hidden) as string[];
 	const seen = new Set<string>(roles);
 	const addRole = (role: string) => {
 		if (seen.has(role)) return;
@@ -65,6 +77,7 @@ export function getRoleInfo(role: string, settings: Settings): RoleInfo {
 			tag: builtIn?.tag,
 			name: configured.name || builtIn?.name || role,
 			color: configured.color && isValidThemeColor(configured.color) ? configured.color : builtIn?.color,
+			hidden: configured.hidden ?? builtIn?.hidden,
 		};
 	}
 

packages/coding-agent/src/config/settings-schema.ts

@@ -258,6 +258,8 @@ type SettingDef =
 export interface ModelTagDef {
 	name: string;
 	color?: string;
+	/** If true, the role is functional but not shown in the model selector UI. */
+	hidden?: boolean;
 }
 
 export interface ModelTagsSettings {

packages/coding-agent/src/modes/components/model-selector.ts

@@ -936,7 +936,8 @@ export class ModelSelectorComponent extends Container {
 			// Build role badges. Solid badges are configured; outlined badges are auto-selected defaults.
 			const roleBadgeTokens: string[] = [];
 			for (const role of MODEL_ROLE_IDS) {
-				const { tag, color } = getRoleInfo(role, this.#settings);
+				const { tag, color, hidden } = getRoleInfo(role, this.#settings);
+				if (hidden) continue;
 				const assigned = this.#roles[role];
 				if (!tag || !assigned || !modelsAreEqual(assigned.model, item.model)) continue;
 

packages/coding-agent/src/utils/title-generator.ts

@@ -73,7 +73,7 @@ function getTitleModel(registry: ModelRegistry, settings: Settings, currentModel
 	const availableModels = registry.getAvailable();
 	if (availableModels.length === 0) return undefined;
 
-	const titleModel = resolveRoleSelection(["commit", "smol"], settings, availableModels, registry)?.model;
+	const titleModel = resolveRoleSelection(["title", "commit", "smol"], settings, availableModels, registry)?.model;
 	if (titleModel) return titleModel;
 
 	if (currentModel) return currentModel;

packages/coding-agent/test/title-generator.test.ts

@@ -373,4 +373,87 @@ describe("title generator", () => {
 		expect(request?.systemPrompt?.[0]).toBe(customPrompt);
 		expect(request?.systemPrompt?.[1]).toContain("<title>");
 	});
+
+	it("resolves the model roles in precedence order: title -> commit -> smol", async () => {
+		const titleModel = getModelOrThrow("claude-haiku-4-5");
+		const commitModel = getModelOrThrow("claude-sonnet-4-5");
+		const smolModel = getModelOrThrow("claude-opus-4-8");
+
+		const mockComplete = vi.spyOn(ai, "completeSimple").mockResolvedValue({
+			stopReason: "stop",
+			content: [{ type: "text", text: "<title>Test Title</title>" }],
+		} as never);
+
+		// Case 1: All three roles configured. 'title' should be used.
+		let currentSettings = {
+			get(path: string) {
+				if (path === "providers.tinyModel") return "online";
+				return undefined;
+			},
+			getModelRole(role: string) {
+				if (role === "title") return `${titleModel.provider}/${titleModel.id}`;
+				if (role === "commit") return `${commitModel.provider}/${commitModel.id}`;
+				if (role === "smol") return `${smolModel.provider}/${smolModel.id}`;
+				return undefined;
+			},
+			getStorage() {
+				return undefined;
+			},
+		} as never;
+
+		const registry = {
+			getAvailable: () => [titleModel, commitModel, smolModel],
+			getApiKey: async () => "test-key",
+			getApiKeyForProvider: async () => "test-key",
+			authStorage: { rotateSessionCredential: async () => false },
+			resolver: () => async () => "test-key",
+		} as never;
+
+		await generateSessionTitle("Some message", registry, currentSettings);
+		expect(mockComplete).toHaveBeenCalled();
+		expect(mockComplete.mock.calls[0]?.[0]).toBe(titleModel);
+
+		mockComplete.mockClear();
+
+		// Case 2: 'title' role not configured, 'commit' and 'smol' configured. 'commit' should be used.
+		currentSettings = {
+			get(path: string) {
+				if (path === "providers.tinyModel") return "online";
+				return undefined;
+			},
+			getModelRole(role: string) {
+				if (role === "commit") return `${commitModel.provider}/${commitModel.id}`;
+				if (role === "smol") return `${smolModel.provider}/${smolModel.id}`;
+				return undefined;
+			},
+			getStorage() {
+				return undefined;
+			},
+		} as never;
+
+		await generateSessionTitle("Some message", registry, currentSettings);
+		expect(mockComplete).toHaveBeenCalled();
+		expect(mockComplete.mock.calls[0]?.[0]).toBe(commitModel);
+
+		mockComplete.mockClear();
+
+		// Case 3: Only 'smol' role configured. 'smol' should be used.
+		currentSettings = {
+			get(path: string) {
+				if (path === "providers.tinyModel") return "online";
+				return undefined;
+			},
+			getModelRole(role: string) {
+				if (role === "smol") return `${smolModel.provider}/${smolModel.id}`;
+				return undefined;
+			},
+			getStorage() {
+				return undefined;
+			},
+		} as never;
+
+		await generateSessionTitle("Some message", registry, currentSettings);
+		expect(mockComplete).toHaveBeenCalled();
+		expect(mockComplete.mock.calls[0]?.[0]).toBe(smolModel);
+	});
 });