fix(web): prioritize linked pull requests over automatic diffs

apps/web/src/components/ChatView.logic.test.ts

@@ -387,29 +387,35 @@ describe("proactive panels", () => {
     ).toBe(false);
   });
 
-  it("opens a completed turn diff only for changed files", () => {
-    const changedCheckpoint = {
-      status: "ready",
-      files: [{ path: "src/app.ts", kind: "modified", additions: 1, deletions: 0 }],
-    } satisfies Pick<TurnDiffSummary, "status" | "files">;
-    const unchangedCheckpoint = {
-      status: "ready",
-      files: [],
-    } satisfies Pick<TurnDiffSummary, "status" | "files">;
+  it.each([
+    { files: 0, additions: 0, deletions: 0, action: "ignore" },
+    { files: 1, additions: 1, deletions: 0, action: "ignore" },
+    { files: 2, additions: 12, deletions: 12, action: "ignore" },
+    { files: 1, additions: 25, deletions: 24, action: "ignore" },
+    { files: 1, additions: 25, deletions: 25, action: "open" },
+    { files: 1, additions: 0, deletions: 50, action: "open" },
+    { files: 3, additions: 1, deletions: 0, action: "open" },
+  ])(
+    "uses change size for automatic diffs: $files files, +$additions/-$deletions",
+    ({ files, additions, deletions, action }) => {
+      const changedCheckpoint = {
+        status: "ready",
+        files: Array.from({ length: files }, (_, index) => ({
+          path: `src/app-${index}.ts`,
+          kind: "modified" as const,
+          additions,
+          deletions,
+        })),
+      } satisfies Pick<TurnDiffSummary, "status" | "files">;
 
-    expect(
-      resolveProactiveTurnDiffAction({
-        checkpoint: changedCheckpoint,
-        isGitRepo: true,
-      }),
-    ).toBe("open");
-    expect(
-      resolveProactiveTurnDiffAction({
-        checkpoint: unchangedCheckpoint,
-        isGitRepo: true,
-      }),
-    ).toBe("ignore");
-  });
+      expect(
+        resolveProactiveTurnDiffAction({
+          checkpoint: changedCheckpoint,
+          isGitRepo: true,
+        }),
+      ).toBe(action);
+    },
+  );
 
   it("waits for definitive checkpoint and repository state", () => {
     const missingCheckpoint = {

apps/web/src/components/ChatView.logic.ts

@@ -189,7 +189,11 @@ export function resolveProactiveTurnDiffAction(input: {
   ) {
     return "ignore";
   }
-  return "open";
+  const changedLines = input.checkpoint.files.reduce(
+    (total, file) => total + file.additions + file.deletions,
+    0,
+  );
+  return input.checkpoint.files.length >= 3 || changedLines >= 50 ? "open" : "ignore";
 }
 
 export function codexArtifactTemplatePromptToAppend(

apps/web/src/components/ChatView.tsx

@@ -4514,9 +4514,10 @@ export default function ChatView(props: ChatViewProps) {
   }, [activeThreadRef]);
   const supportsThreadPullRequests =
     serverConfig?.environment.capabilities.threadPullRequests === true;
-  const visiblePullRequestCount = visibleThreadPullRequests(
+  const visiblePullRequests = visibleThreadPullRequests(
     (activeThreadShell ?? activeThread)?.pullRequests ?? [],
-  ).length;
+  );
+  const visiblePullRequestCount = visiblePullRequests.length;
   const pullRequestsSurfaceAvailable =
     isServerThread && supportsThreadPullRequests && visiblePullRequestCount > 0;
   const addPullRequestsSurface = useCallback(() => {
@@ -4616,6 +4617,7 @@ export default function ChatView(props: ChatViewProps) {
   );
   // The shell carries server PR updates even while thread detail is still loading.
   const activeThreadMetadata = activeThreadShell ?? activeThread;
+  const hasLinkedPullRequestDetail = activeThreadMetadata?.linkedPullRequest != null;
   const linkedThreadPullRequest =
     activeThreadMetadata?.linkedPullRequest ?? activeThreadMetadata?.branchPullRequest ?? null;
   const activeProjectRepository = activeProject?.repositoryIdentity?.displayName ?? null;
@@ -4626,6 +4628,11 @@ export default function ChatView(props: ChatViewProps) {
         linkedThreadPullRequest.number,
       ])
     : null;
+  const proactivePullRequestsKey = pullRequestsSurfaceAvailable
+    ? JSON.stringify(
+        visiblePullRequests.map((link) => [link.host, link.repository, link.number]).sort(),
+      )
+    : linkedThreadPullRequestKey;
   const observedThreadPullRequestRef = useRef<{
     readonly threadKey: string;
     readonly reference: ThreadLinkedPullRequest | null;
@@ -4692,7 +4699,40 @@ export default function ChatView(props: ChatViewProps) {
         userActionRevision,
       );
     }
-    if (!clientSettingsHydrated || threadDetailLoading) return;
+    if (!clientSettingsHydrated) return;
+
+    const proactivePanelsEnabled = settings.proactivePanelsEnabled && !shouldUseRightPanelSheet;
+    const eligibleLink =
+      proactivePanelsEnabled &&
+      shouldOpenProactivePullRequest(previousTargetKey, proactivePullRequestsKey);
+    const shouldDeferLink = eligibleLink && !pullRequestsCapabilityKnown;
+    proactivePanelObservationRef.current = {
+      ...observation,
+      targetKey: shouldDeferLink ? (previousTargetKey ?? null) : proactivePullRequestsKey,
+    };
+    if (eligibleLink && pullRequestsCapabilityKnown) {
+      if (
+        pullRequestsSurfaceAvailable &&
+        (visiblePullRequestCount > 1 || !hasLinkedPullRequestDetail || !supportsPullRequests)
+      ) {
+        panels.openProactive(
+          activeThreadRef,
+          { id: "pull-requests", kind: "pull-requests" },
+          userActionRevision,
+        );
+      } else if (
+        !followSelectedPullRequest &&
+        supportsPullRequests &&
+        linkedThreadPullRequest !== null
+      ) {
+        panels.openProactive(
+          activeThreadRef,
+          pullRequestSurface(linkedThreadPullRequest),
+          userActionRevision,
+        );
+      }
+    }
+    if (threadDetailLoading) return;
 
     const settledTurnId = latestTurnSettled ? (activeLatestTurn?.turnId ?? null) : null;
     const newlyCompletedTurnId = shouldOpenProactiveTurnDiff({
@@ -4703,8 +4743,13 @@ export default function ChatView(props: ChatViewProps) {
     })
       ? settledTurnId
       : null;
-    const proactivePanelsEnabled = settings.proactivePanelsEnabled && !shouldUseRightPanelSheet;
-    const eligibleCompletion = proactivePanelsEnabled && newlyCompletedTurnId !== null;
+    const eligibleCompletion =
+      proactivePanelsEnabled &&
+      newlyCompletedTurnId !== null &&
+      !(
+        proactivePullRequestsKey !== null &&
+        (!pullRequestsCapabilityKnown || supportsPullRequests || pullRequestsSurfaceAvailable)
+      );
     const completedCheckpoint = eligibleCompletion
       ? activeThread?.checkpoints.find((checkpoint) => checkpoint.turnId === newlyCompletedTurnId)
       : undefined;
@@ -4714,30 +4759,12 @@ export default function ChatView(props: ChatViewProps) {
           isGitRepo: gitStatusQuery.data?.isRepo,
         })
       : "ignore";
-    const eligibleLink =
-      proactivePanelsEnabled &&
-      shouldOpenProactivePullRequest(previousTargetKey, linkedThreadPullRequestKey);
-    const shouldDeferLink = eligibleLink && !pullRequestsCapabilityKnown;
     proactivePanelObservationRef.current = {
-      ...observation,
-      // Preserve first-entry eligibility while the checkpoint or repository is loading.
-      runningTurnId: diffAction === "defer" ? previousRunningTurnId : activeRunningTurnId,
-      targetKey: shouldDeferLink ? (previousTargetKey ?? null) : linkedThreadPullRequestKey,
+      ...proactivePanelObservationRef.current,
+      // Preserve first-entry eligibility while capabilities, checkpoint or repository load.
+      runningTurnId:
+        diffAction === "defer" || shouldDeferLink ? previousRunningTurnId : activeRunningTurnId,
     };
-
-    if (
-      !followSelectedPullRequest &&
-      eligibleLink &&
-      pullRequestsCapabilityKnown &&
-      supportsPullRequests &&
-      linkedThreadPullRequest !== null
-    ) {
-      panels.openProactive(
-        activeThreadRef,
-        pullRequestSurface(linkedThreadPullRequest),
-        userActionRevision,
-      );
-    }
     if (diffAction !== "open" || newlyCompletedTurnId === null) return;
     if (!panels.openProactive(activeThreadRef, { id: "diff", kind: "diff" }, userActionRevision)) {
       return;
@@ -4756,9 +4783,12 @@ export default function ChatView(props: ChatViewProps) {
     isServerThread,
     latestTurnSettled,
     linkedThreadPullRequest,
-    linkedThreadPullRequestKey,
+    proactivePullRequestsKey,
+    hasLinkedPullRequestDetail,
     onDiffPanelOpen,
     pullRequestsCapabilityKnown,
+    pullRequestsSurfaceAvailable,
+    visiblePullRequestCount,
     settings.proactivePanelsEnabled,
     shouldUseRightPanelSheet,
     supportsPullRequests,

apps/web/src/components/settings/SettingsPanels.tsx

@@ -2528,7 +2528,7 @@ export function GeneralSettingsPanel() {
 
         <SettingsRow
           {...searchableSetting("proactive-panels")}
-          description="Open linked pull requests when found and turn diffs when work changes files."
+          description="Open linked pull requests first. Otherwise, open turn diffs for changes to at least 3 files or 50 lines."
           resetAction={
             settings.proactivePanelsEnabled !== DEFAULT_UNIFIED_SETTINGS.proactivePanelsEnabled ? (
               <SettingResetButton

apps/web/src/rightPanelStore.test.ts

@@ -109,22 +109,27 @@ describe("rightPanelStore", () => {
     number: 42,
   });
 
-  it.each(["diff-first", "pull-request-first"])(
-    "prioritizes the linked pull request over browser and diff with %s delivery",
-    (order) => {
+  it.each([
+    { order: "diff-first", surface: linkedPullRequest },
+    { order: "pull-request-first", surface: linkedPullRequest },
+    { order: "diff-first", surface: { id: "pull-requests", kind: "pull-requests" } as const },
+    {
+      order: "pull-request-first",
+      surface: { id: "pull-requests", kind: "pull-requests" } as const,
+    },
+  ])(
+    "prioritizes $surface.kind over browser and diff with $order delivery",
+    ({ order, surface }) => {
       const store = useRightPanelStore.getState();
       store.openBrowser(refA, "existing-browser");
       const revision = store.getUserActionRevision(refA);
-      const requests =
-        order === "diff-first"
-          ? [completedDiff, linkedPullRequest]
-          : [linkedPullRequest, completedDiff];
+      const requests = order === "diff-first" ? [completedDiff, surface] : [surface, completedDiff];
       for (const surface of requests) store.openProactive(refA, surface, revision);
       store.reconcileBrowserSurfaces(refA, ["existing-browser", "agent-browser"]);
 
       expect(
         selectActiveRightPanelSurface(useRightPanelStore.getState().byThreadKey, refA),
-      ).toEqual(linkedPullRequest);
+      ).toEqual(surface);
 
       store.open(refA, "diff");
       expect(selectActiveRightPanel(useRightPanelStore.getState().byThreadKey, refA)).toBe("diff");
@@ -167,6 +172,9 @@ describe("rightPanelStore", () => {
 
     expect(store.openProactive(refA, completedDiff, revision)).toBe(false);
     expect(store.openProactive(refA, linkedPullRequest, revision)).toBe(false);
+    expect(
+      store.openProactive(refA, { id: "pull-requests", kind: "pull-requests" }, revision),
+    ).toBe(false);
     expect(selectThreadRightPanelState(useRightPanelStore.getState().byThreadKey, refA)).toBe(
       chosen,
     );

apps/web/src/rightPanelStore.ts

@@ -124,7 +124,7 @@ interface RightPanelStoreState {
    */
   openProactive: (
     ref: ScopedThreadRef,
-    surface: Extract<RightPanelSurface, { kind: "diff" | "pull-request" }>,
+    surface: Extract<RightPanelSurface, { kind: "diff" | "pull-request" | "pull-requests" }>,
     expectedUserActionRevision: number,
   ) => boolean;
   open: (
@@ -496,7 +496,8 @@ export const useRightPanelStore = create<RightPanelStoreState>()(
           // always apply, and later user choices reject both proactive requests.
           if (
             surface.kind === "diff" &&
-            selectActiveRightPanel(state.byThreadKey, ref) === "pull-request"
+            (selectActiveRightPanel(state.byThreadKey, ref) === "pull-request" ||
+              selectActiveRightPanel(state.byThreadKey, ref) === "pull-requests")
           ) {
             return state;
           }