fix: include PR titles in generated task names

Generated-By: PostHog Code
Task-Id: 0c226c8d-1b4d-4527-8d8c-2c0819279f10

Author: MattPua

packages/core/src/sessions/titleGeneratorService.test.ts

@@ -220,6 +220,26 @@ describe("generateTitleAndSummary", () => {
     expect(result?.title).toBe("Fix login bug");
   });
 
+  it("instructs the model to include existing GitHub PR titles", async () => {
+    prompt.mockResolvedValue({
+      content:
+        "TITLE: Review PR #123: Fix login redirect\nSUMMARY: Reviewing the existing pull request.",
+    });
+
+    await makeService().generateTitleAndSummary(
+      '<github_pr number="123" title="Fix login redirect" url="https://github.com/org/repo/pull/123" />',
+    );
+
+    expect(prompt).toHaveBeenCalledWith(
+      expect.anything(),
+      expect.objectContaining({
+        system: expect.stringContaining(
+          "the generated TITLE MUST include both the PR number and the PR title verbatim",
+        ),
+      }),
+    );
+  });
+
   it("returns null on error", async () => {
     prompt.mockRejectedValue(new Error("network error"));
     const result = await makeService().generateTitleAndSummary("some content");

packages/core/src/sessions/titleGeneratorService.ts

@@ -40,6 +40,7 @@ Title rules:
 - Remove: the, this, my, a, an
 - If possible, start with action verbs (Fix, Implement, Analyze, Debug, Update, Research, Review)
 - Keep exact: technical terms, numbers, filenames, HTTP codes, PR numbers
+- GitHub PR rule: If the content contains a <github_pr> with a non-empty title, the generated TITLE MUST include both the PR number and the PR title verbatim. This rule overrides the 6-word title limit. Never replace the PR title with a generic phrase. Before responding, verify that both values appear in TITLE.
 - Never assume tech stack
 - Only output "Untitled" if the input is completely null/missing, not just unclear
 - If the input is a URL (e.g. a GitHub issue link, PR link, or any web URL), generate a title based on what you can infer from the URL structure (repo name, issue/PR number, etc.). Never say you cannot access URLs or ask the user for more information.
@@ -58,6 +59,7 @@ Title examples:
 - "Update user documentation for new API endpoints" → Update API documentation
 - "Research competitor pricing strategies for our product" → Research competitor pricing
 - "Review pull request #123" → Review pull request #123
+- "<github_pr number="123" title="Fix login redirect" url="https://github.com/org/repo/pull/123" />" → Review PR #123: Fix login redirect
 - "debug 500 errors in production" → Debug production 500 errors
 - "why is the payment flow failing" → Analyze payment flow failure
 - "So how about that weather huh" → Weather chat