fix(server): threads no longer settle after merging PRs they were asked to merge

apps/server/src/orchestration-v2/ThreadSettlementService.test.ts

@@ -358,6 +358,53 @@ describe("resolveAutoSettlementAt", () => {
     ).toBeNull();
   });
 
+  it("does not settle on pull requests that were already merged when linked", () => {
+    const link = (number: number, linkedAt: DateTime.Utc, mergedAt: DateTime.Utc) => ({
+      host: "example.test",
+      repository: "owner/repository",
+      number,
+      url: `https://example.test/owner/repository/pull/${number}`,
+      source: "agent" as const,
+      linkedAt: DateTime.formatIso(linkedAt),
+      snapshot: {
+        state: "merged" as const,
+        title: "Pull request",
+        headBranch: `feature-${number}`,
+        baseBranch: "main",
+        isDraft: false,
+        updatedAt: DateTime.formatIso(mergedAt),
+        syncedAt: DateTime.formatIso(linkedAt),
+        mergedAt: DateTime.formatIso(mergedAt),
+      },
+      stack: null,
+    });
+    // The user asked the agent to merge pull requests; it merged one, then
+    // linked it to the thread as a record of the work.
+    const recorded = link(1, at(-50 * 60 * 1_000), at(-55 * 60 * 1_000));
+    const input = {
+      thread: shell({
+        latestUserMessageAt: at(-2 * 60 * 60 * 1_000),
+        latestRunCompletedAt: at(-45 * 60 * 1_000),
+        pullRequests: [recorded],
+      }),
+      pullRequest: null,
+      nowMs: NOW_MS,
+      autoSettleAfterDays: null,
+      autoSettleOnMerge: true,
+    };
+    expect(ThreadSettlementService.resolveAutoSettlementAt(input)).toBeNull();
+    // A pull request linked while open still settles the thread when it merges.
+    expect(
+      ThreadSettlementService.resolveAutoSettlementAt({
+        ...input,
+        thread: {
+          ...input.thread,
+          pullRequests: [recorded, link(2, at(-90 * 60 * 1_000), at(-40 * 60 * 1_000))],
+        },
+      }),
+    ).toEqual(at(-45 * 60 * 1_000));
+  });
+
   it("settles inactive threads even when their pull request remains open", () => {
     const input = {
       thread: shell({ latestUserMessageAt: at(-30 * DAY_MS) }),
@@ -833,6 +880,64 @@ describe("ThreadSettlementServiceV2 worker", () => {
     ),
   );
 
+  it.effect("does not look up a pull request that was already merged when linked", () =>
+    Effect.scoped(
+      Effect.gen(function* () {
+        yield* TestClock.setTime(Date.parse(NOW));
+        const reference = {
+          projectId: PROJECT_ID,
+          repository: "owner/repository",
+          number: 42,
+          url: "https://example.test/owner/repository/pull/42",
+        };
+        const fixture = yield* makeHarness({
+          snapshot: makeSnapshot([
+            makeThread("merged-then-linked", {
+              linkedPullRequest: reference,
+              pullRequests: [
+                {
+                  host: "example.test",
+                  repository: reference.repository,
+                  number: reference.number,
+                  url: reference.url,
+                  source: "agent",
+                  linkedAt: "2026-08-28T00:00:00.000Z",
+                  snapshot: {
+                    state: "merged",
+                    title: "Pull request",
+                    headBranch: "feature",
+                    baseBranch: "main",
+                    isDraft: false,
+                    updatedAt: "2026-08-27T00:00:00.000Z",
+                    syncedAt: "2026-08-28T00:00:00.000Z",
+                    mergedAt: "2026-08-27T00:00:00.000Z",
+                  },
+                  stack: null,
+                },
+              ],
+            }),
+          ]),
+          settings: {
+            ...DEFAULT_SERVER_SETTINGS,
+            sidebarAutoSettleAfterDays: null,
+            sidebarAutoSettleOnMerge: true,
+          },
+          pullRequestSummary: (input) =>
+            Effect.succeed({
+              ...makePullRequestSummary({ ...input, state: "merged" }),
+              mergedAt: "2026-08-27T00:00:00.000Z",
+            }),
+        });
+        yield* Effect.gen(function* () {
+          const reactor = yield* ThreadSettlementService.ThreadSettlementServiceV2;
+          yield* startHarness(reactor, fixture.activation, fixture.snapshotReads);
+          assert.deepStrictEqual(yield* Ref.get(fixture.commands), []);
+          assert.deepStrictEqual(yield* Ref.get(fixture.summaryCalls), []);
+        }).pipe(Effect.provide(fixture.layer));
+      }),
+    ),
+  );
+
   it.effect("reevaluates immediately after a pull request merge", () =>
     Effect.scoped(
       Effect.gen(function* () {

apps/server/src/orchestration-v2/ThreadSettlementService.ts

@@ -77,6 +77,34 @@ function pullRequestMatchesProject(
   );
 }
 
+type SettlementPullRequestLink = NonNullable<
+  ProjectionStore.ProjectionSettlementCandidate["pullRequests"]
+>[number];
+
+/** When the linked pull request merged or closed, or -Infinity if it has not. */
+function linkTerminalAtMs(link: SettlementPullRequestLink): number {
+  const snapshot = link.snapshot;
+  const value = snapshot?.state === "merged" ? snapshot.mergedAt : snapshot?.closedAt;
+  const timestamp = Date.parse(value ?? "");
+  return Number.isNaN(timestamp) ? Number.NEGATIVE_INFINITY : timestamp;
+}
+
+/**
+ * The links whose outcome the thread waits on. A link made after its pull
+ * request had already merged or closed records work the thread did, such as an
+ * agent merging pull requests it was asked to merge, so it cannot settle the
+ * thread.
+ */
+function settlementPullRequestLinks(
+  links: ReadonlyArray<SettlementPullRequestLink>,
+): ReadonlyArray<SettlementPullRequestLink> {
+  return visibleThreadPullRequests(links).filter((link) => {
+    if (link.snapshot === null || link.snapshot.state === "open") return true;
+    const linkedAtMs = Date.parse(link.linkedAt);
+    return Number.isNaN(linkedAtMs) || linkTerminalAtMs(link) >= linkedAtMs;
+  });
+}
+
 /**
  * A recent user message stays queued until a run adopts its timestamp.
  * Absolute age bounds client clock skew in both directions and stops stale
@@ -205,17 +233,11 @@ export function resolveAutoSettlementAt(input: {
 }): DateTime.Utc | null {
   const { thread } = input;
   let pullRequest = input.pullRequest;
-  const links = visibleThreadPullRequests(thread.pullRequests ?? []);
+  const links = settlementPullRequestLinks(thread.pullRequests ?? []);
   if (links.some((link) => link.snapshot === null || link.snapshot.state === "open")) return null;
   if (links.length > 0) {
-    const terminalAt = (link: (typeof links)[number]) => {
-      const snapshot = link.snapshot;
-      const value = snapshot?.state === "merged" ? snapshot.mergedAt : snapshot?.closedAt;
-      const timestamp = Date.parse(value ?? "");
-      return Number.isNaN(timestamp) ? Number.NEGATIVE_INFINITY : timestamp;
-    };
     const latest = links.reduce((current, candidate) =>
-      terminalAt(candidate) > terminalAt(current) ? candidate : current,
+      linkTerminalAtMs(candidate) > linkTerminalAtMs(current) ? candidate : current,
     );
     pullRequest =
       latest.snapshot === null