FN-6218: restore pi upgrade compatibility

Restore Pi-upgraded workspaces to keep Fusion resources accessible and recover title generation when configured models go stale.

- Mark read-only Fusion/Pi provider settings views as project-trusted so extension loading keeps working after Pi upgrades.
- Retry task title summarization with automatic model resolution when the configured provider model is missing from the Pi registry.
- Cover provider settings trust behavior and stale summarizer fallback paths with regression tests.
- Document the read-only settings trust contract and add a patch changeset.

Files changed:
 .changeset/fn-6218-pi-upgrade-regressions.md       |   5 +
 docs/settings-reference.md                         |   2 +
 docs/task-management.md                            |   2 +
 .../commands/__tests__/provider-settings.test.ts   |  16 ++++
 packages/cli/src/commands/provider-settings.ts     |   5 +
 packages/core/src/__tests__/ai-summarize.test.ts   | 102 +++++++++++++++++++++
 packages/core/src/ai-summarize.ts                  |  85 ++++++++++++-----
 .../src/__tests__/pi-create-fn-agent.test.ts       |  32 +++++++
 packages/engine/src/pi.ts                          |   7 +-
 9 files changed, 233 insertions(+), 23 deletions(-)

Fusion-Task-Id: FN-6218

Fusion-Task-Lineage: 3d6aca32-a56a-43a0-a57b-8e6abc839ce9

.changeset/fn-6218-pi-upgrade-regressions.md

@@ -0,0 +1,5 @@
+---
+"@runfusion/fusion": patch
+---
+
+Fix pi 0.79 extension discovery compatibility and retry stale title-summarizer model ids with automatic model resolution.

docs/settings-reference.md

@@ -837,6 +837,8 @@ Project-scoped model lane used for task title auto-summarization, GitHub trackin
 5. Global `defaultProvider` + `defaultModelId`
 6. Automatic provider/model resolution
 
+If the configured title summarizer provider/model is stale and no longer exists in the pi model registry, title generation logs a warning with the stale id and retries once with automatic provider/model resolution. Other AI failures (auth, empty output, unavailable engine) still fail normally.
+
 > **Note:** Runtime fallback precedence logic is implemented in engine and dashboard routes. The hierarchies above reflect current runtime behavior.
 
 ---

docs/task-management.md

@@ -855,6 +855,8 @@ Users can apply presets at task creation; manual model selection can override th
 
 When `autoSummarizeTitles` is enabled and a task has a long untitled description, Fusion can auto-generate a concise title. This applies to tasks created from the dashboard/API as well as tasks created by agents and tooling flows (`fn_task_create`, delegated tasks, and triage-created child tasks). GitHub tracking now waits for the `createTask`-level summarizer (explicit or auto-attached from settings) to settle before filing, then uses that resulting title and falls back to deterministic description-derived title generation only when summarization is unavailable.
 
+If a configured title summarizer model is stale after a pi upgrade, Fusion logs a warning naming that provider/model and retries once with automatic model resolution before falling back to deterministic title generation. Genuine AI-service failures are not masked by this retry.
+
 ## Screenshots
 
 ### Board/task cards + quick entry

packages/cli/src/commands/__tests__/provider-settings.test.ts

@@ -46,6 +46,22 @@ describe("createReadOnlyProviderSettingsView", () => {
       shared: "fusion",
     });
     expect(view.getNpmCommand()).toEqual(["pnpm"]);
+    expect(view.isProjectTrusted()).toBe(true);
+  });
+
+  it("exposes project trust for pi package-manager discovery consumers", async () => {
+    const root = tempWorkspace("fusion-provider-settings-");
+    const cwd = join(root, "project");
+    const agentDir = join(root, "agent");
+    mkdirSync(agentDir, { recursive: true });
+
+    const view = createReadOnlyProviderSettingsView(cwd, agentDir);
+    const discoveryConsumer = {
+      resolve: vi.fn(async () => view.isProjectTrusted()),
+    };
+
+    await expect(discoveryConsumer.resolve()).resolves.toBe(true);
+    expect(typeof view.isProjectTrusted()).toBe("boolean");
   });
 
   it("returns empty project settings when .fusion/settings.json does not exist", () => {

packages/cli/src/commands/provider-settings.ts

@@ -5,6 +5,7 @@ export interface PackageManagerSettingsView {
   getGlobalSettings(): Record<string, unknown>;
   getProjectSettings(): Record<string, unknown>;
   getNpmCommand(): string[] | undefined;
+  isProjectTrusted(): boolean;
 }
 
 function siblingAgentDir(agentDir: string, siblingRoot: ".fusion" | ".pi"): string | undefined {
@@ -47,6 +48,10 @@ export function createReadOnlyProviderSettingsView(cwd: string, agentDir: string
     getNpmCommand: () => Array.isArray(mergedSettings.npmCommand)
       ? [...mergedSettings.npmCommand]
       : undefined,
+    // Pi's SettingsManager defaults projects to trusted. Fusion workspaces are
+    // user-owned, so preserve pre-upgrade behavior and keep project-scoped
+    // .fusion resources loadable through the read-only settings view.
+    isProjectTrusted: () => true,
   };
 }
 

packages/core/src/__tests__/ai-summarize.test.ts

@@ -255,6 +255,108 @@ describe("ai-summarize", () => {
       const title = await summarizeTitle("a".repeat(201), "/tmp");
       expect(title).toBe("Refactor merger title fallback");
     });
+
+    it("retries stale configured model ids with automatic resolution and logs the stale id", async () => {
+      const warnSpy = vi.spyOn(console, "warn").mockImplementation(() => {});
+      const createFnAgent = vi
+        .fn()
+        .mockRejectedValueOnce(new Error(
+          "Configured model fireworksai/accounts/fireworks/routers/kimi-k2p5-turbo (primary selection) "
+          + "was not found in the pi model registry.",
+        ))
+        .mockResolvedValueOnce({
+          session: {
+            prompt: vi.fn().mockResolvedValue(undefined),
+            dispose: vi.fn(),
+            state: {
+              messages: [{ role: "assistant", content: "Fix pi upgrade regressions" }],
+            },
+          },
+        });
+      getFnAgentMock.mockResolvedValue(createFnAgent);
+
+      const title = await summarizeTitle(
+        "a".repeat(201),
+        "/tmp",
+        "fireworksai",
+        "accounts/fireworks/routers/kimi-k2p5-turbo",
+      );
+
+      expect(title).toBe("Fix pi upgrade regressions");
+      expect(createFnAgent).toHaveBeenNthCalledWith(1, expect.objectContaining({
+        defaultProvider: "fireworksai",
+        defaultModelId: "accounts/fireworks/routers/kimi-k2p5-turbo",
+      }));
+      expect(createFnAgent).toHaveBeenNthCalledWith(2, expect.not.objectContaining({
+        defaultProvider: expect.any(String),
+        defaultModelId: expect.any(String),
+      }));
+      expect(warnSpy).toHaveBeenCalledWith(expect.stringContaining("fireworksai/accounts/fireworks/routers/kimi-k2p5-turbo"));
+      warnSpy.mockRestore();
+    });
+
+    it("keeps valid configured model ids on the primary summarizer path", async () => {
+      const createFnAgent = vi.fn().mockResolvedValue({
+        session: {
+          prompt: vi.fn().mockResolvedValue(undefined),
+          dispose: vi.fn(),
+          state: {
+            messages: [{ role: "assistant", content: "Keep configured model" }],
+          },
+        },
+      });
+      getFnAgentMock.mockResolvedValue(createFnAgent);
+
+      const title = await summarizeTitle("a".repeat(201), "/tmp", "anthropic", "claude-sonnet-4-5");
+
+      expect(title).toBe("Keep configured model");
+      expect(createFnAgent).toHaveBeenCalledTimes(1);
+      expect(createFnAgent).toHaveBeenCalledWith(expect.objectContaining({
+        defaultProvider: "anthropic",
+        defaultModelId: "claude-sonnet-4-5",
+      }));
+    });
+
+    it("returns null when stale-model automatic resolution also fails", async () => {
+      const warnSpy = vi.spyOn(console, "warn").mockImplementation(() => {});
+      const createFnAgent = vi
+        .fn()
+        .mockRejectedValueOnce(new Error(
+          "Configured model fireworksai/accounts/fireworks/routers/kimi-k2p5-turbo (primary selection) "
+          + "was not found in the pi model registry.",
+        ))
+        .mockRejectedValueOnce(new Error("No model selected"));
+      getFnAgentMock.mockResolvedValue(createFnAgent);
+
+      await expect(summarizeTitle(
+        "a".repeat(201),
+        "/tmp",
+        "fireworksai",
+        "accounts/fireworks/routers/kimi-k2p5-turbo",
+      )).resolves.toBeNull();
+      expect(createFnAgent).toHaveBeenCalledTimes(2);
+      expect(warnSpy).toHaveBeenCalledWith(expect.stringContaining("retrying with automatic model resolution"));
+      expect(warnSpy).toHaveBeenCalledWith(expect.stringContaining("Automatic title summarizer fallback"));
+      warnSpy.mockRestore();
+    });
+
+    it("does not mask genuine AI service errors", async () => {
+      getFnAgentMock.mockResolvedValue(() =>
+        Promise.resolve({
+          session: {
+            prompt: vi.fn().mockResolvedValue(undefined),
+            dispose: vi.fn(),
+            state: {
+              error: "authentication failed",
+              messages: [],
+            },
+          },
+        })
+      );
+
+      await expect(summarizeTitle("a".repeat(201), "/tmp", "anthropic", "claude-sonnet-4-5"))
+        .rejects.toThrow("AI session error: authentication failed");
+    });
   });
 
   describe("sanitizeTitle", () => {

packages/core/src/ai-summarize.ts

@@ -198,31 +198,22 @@ export function validateDescription(description: unknown): string {
 /** Debug flag for AI operations */
 const DEBUG = process.env.FUSION_DEBUG_AI === "true";
 
-/**
- * Summarize a task description into a concise title using AI.
- * @param description - The task description to summarize (must be 201-2000 chars)
- * @param rootDir - Project root directory for AI agent context
- * @param provider - Optional AI model provider (e.g., "anthropic")
- * @param modelId - Optional AI model ID (e.g., "claude-sonnet-4-5")
- * @returns The generated title (guaranteed ≤60 characters), or null if validation fails
- */
-export async function summarizeTitle(
+function isConfiguredModelNotFoundError(error: unknown): boolean {
+  const message = error instanceof Error ? error.message : String(error);
+  return /Configured model .+ was not found in the pi model registry/.test(message);
+}
+
+function formatConfiguredModel(provider?: string, modelId?: string): string {
+  return provider && modelId ? `${provider}/${modelId}` : "unknown configured model";
+}
+
+async function runTitleSummarizer(
+  createFnAgent: NonNullable<Awaited<ReturnType<typeof getFnAgent>>>,
   description: string,
   rootDir: string,
   provider?: string,
-  modelId?: string
-): Promise<string | null> {
-  // Validate description length first
-  if (description.length <= 200) {
-    return null; // Too short for summarization
-  }
-
-  const createFnAgent = await getFnAgent();
-  if (!createFnAgent) {
-    if (DEBUG) console.log("[ai-summarize] AI engine not available");
-    throw new AiServiceError("AI engine not available");
-  }
-
+  modelId?: string,
+): Promise<string> {
   const agentOptions: {
     cwd: string;
     systemPrompt: string;
@@ -324,6 +315,56 @@ export async function summarizeTitle(
   }
 }
 
+/**
+ * Summarize a task description into a concise title using AI.
+ * @param description - The task description to summarize (must be 201-2000 chars)
+ * @param rootDir - Project root directory for AI agent context
+ * @param provider - Optional AI model provider (e.g., "anthropic")
+ * @param modelId - Optional AI model ID (e.g., "claude-sonnet-4-5")
+ * @returns The generated title (guaranteed ≤60 characters), or null if validation fails
+ */
+export async function summarizeTitle(
+  description: string,
+  rootDir: string,
+  provider?: string,
+  modelId?: string
+): Promise<string | null> {
+  // Validate description length first
+  if (description.length <= 200) {
+    return null; // Too short for summarization
+  }
+
+  const createFnAgent = await getFnAgent();
+  if (!createFnAgent) {
+    if (DEBUG) console.log("[ai-summarize] AI engine not available");
+    throw new AiServiceError("AI engine not available");
+  }
+
+  try {
+    return await runTitleSummarizer(createFnAgent, description, rootDir, provider, modelId);
+  } catch (err) {
+    if (!provider || !modelId || !isConfiguredModelNotFoundError(err)) {
+      throw err;
+    }
+
+    const staleModel = formatConfiguredModel(provider, modelId);
+    console.warn(
+      `[ai-summarize] Configured title summarizer model ${staleModel} was not found in the pi model registry; `
+      + "retrying with automatic model resolution.",
+    );
+
+    try {
+      return await runTitleSummarizer(createFnAgent, description, rootDir);
+    } catch (retryError) {
+      const message = retryError instanceof Error ? retryError.message : String(retryError);
+      console.warn(
+        `[ai-summarize] Automatic title summarizer fallback after stale model ${staleModel} failed: ${message}`,
+      );
+      return null;
+    }
+  }
+}
+
 /** System prompt for AI merge commit summary generation. */
 export const MERGE_COMMIT_SUMMARIZE_SYSTEM_PROMPT = `You summarize merge commits for a task management system.
 

packages/engine/src/__tests__/pi-create-fn-agent.test.ts

@@ -30,6 +30,7 @@ const readFileSyncMock = vi.fn((_path?: any) => "{}");
 const realpathSyncNativeMock = vi.fn((path: PathLike) => String(path));
 const readCustomProvidersMock = vi.fn(() => []);
 const packageManagerCwdCapture = vi.fn();
+const packageManagerSettingsCapture = vi.fn();
 
 // Route async `exec` through the `execSync` mock so the promisify bridge works.
 // Use Symbol.for("nodejs.util.promisify.custom") directly to avoid async imports
@@ -107,10 +108,15 @@ vi.mock("@earendil-works/pi-coding-agent", () => ({
     }
   },
   DefaultPackageManager: class {
+    private readonly settingsManager: any;
+
     constructor(options: any) {
       packageManagerCwdCapture(options?.cwd);
+      packageManagerSettingsCapture(options?.settingsManager);
+      this.settingsManager = options?.settingsManager;
     }
     async resolve() {
+      this.settingsManager.isProjectTrusted();
       return packageManagerResolveMock();
     }
   },
@@ -1272,6 +1278,32 @@ describe("createFnAgent", () => {
     expect(createAgentSessionMock).toHaveBeenCalledTimes(1);
   });
 
+  it("exposes project trust on the read-only pi settings view", async () => {
+    const { createReadOnlyPiSettingsView } = await import("../pi.js");
+
+    const view = createReadOnlyPiSettingsView("/tmp", "/mock-agent-dir");
+
+    expect(() => view.isProjectTrusted()).not.toThrow();
+    expect(view.isProjectTrusted()).toBe(true);
+    expect(typeof view.isProjectTrusted()).toBe("boolean");
+  });
+
+  it("passes a project-trusted settings view through package-manager discovery", async () => {
+    const { createFnAgent } = await import("../pi.js");
+
+    await createFnAgent({
+      cwd: "/tmp",
+      systemPrompt: "test",
+      tools: "readonly",
+    });
+
+    const settingsView = packageManagerSettingsCapture.mock.calls.at(-1)?.[0];
+    expect(settingsView).toEqual(expect.objectContaining({ isProjectTrusted: expect.any(Function) }));
+    expect(settingsView.isProjectTrusted()).toBe(true);
+    expect(packageManagerResolveMock).toHaveBeenCalled();
+    expect(createAgentSessionMock).toHaveBeenCalledTimes(1);
+  });
+
   it("registers extension providers before resolving configured models", async () => {
     packageManagerResolveMock.mockResolvedValueOnce({
       extensions: [{ enabled: true, path: "/extensions/zai-provider" }],

packages/engine/src/pi.ts

@@ -1080,6 +1080,7 @@ interface PackageManagerSettingsView {
   getGlobalSettings(): Record<string, any>;
   getProjectSettings(): Record<string, any>;
   getNpmCommand(): string[] | undefined;
+  isProjectTrusted(): boolean;
 }
 
 function readJsonObject(path: string): Record<string, any> {
@@ -1258,7 +1259,7 @@ function siblingAgentDir(agentDir: string, siblingRoot: ".fusion" | ".pi"): stri
   return join(dirname(dirname(agentDir)), siblingRoot, "agent");
 }
 
-function createReadOnlyPiSettingsView(cwd: string, agentDir: string): PackageManagerSettingsView {
+export function createReadOnlyPiSettingsView(cwd: string, agentDir: string): PackageManagerSettingsView {
   const projectRoot = resolvePiExtensionProjectRoot(cwd);
   const fusionAgentDir = agentDir.includes(`${join(".fusion", "agent")}`)
     ? agentDir
@@ -1279,6 +1280,10 @@ function createReadOnlyPiSettingsView(cwd: string, agentDir: string): PackageMan
     getNpmCommand: () => Array.isArray(mergedSettings.npmCommand)
       ? [...mergedSettings.npmCommand]
       : undefined,
+    // Pi's SettingsManager defaults projects to trusted. Fusion workspaces are
+    // user-owned, so preserve pre-upgrade behavior and keep project-scoped
+    // .fusion resources loadable through the read-only settings view.
+    isProjectTrusted: () => true,
   };
 }