FN-7180: add configurable PR metadata prompts

Add project-scoped guidance fields for AI-generated Create PR metadata.

- Store PR title and description prompt guidance as project settings only.
- Surface editable guidance textareas in Project Models settings.
- Append trimmed guidance to the PR metadata system prompt without changing defaults for blank values.
- Document the settings and add release notes/tests for persistence, UI, and prompt generation.

Files changed:
 .changeset/fn-7180-pr-prompt-settings.md           |  7 ++
 docs/dashboard-guide.md                            |  1 +
 docs/settings-reference.md                         |  2 +
 .../core/src/__tests__/settings-defaults.test.ts   | 11 ++-
 packages/core/src/__tests__/store-settings.test.ts | 19 +++++
 packages/core/src/settings-schema.ts               |  2 +
 packages/core/src/types.ts                         | 12 ++++
 .../app/__tests__/settings-sections.test.tsx       | 54 ++++++++++++++
 .../dashboard/app/components/SettingsModal.tsx     |  4 ++
 .../settings/sections/ProjectModelsSection.tsx     | 12 ++++
 .../src/__tests__/pr-metadata-generator.test.ts    | 84 ++++++++++++++++++++++
 packages/dashboard/src/pr-metadata-generator.ts    | 23 ++++--
 12 files changed, 225 insertions(+), 6 deletions(-)

Fusion-Task-Id: FN-7180

Fusion-Task-Lineage: 9bdc42d5-ffd3-4208-b64a-96d142cc1dc8

Co-authored-by: Fusion (runfusion.ai) <noreply@runfusion.ai>

.changeset/fn-7180-pr-prompt-settings.md

@@ -0,0 +1,7 @@
+---
+"@runfusion/fusion": minor
+---
+
+summary: Add project settings to customize the AI prompts for PR title and description generation.
+category: feature
+dev: New project settings `prTitlePromptInstructions` / `prDescriptionPromptInstructions` (default undefined) are appended to the Create PR dialog's metadata-generation system prompt in generatePrMetadata.

docs/dashboard-guide.md

@@ -1004,6 +1004,7 @@ Inspect task definition, logs, review feedback, comments, artifacts, workflow ou
 - The **Create Pull Request** modal is a floating pop-out like Plan Mission, New Task, and Automations: drag its header or resize from desktop edges/corners, while mobile keeps the full-screen dialog layout. Close it with **X**, **Cancel**, or **Escape**; stray clicks inside or outside the floating shell do not dismiss it.
 - The modal shell renders immediately: preflight checks and PR options load independently of AI-generated title/body metadata, so slow AI suggestions no longer block base-branch selection, diagnostics, or manual PR authoring. The **Diff & commit preview** section starts collapsed and can be expanded on demand.
 - AI title/body generation in the dialog is bounded to 15 seconds and is canceled if the request disconnects; on timeout/cancel, Fusion falls back to deterministic task-based PR title/body content instead of leaving the spinner stuck forever.
+- Project Settings → Project Models includes optional **PR title prompt guidance** and **PR description prompt guidance** fields. Blank fields preserve the default Create PR metadata prompt; populated fields append guidance for the generated title or body sections.
 - The **Artifacts** tab combines task documents written by agents or users with task-scoped registered media artifacts. The gallery uses thumbnail-first image/video cards, image and video previews can expand into a dismissible full-size lightbox, video and audio use native controls, document artifacts show text previews, and generic artifacts open through their media URL.
 - The **Review** tab is separate from **Comments**: Review shows actionable PR/reviewer feedback and same-task revision controls, while Comments remains the general collaboration thread.
 - Review comments hide GitHub template HTML comments in both Markdown and Plain modes, show author avatars or User/Bot fallbacks, label Human vs Bot/agent authors, and include All/Human/Bot filtering.

docs/settings-reference.md

@@ -584,6 +584,8 @@ Default notes:
 | `titleSummarizerModelId` | `string` | `undefined` | Model ID for title summarization. |
 | `titleSummarizerFallbackProvider` | `string` | `undefined` | Fallback provider for title summarization. |
 | `titleSummarizerFallbackModelId` | `string` | `undefined` | Fallback model ID for title summarization. |
+| `prTitlePromptInstructions` | `string` | `undefined` | Optional project guidance appended to the Create PR dialog's AI metadata system prompt for the generated PR title. Blank or whitespace-only values are treated as unset and keep the default prompt behavior. |
+| `prDescriptionPromptInstructions` | `string` | `undefined` | Optional project guidance appended to the Create PR dialog's AI metadata system prompt for generated PR body fields (`summary`, `changes`, `testing`). Blank or whitespace-only values are treated as unset and keep the default prompt behavior. |
 | `scripts` | `Record<string, string>` | `undefined` | Named script map used by script-mode workflow steps and setup hooks. |
 | `setupScript` | `string` | `undefined` | Script key from `scripts` to run before task execution. |
 | `insightExtractionEnabled` | `boolean` | `false` | Enable scheduled memory insight extraction. |

packages/core/src/__tests__/settings-defaults.test.ts

@@ -1,7 +1,7 @@
 import { afterEach, describe, expect, it, vi } from "vitest";
 import { DEFAULT_MAX_AUTO_MERGE_RETRIES, resolveMaxAutoMergeRetries } from "../in-review-stall.js";
 import { isExperimentalFeatureEnabled } from "../experimental-features.js";
-import { DEFAULT_GLOBAL_SETTINGS, DEFAULT_PROJECT_SETTINGS } from "../settings-schema.js";
+import { DEFAULT_GLOBAL_SETTINGS, DEFAULT_PROJECT_SETTINGS, GLOBAL_SETTINGS_KEYS, PROJECT_SETTINGS_KEYS } from "../settings-schema.js";
 import { isWorkflowColumnsEnabled } from "../workflow-columns-settings.js";
 import {
   __resetLegacyCwdMainWarningForTests,
@@ -99,6 +99,15 @@ describe("settings defaults invariants", () => {
     expect("githubCloseSourceIssueOnDone" in DEFAULT_GLOBAL_SETTINGS).toBe(false);
   });
 
+  it("defaults PR metadata prompt guidance to project-scoped unset strings", () => {
+    expect(DEFAULT_PROJECT_SETTINGS.prTitlePromptInstructions).toBeUndefined();
+    expect(DEFAULT_PROJECT_SETTINGS.prDescriptionPromptInstructions).toBeUndefined();
+    expect(PROJECT_SETTINGS_KEYS).toContain("prTitlePromptInstructions");
+    expect(PROJECT_SETTINGS_KEYS).toContain("prDescriptionPromptInstructions");
+    expect(GLOBAL_SETTINGS_KEYS).not.toContain("prTitlePromptInstructions");
+    expect(GLOBAL_SETTINGS_KEYS).not.toContain("prDescriptionPromptInstructions");
+  });
+
   it("defaults AI merge commit summaries to enabled", () => {
     // FN-5642/FN-5644 intentionally default this on for subject + body summary coverage.
     expect(DEFAULT_PROJECT_SETTINGS.useAiMergeCommitSummary).toBe(true);

packages/core/src/__tests__/store-settings.test.ts

@@ -48,6 +48,25 @@ describe("TaskStore", () => {
     });
   });
 
+  describe("PR metadata prompt guidance settings", () => {
+    it("round-trips title and description prompt guidance via project settings", async () => {
+      await harness.store().updateSettings({
+        prTitlePromptInstructions: "Use release-note titles.",
+        prDescriptionPromptInstructions: "Group body bullets by operator impact.",
+      });
+
+      const settings = await harness.store().getSettings();
+      expect(settings.prTitlePromptInstructions).toBe("Use release-note titles.");
+      expect(settings.prDescriptionPromptInstructions).toBe("Group body bullets by operator impact.");
+
+      const { project, global } = await harness.store().getSettingsByScope();
+      expect(project.prTitlePromptInstructions).toBe("Use release-note titles.");
+      expect(project.prDescriptionPromptInstructions).toBe("Group body bullets by operator impact.");
+      expect("prTitlePromptInstructions" in global).toBe(false);
+      expect("prDescriptionPromptInstructions" in global).toBe(false);
+    });
+  });
+
   describe("worktreeCopyFiles setting", () => {
     it("round-trips populated copy-file paths via getSettings and project serialization", async () => {
       await harness.store().updateSettings({ worktreeCopyFiles: [".env", "config/local.env", "packages/api/.env.test"] });

packages/core/src/settings-schema.ts

@@ -483,6 +483,8 @@ export const DEFAULT_PROJECT_SETTINGS = {
   titleSummarizerModelId: undefined,
   titleSummarizerFallbackProvider: undefined,
   titleSummarizerFallbackModelId: undefined,
+  prTitlePromptInstructions: undefined,
+  prDescriptionPromptInstructions: undefined,
   scripts: undefined,
   setupScript: undefined,
   insightExtractionEnabled: false,

packages/core/src/types.ts

@@ -4229,6 +4229,18 @@ export interface ProjectSettings {
    *  planning fallback, then global fallback. Must be set together with
    *  `titleSummarizerFallbackProvider`. */
   titleSummarizerFallbackModelId?: string;
+  /**
+   * FNXC:PrMetadataGeneration 2026-06-27-00:00:
+   * Project operators can add title-specific guidance to the Create PR metadata prompt without replacing the strict JSON schema contract. Blank or whitespace-only values are treated as unset so the default prompt remains byte-for-byte unchanged.
+   * Optional project-scoped guidance appended to the PR metadata system prompt for the generated `title` field. Default: undefined.
+   */
+  prTitlePromptInstructions?: string;
+  /**
+   * FNXC:PrMetadataGeneration 2026-06-27-00:00:
+   * Project operators can add body-specific guidance to the Create PR metadata prompt without replacing the strict JSON schema contract. Blank or whitespace-only values are treated as unset so the default prompt remains byte-for-byte unchanged.
+   * Optional project-scoped guidance appended to the PR metadata system prompt for the generated `summary`, `changes`, and `testing` fields. Default: undefined.
+   */
+  prDescriptionPromptInstructions?: string;
   /** Named scripts that can be referenced by setupScript or other automation.
    *  A map of script name to shell command. */
   scripts?: Record<string, string>;

packages/dashboard/app/__tests__/settings-sections.test.tsx

@@ -17,6 +17,7 @@ import { AppearanceSection } from "../components/settings/sections/AppearanceSec
 import { NotificationsSection } from "../components/settings/sections/NotificationsSection";
 import { ExperimentalSection } from "../components/settings/sections/ExperimentalSection";
 import { MovedSettingsStub } from "../components/settings/sections/MovedSettingsStub";
+import { ProjectModelsSection } from "../components/settings/sections/ProjectModelsSection";
 import { PromptsSection } from "../components/settings/sections/PromptsSection";
 import { SecretsSection } from "../components/settings/sections/SecretsSection";
 import { WorktreesSection } from "../components/settings/sections/WorktreesSection";
@@ -218,6 +219,59 @@ describe("WorktreesSection", () => {
   });
 });
 
+describe("ProjectModelsSection", () => {
+  const models = {
+    modelLanes: [],
+    getLaneStatus: () => "inherited" as const,
+    getLaneValue: () => "",
+    updateLaneValue: vi.fn(),
+    resetLaneValue: vi.fn(),
+    availableModels: [],
+    modelsLoading: false,
+    favoriteProviders: [],
+    favoriteModels: [],
+    onToggleFavorite: vi.fn(),
+    onToggleModelFavorite: vi.fn(),
+    editingPresetId: null,
+    setEditingPresetId: vi.fn(),
+    presetDraft: null,
+    setPresetDraft: vi.fn(),
+    onSavePresetDraft: vi.fn(),
+    confirmDelete: vi.fn(),
+  };
+
+  it("renders PR prompt guidance textareas and emits edits through setForm", () => {
+    function ProjectModelsHost() {
+      const [form, setFormState] = useState<SettingsFormState>({
+        prTitlePromptInstructions: "Keep it short.",
+        prDescriptionPromptInstructions: "Mention testing.",
+      } as SettingsFormState);
+      return (
+        <ProjectModelsSection
+          scopeBanner={null}
+          form={form}
+          setForm={setFormState as never}
+          models={models}
+          addToast={vi.fn()}
+        />
+      );
+    }
+
+    render(<ProjectModelsHost />);
+
+    const titleField = screen.getByLabelText("PR title prompt guidance") as HTMLTextAreaElement;
+    const descriptionField = screen.getByLabelText("PR description prompt guidance") as HTMLTextAreaElement;
+    expect(titleField.value).toBe("Keep it short.");
+    expect(descriptionField.value).toBe("Mention testing.");
+
+    fireEvent.change(titleField, { target: { value: "Use release style." } });
+    fireEvent.change(descriptionField, { target: { value: "Group by impact." } });
+
+    expect(titleField.value).toBe("Use release style.");
+    expect(descriptionField.value).toBe("Group by impact.");
+  });
+});
+
 describe("PromptsSection", () => {
   it("renders the title and mounts AgentPromptsManager", () => {
     render(

packages/dashboard/app/components/SettingsModal.tsx

@@ -753,6 +753,8 @@ export function SettingsModal({
     webhookUrl: undefined,
     webhookFormat: "generic",
     webhookEvents: undefined,
+    prTitlePromptInstructions: "",
+    prDescriptionPromptInstructions: "",
   });
   const [loading, setLoading] = useState(true);
   // Guards the Save action against double-submit (rapid clicks / Enter) while the
@@ -2444,6 +2446,8 @@ export function SettingsModal({
         taskPrefix: form.taskPrefix?.trim() || undefined,
         githubTrackingDefaultRepo: form.githubTrackingDefaultRepo?.trim() || undefined,
         githubAuthToken: form.githubAuthToken?.trim() || undefined,
+        prTitlePromptInstructions: form.prTitlePromptInstructions?.trim() || undefined,
+        prDescriptionPromptInstructions: form.prDescriptionPromptInstructions?.trim() || undefined,
         overlapIgnorePaths: (form.overlapIgnorePaths ?? []).map((path) => path.trim()).filter((path) => path.length > 0),
         worktreeCopyFiles: normalizedWorktreeCopyFiles.length > 0 || initialScopedValues?.project?.worktreeCopyFiles !== undefined
           ? normalizedWorktreeCopyFiles

packages/dashboard/app/components/settings/sections/ProjectModelsSection.tsx

@@ -475,6 +475,18 @@ export function ProjectModelsSection({ scopeBanner, form, setForm, models, proje
       {(form.autoSummarizeTitles || form.useAiMergeCommitSummary || form.githubTrackingEnabledByDefault || false) && (<p className="settings-description">
           {t("settings.movedStub.summarizerModelInline", "The summarization model lane above controls title auto-summarization, merge commit summaries, GitHub tracking titles, and PR metadata generation.")}
         </p>)}
+
+      <div className="form-group">
+        <label htmlFor="prTitlePromptInstructions">{t("settings.projectModels.prTitlePromptInstructions", "PR title prompt guidance")}</label>
+        <textarea id="prTitlePromptInstructions" value={form.prTitlePromptInstructions || ""} onChange={(e) => setForm((f) => ({ ...f, prTitlePromptInstructions: e.target.value }))} rows={3} placeholder={t("settings.projectModels.prTitlePromptInstructionsPlaceholder", "Example: Use conventional-commit style and keep titles under 72 characters.")}/>
+        <small>{t("settings.projectModels.prTitlePromptInstructionsHelp", "Guides the AI-generated Create PR title. Leave blank to use the default PR metadata prompt.")}</small>
+      </div>
+
+      <div className="form-group">
+        <label htmlFor="prDescriptionPromptInstructions">{t("settings.projectModels.prDescriptionPromptInstructions", "PR description prompt guidance")}</label>
+        <textarea id="prDescriptionPromptInstructions" value={form.prDescriptionPromptInstructions || ""} onChange={(e) => setForm((f) => ({ ...f, prDescriptionPromptInstructions: e.target.value }))} rows={4} placeholder={t("settings.projectModels.prDescriptionPromptInstructionsPlaceholder", "Example: Emphasize operator-facing behavior and list verification commands exactly.")}/>
+        <small>{t("settings.projectModels.prDescriptionPromptInstructionsHelp", "Guides the AI-generated Create PR summary, changes, and testing sections. Leave blank to use the default PR metadata prompt.")}</small>
+      </div>
     </>);
 }
 export default ProjectModelsSection;

packages/dashboard/src/__tests__/pr-metadata-generator.test.ts

@@ -66,6 +66,17 @@ function expectFallbackBody(body: string) {
   expect(body).toContain("Closes FN-4991");
 }
 
+function capturedSystemPrompt(): string {
+  const call = vi.mocked(createFnAgent).mock.calls.at(-1)?.[0] as { systemPrompt?: string } | undefined;
+  return call?.systemPrompt ?? "";
+}
+
+const BASE_PR_METADATA_SYSTEM_PROMPT = [
+  "Generate GitHub PR metadata.",
+  "Respond with strict JSON only.",
+  "Schema: {title, summary, changes, testing, linkedTask}",
+].join("\n");
+
 describe("generatePrMetadata", () => {
   let repoRoot: string;
 
@@ -129,6 +140,79 @@ describe("generatePrMetadata", () => {
     expect(promptMock).toHaveBeenCalledWith(expect.any(String), expect.objectContaining({ signal: expect.any(AbortSignal) }));
   });
 
+  it("keeps the base PR metadata system prompt unchanged when guidance is unset", async () => {
+    const result = await generatePrMetadata({
+      task: createTask(),
+      repoRoot,
+      settings: {} as never,
+    });
+
+    expect(capturedSystemPrompt()).toBe(BASE_PR_METADATA_SYSTEM_PROMPT);
+    expect(capturedSystemPrompt()).toContain("Schema: {title, summary, changes, testing, linkedTask}");
+    expect(result.title).toBe("feat: add routes");
+    expect(result.body).toContain("## Summary");
+  });
+
+  it("adds only title guidance when title instructions are set", async () => {
+    const result = await generatePrMetadata({
+      task: createTask(),
+      repoRoot,
+      settings: { prTitlePromptInstructions: "  Use conventional commit style.  " } as never,
+    });
+
+    expect(capturedSystemPrompt()).toBe(`${BASE_PR_METADATA_SYSTEM_PROMPT}\nTitle guidance: Use conventional commit style.`);
+    expect(capturedSystemPrompt()).not.toContain("Description guidance:");
+    expect(result.title).toBe("feat: add routes");
+    expect(result.body).toContain("- pnpm test");
+  });
+
+  it("adds only description guidance when description instructions are set", async () => {
+    const result = await generatePrMetadata({
+      task: createTask(),
+      repoRoot,
+      settings: { prDescriptionPromptInstructions: "  Mention user-facing behavior.  " } as never,
+    });
+
+    expect(capturedSystemPrompt()).toBe(`${BASE_PR_METADATA_SYSTEM_PROMPT}\nDescription guidance: Mention user-facing behavior.`);
+    expect(capturedSystemPrompt()).not.toContain("Title guidance:");
+    expect(result.title).toBe("feat: add routes");
+    expect(result.body).toContain("Summary text");
+  });
+
+  it("adds both title and description guidance when both instructions are set", async () => {
+    const result = await generatePrMetadata({
+      task: createTask(),
+      repoRoot,
+      settings: {
+        prTitlePromptInstructions: "Use release-note tone.",
+        prDescriptionPromptInstructions: "Group changes by operator impact.",
+      } as never,
+    });
+
+    expect(capturedSystemPrompt()).toBe([
+      BASE_PR_METADATA_SYSTEM_PROMPT,
+      "Title guidance: Use release-note tone.",
+      "Description guidance: Group changes by operator impact.",
+    ].join("\n"));
+    expect(result.title).toBe("feat: add routes");
+    expect(result.body).toContain("## Changes");
+  });
+
+  it("treats whitespace-only PR prompt guidance as unset", async () => {
+    const result = await generatePrMetadata({
+      task: createTask(),
+      repoRoot,
+      settings: {
+        prTitlePromptInstructions: "   \n\t  ",
+        prDescriptionPromptInstructions: "  ",
+      } as never,
+    });
+
+    expect(capturedSystemPrompt()).toBe(BASE_PR_METADATA_SYSTEM_PROMPT);
+    expect(result.title).toBe("feat: add routes");
+    expect(result.body).toContain("## Testing");
+  });
+
   it("fills known sections when template exists and preserves unknown headings", async () => {
     mkdirSync(join(repoRoot, ".github"), { recursive: true });
     writeFileSync(

packages/dashboard/src/pr-metadata-generator.ts

@@ -270,6 +270,23 @@ export async function generatePrMetadata(input: {
     const template = templateExists ? await raceWithAbort(readFile(templatePath, "utf8"), combinedSignal) : "";
 
     const model = resolveTitleSummarizerSettingsModel(settings as Partial<Settings>);
+    const systemPrompt = [
+      "Generate GitHub PR metadata.",
+      "Respond with strict JSON only.",
+      "Schema: {title, summary, changes, testing, linkedTask}",
+    ];
+    const titleGuidance = settings.prTitlePromptInstructions?.trim();
+    const descriptionGuidance = settings.prDescriptionPromptInstructions?.trim();
+    /*
+     * FNXC:PrMetadataGeneration 2026-06-27-00:00:
+     * Custom project guidance augments the Create PR metadata generator only after trimming; unset or whitespace-only values must leave the base three-line strict-JSON system prompt byte-for-byte unchanged so existing parse/fallback behavior remains stable.
+     */
+    if (titleGuidance) {
+      systemPrompt.push(`Title guidance: ${titleGuidance}`);
+    }
+    if (descriptionGuidance) {
+      systemPrompt.push(`Description guidance: ${descriptionGuidance}`);
+    }
     const mcpServers = (await raceWithAbort(resolveMcpServersForStore(store ?? {}), combinedSignal)).servers;
     let aiText = "";
     const { session } = await raceWithAbort(createFnAgent({
@@ -282,11 +299,7 @@ export async function generatePrMetadata(input: {
       mcpServers,
       defaultProvider: model.provider,
       defaultModelId: model.modelId,
-      systemPrompt: [
+      systemPrompt: systemPrompt.join("\n"),
-        "Generate GitHub PR metadata.",
-        "Respond with strict JSON only.",
-        "Schema: {title, summary, changes, testing, linkedTask}",
-      ].join("\n"),
       onText: (delta: string) => {
         aiText += delta;
       },