Cache PR lookups and tighten project matching (#429)

- Reuse recent PR lookup results during git status
- Return null when a PR reference matches multiple projects
- Add coverage for cached lookups and ambiguous matches

Author: BunsDev

apps/server/src/git/Layers/GitManager.test.ts

@@ -758,6 +758,38 @@ it.layer(GitManagerTestLayer)("GitManager", (it) => {
     }),
   );
 
+  it.effect("status reuses cached PR lookup results for the same branch context", () =>
+    Effect.gen(function* () {
+      const repoDir = yield* makeTempDir("okcode-git-manager-");
+      yield* initRepo(repoDir);
+      yield* runGit(repoDir, ["checkout", "-b", "feature/status-cache"]);
+
+      const { manager, ghCalls } = yield* makeManager({
+        ghScenario: {
+          prListSequence: [
+            JSON.stringify([
+              {
+                number: 91,
+                title: "Cached PR",
+                url: "https://github.com/pingdotgg/codething-mvp/pull/91",
+                baseRefName: "main",
+                headRefName: "feature/status-cache",
+                state: "OPEN",
+                updatedAt: "2026-03-10T07:00:00Z",
+              },
+            ]),
+          ],
+        },
+      });
+
+      const first = yield* manager.status({ cwd: repoDir });
+      const second = yield* manager.status({ cwd: repoDir });
+
+      expect(first.pr).toEqual(second.pr);
+      expect(ghCalls.filter((call) => call.startsWith("pr list "))).toHaveLength(1);
+    }),
+  );
+
   it.effect("creates a commit when working tree is dirty", () =>
     Effect.gen(function* () {
       const repoDir = yield* makeTempDir("okcode-git-manager-");

apps/server/src/git/Layers/GitManager.ts

@@ -45,6 +45,11 @@ interface PullRequestInfo extends OpenPrInfo {
   updatedAt: string | null;
 }
 
+interface LatestPrLookupCacheEntry {
+  expiresAtMs: number;
+  pr: PullRequestInfo | null;
+}
+
 interface ResolvedPullRequest {
   number: number;
   title: string;
@@ -369,6 +374,8 @@ export const makeGitManager = Effect.gen(function* () {
   const gitCore = yield* GitCore;
   const gitHubCli = yield* GitHubCli;
   const textGeneration = yield* TextGeneration;
+  const latestPrLookupCache = new Map<string, LatestPrLookupCacheEntry>();
+  const LATEST_PR_LOOKUP_CACHE_TTL_MS = 15_000;
 
   const createProgressEmitter = (
     input: { cwd: string; action: "commit" | "commit_push" | "commit_push_pr" },
@@ -619,6 +626,13 @@ export const makeGitManager = Effect.gen(function* () {
   const findLatestPr = (cwd: string, details: { branch: string; upstreamRef: string | null }) =>
     Effect.gen(function* () {
       const headContext = yield* resolveBranchHeadContext(cwd, details);
+      const cacheKey = [cwd, headContext.headSelectors.join("\u0000")].join("\u0001");
+      const now = Date.now();
+      const cached = latestPrLookupCache.get(cacheKey);
+      if (cached && cached.expiresAtMs > now) {
+        return cached.pr;
+      }
+
       const parsedByNumber = new Map<number, PullRequestInfo>();
 
       for (const headSelector of headContext.headSelectors) {
@@ -663,10 +677,12 @@ export const makeGitManager = Effect.gen(function* () {
       });
 
       const latestOpenPr = parsed.find((pr) => pr.state === "open");
-      if (latestOpenPr) {
-        return latestOpenPr;
-      }
-      return parsed[0] ?? null;
+      const resolved = latestOpenPr ?? parsed[0] ?? null;
+      latestPrLookupCache.set(cacheKey, {
+        expiresAtMs: now + LATEST_PR_LOOKUP_CACHE_TTL_MS,
+        pr: resolved,
+      });
+      return resolved;
     });
 
   const resolveBaseBranch = (

apps/web/src/pullRequestProjectMatch.test.ts

@@ -64,4 +64,26 @@ describe("findProjectMatchingPullRequestReference", () => {
       ),
     ).toBeNull();
   });
+
+  it("returns null when multiple projects match the same repository slug", () => {
+    const projects = [
+      makeProject({
+        id: "project-1" as Project["id"],
+        name: "Psi Claw",
+        cwd: "/Users/buns/projects/psi-claw",
+      }),
+      makeProject({
+        id: "project-2" as Project["id"],
+        name: "Psi Claw",
+        cwd: "/Users/buns/projects/psi-claw-copy",
+      }),
+    ];
+
+    expect(
+      findProjectMatchingPullRequestReference(
+        projects,
+        "https://github.com/OpenKnots/psi-claw/pull/137",
+      ),
+    ).toBeNull();
+  });
 });

apps/web/src/pullRequestProjectMatch.ts

@@ -16,7 +16,7 @@ function normalizeRepositorySlug(input: string): string {
 }
 
 function projectRepositoryCandidates(project: Project): string[] {
-  const candidates = [project.name, lastPathSegment(project.cwd)]
+  const candidates = [lastPathSegment(project.cwd), project.name]
     .map(normalizeRepositorySlug)
     .filter((candidate) => candidate.length > 0);
 
@@ -37,8 +37,12 @@ export function findProjectMatchingPullRequestReference(
     return null;
   }
 
-  return (
-    projects.find((project) => projectRepositoryCandidates(project).includes(targetRepository)) ??
-    null
+  const matches = projects.filter((project) =>
+    projectRepositoryCandidates(project).includes(targetRepository),
   );
+  if (matches.length !== 1) {
+    return null;
+  }
+
+  return matches[0] ?? null;
 }