diff --git a/src/github/app.ts b/src/github/app.ts
index a929132482..2e447eca14 100644
--- a/src/github/app.ts
+++ b/src/github/app.ts
@@ -143,7 +143,7 @@ export async function createInstallationToken(
   return mint;
 }
 
-function githubErrorStatus(error: unknown): number | null {
+export function githubErrorStatus(error: unknown): number | null {
   const err = error as {
     status?: number;
     response?: { status?: number } | null;
diff --git a/src/services/agent-action-executor.ts b/src/services/agent-action-executor.ts
index 3d0defde8b..86fd39259a 100644
--- a/src/services/agent-action-executor.ts
+++ b/src/services/agent-action-executor.ts
@@ -1,8 +1,8 @@
 import { bumpPullRequestMergeAttempt, createPendingAgentActionIfAbsent, insertNotificationDeliveryIfAbsent, isGlobalAgentFrozen, markPullRequestApproved, markPullRequestMergeBlocked, recordAuditEvent } from "../db/repositories";
 import { classifyMergeFailure, MERGE_RETRY_CAP } from "./merge-failure";
 import { notifyActionToDiscord, notifyActionToSlack, type NotifyOutcome } from "./notify-discord";
-import { createInstallationToken } from "../github/app";
-import { fetchLiveCiAggregate } from "../github/backfill";
+import { createInstallationToken, githubErrorStatus } from "../github/app";
+import { fetchLiveCiAggregate, refreshInstallationHealthForInstallation } from "../github/backfill";
 import { githubRateLimitAdmissionKeyForToken } from "../github/client";
 import { ensurePullRequestLabel, removePullRequestLabel } from "../github/labels";
 import { closePullRequest, createIssueComment, createPullRequestReview, dismissLatestBotApproval, mergePullRequest, updatePullRequestBranch } from "../github/pr-actions";
@@ -181,6 +181,16 @@ export async function executeAgentMaintenanceActions(env: Env, ctx: AgentActionE
       if (action.actionClass === "merge" && ctx.headSha) {
         await handleMergeFailure(env, ctx, error);
       }
+      // #2265: a 403 on a PR-write mutation often means the LOCAL installations.permissions snapshot is stale —
+      // GitHub webhooks a consented permission UPGRADE but sends nothing for a maintainer-initiated downgrade, so
+      // the write-permission readiness gate (step 6 above) can keep reporting "ready" for up to the 30-minute
+      // health-refresh cron interval after a live downgrade. Opportunistically refresh now so the DB row (and
+      // therefore every later sweep/webhook read of it, for this or any other PR on the installation) self-heals
+      // immediately instead of waiting for the next cron tick. GitHub's own server-side enforcement (this very
+      // 403) is already the real backstop, so a failed refresh here is safe to swallow.
+      if (PR_WRITE_CLASSES.has(action.actionClass) && githubErrorStatus(error) === 403) {
+        await refreshInstallationHealthForInstallation(env, ctx.installationId).catch(() => undefined);
+      }
     }
   }
 
diff --git a/test/unit/agent-action-executor.test.ts b/test/unit/agent-action-executor.test.ts
index 43c31ec9cb..604aec1192 100644
--- a/test/unit/agent-action-executor.test.ts
+++ b/test/unit/agent-action-executor.test.ts
@@ -32,13 +32,14 @@ vi.mock("../../src/github/app", async (importOriginal) => ({
 vi.mock("../../src/github/backfill", async (importOriginal) => ({
   ...(await importOriginal<typeof import("../../src/github/backfill")>()),
   fetchLiveCiAggregate: vi.fn(async () => ({ ciState: "passed" as const, hasPending: false, hasVisiblePending: false, failingDetails: [], nonRequiredFailingDetails: [], ciCompletenessWarning: null })),
+  refreshInstallationHealthForInstallation: vi.fn(async () => null),
 }));
 
 import { closePullRequest, createIssueComment, createPullRequestReview, dismissLatestBotApproval, mergePullRequest, updatePullRequestBranch } from "../../src/github/pr-actions";
 import { ensurePullRequestLabel, removePullRequestLabel } from "../../src/github/labels";
 import { fetchPullRequestFreshness } from "../../src/github/pr-freshness";
 import { createInstallationToken } from "../../src/github/app";
-import { fetchLiveCiAggregate } from "../../src/github/backfill";
+import { fetchLiveCiAggregate, refreshInstallationHealthForInstallation } from "../../src/github/backfill";
 import { actionParams, executeAgentMaintenanceActions, pendingActionToPlanned, pendingClosureLabelApplied, type AgentActionExecutionContext, type AgentActionOutcome } from "../../src/services/agent-action-executor";
 import type { PlannedAgentAction } from "../../src/settings/agent-actions";
 import { AGENT_LABEL_PENDING_CLOSURE } from "../../src/review/linked-issue-hard-rules";
@@ -494,6 +495,38 @@ describe("executeAgentMaintenanceActions (#778 gate stack)", () => {
     expect(outcomes[0]?.detail).toMatch(/not mergeable/i);
     expect((await auditFor(env, "merge"))?.outcome).toBe("error");
   });
+
+  it("opportunistically refreshes installation health when a PR-write mutation fails with a 403 (#2265)", async () => {
+    const env = createTestEnv({});
+    vi.mocked(closePullRequest).mockRejectedValueOnce(Object.assign(new Error("Resource not accessible by integration"), { status: 403 }));
+    const outcomes = await executeAgentMaintenanceActions(env, ctx(), [close]);
+    expect(outcomes[0]?.outcome).toBe("error");
+    expect(refreshInstallationHealthForInstallation).toHaveBeenCalledTimes(1);
+    expect(refreshInstallationHealthForInstallation).toHaveBeenCalledWith(env, 123);
+  });
+
+  it("does not refresh installation health for a non-403 mutation failure (#2265)", async () => {
+    const env = createTestEnv({});
+    vi.mocked(closePullRequest).mockRejectedValueOnce(new Error("network timeout"));
+    await executeAgentMaintenanceActions(env, ctx(), [close]);
+    expect(refreshInstallationHealthForInstallation).not.toHaveBeenCalled();
+  });
+
+  it("does not refresh installation health on a 403 from a non-PR-write action (label uses issues:write, not pull_requests) (#2265)", async () => {
+    const env = createTestEnv({});
+    vi.mocked(ensurePullRequestLabel).mockRejectedValueOnce(Object.assign(new Error("Resource not accessible by integration"), { status: 403 }));
+    await executeAgentMaintenanceActions(env, ctx(), [label]);
+    expect(refreshInstallationHealthForInstallation).not.toHaveBeenCalled();
+  });
+
+  it("swallows a failed installation-health refresh — best-effort, does not affect the recorded outcome (#2265)", async () => {
+    const env = createTestEnv({});
+    vi.mocked(closePullRequest).mockRejectedValueOnce(Object.assign(new Error("Resource not accessible by integration"), { status: 403 }));
+    vi.mocked(refreshInstallationHealthForInstallation).mockRejectedValueOnce(new Error("refresh boom"));
+    const outcomes = await executeAgentMaintenanceActions(env, ctx(), [close]);
+    expect(outcomes[0]?.outcome).toBe("error");
+    expect((await auditFor(env, "close"))?.outcome).toBe("error");
+  });
 });
 
 describe("pendingClosureLabelApplied (#1136 Pass-2 trigger)", () => {