diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2e54360..ee3954b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,11 @@ All notable changes to `@testsprite/testsprite-cli` are documented here. The for
 
 ## [Unreleased]
 
+### Fixed
+
+- **`ci run` on `deployment_status` gates only an open pull request whose head is the deployed commit** (#550). A redeploy of a merged or closed pull request's head commit, or an open pull request that merely contains the commit, is now skipped with a `::notice::` and exit 0 (`no_pull_request`) instead of cloning an environment and gating it.
+- **The `deployment_status` pull-request lookup honors `--request-timeout` and survives a non-JSON reply** (#551). A GitHub API that never answers is exit 10 within the request budget instead of hanging the job, and a 200 with an HTML body (proxy, captive portal) is exit 10 with a clear message instead of an uncaught exception. 401/403 keep exit 5.
+
 ## [0.15.0] - 2026-10-17
 
 ### Added
diff --git a/src/commands/ci.ts b/src/commands/ci.ts
index 9e3eec2..fa5819a 100644
--- a/src/commands/ci.ts
+++ b/src/commands/ci.ts
@@ -5,6 +5,7 @@ import { Command } from 'commander';
 import {
   makeHttpClient,
   parseRequestTimeoutFlag,
+  resolveRequestTimeoutMs,
   type CommonOptions as FactoryCommonOptions,
 } from '../lib/client-factory.js';
 import { ApiError, CLIError, localValidationError } from '../lib/errors.js';
@@ -1327,7 +1328,10 @@ export async function runCiRun(opts: CiRunOptions, deps: TestDeps = {}): Promise
     throw err;
   }
 
-  const github = await readGithubRunContext(env, { fetchImpl: deps.fetchImpl });
+  const github = await readGithubRunContext(env, {
+    fetchImpl: deps.fetchImpl,
+    requestTimeoutMs: resolveRequestTimeoutMs(opts, env),
+  });
   let previewName: string | undefined;
   let githubTrigger: CiGithubTrigger | undefined;
   if (github.kind === 'pull_request') {
diff --git a/src/lib/github-context.test.ts b/src/lib/github-context.test.ts
index b5c5944..6a5d540 100644
--- a/src/lib/github-context.test.ts
+++ b/src/lib/github-context.test.ts
@@ -116,6 +116,134 @@ describe('readGithubRunContext', () => {
       },
     );
     expect(closed.kind).toBe('no_pull_request');
+    // Nor is a merged/closed pull request whose head IS the deployed commit (a redeploy after merge).
+    for (const state of ['closed', 'merged']) {
+      const done = await readGithubRunContext(
+        actionsEnv({ GITHUB_EVENT_NAME: 'deployment_status', GITHUB_TOKEN: 't' }),
+        {
+          ...eventFile({ deployment: { sha: SHA } }),
+          fetchImpl: githubApi([{ number: 7, state, head: { sha: SHA, ref: 'feat/done' } }]),
+        },
+      );
+      expect(done).toMatchObject({ kind: 'no_pull_request', event: 'deployment_status' });
+    }
+    // Nor an open PR that only contains the commit (branched off it): its head is another commit.
+    const containing = await readGithubRunContext(
+      actionsEnv({ GITHUB_EVENT_NAME: 'deployment_status', GITHUB_TOKEN: 't' }),
+      {
+        ...eventFile({ deployment: { sha: SHA } }),
+        fetchImpl: githubApi([
+          { number: 7, state: 'closed', head: { sha: SHA, ref: 'feat/done' } },
+          { number: 8, state: 'open', head: { sha: OTHER, ref: 'feat/next' } },
+        ]),
+      },
+    );
+    expect(containing).toMatchObject({ kind: 'no_pull_request', event: 'deployment_status' });
+  });
+
+  it('deployment_status: an open PR wins over a closed one with the same head commit', async () => {
+    const ctx = await readGithubRunContext(
+      actionsEnv({ GITHUB_EVENT_NAME: 'deployment_status', GITHUB_TOKEN: 't' }),
+      {
+        ...eventFile({ deployment: { sha: SHA } }),
+        fetchImpl: githubApi([
+          { number: 7, state: 'closed', head: { sha: SHA, ref: 'feat/old' } },
+          { number: 9, state: 'open', head: { sha: SHA, ref: 'feat/new' } },
+        ]),
+      },
+    );
+    expect(ctx).toMatchObject({ kind: 'pull_request', trigger: { prNumber: 9 } });
+  });
+
+  it('deployment_status: a lookup that never answers times out with exit 10 instead of hanging', async () => {
+    const hang = vi.fn(
+      (_url: string | URL | Request, init?: RequestInit) =>
+        new Promise<Response>((_resolve, reject) => {
+          init?.signal?.addEventListener('abort', () => reject(init.signal?.reason));
+        }),
+    ) as unknown as typeof globalThis.fetch;
+    const started = Date.now();
+    await expect(
+      readGithubRunContext(
+        actionsEnv({ GITHUB_EVENT_NAME: 'deployment_status', GITHUB_TOKEN: 't' }),
+        {
+          ...eventFile({ deployment: { sha: SHA } }),
+          fetchImpl: hang,
+          requestTimeoutMs: 50,
+        },
+      ),
+    ).rejects.toMatchObject({
+      exitCode: 10,
+      message: expect.stringContaining('did not answer within'),
+    });
+    expect(Date.now() - started).toBeLessThan(5_000);
+  });
+
+  it('deployment_status: a 200 whose body stalls past the timeout is reported as a timeout, exit 10', async () => {
+    const stall = vi.fn((_url: string | URL | Request, init?: RequestInit) => {
+      const body = new ReadableStream({
+        start(controller) {
+          init?.signal?.addEventListener('abort', () => controller.error(init.signal?.reason));
+        },
+      });
+      return Promise.resolve(
+        new Response(body, { status: 200, headers: { 'content-type': 'application/json' } }),
+      );
+    }) as unknown as typeof globalThis.fetch;
+    await expect(
+      readGithubRunContext(
+        actionsEnv({ GITHUB_EVENT_NAME: 'deployment_status', GITHUB_TOKEN: 't' }),
+        { ...eventFile({ deployment: { sha: SHA } }), fetchImpl: stall, requestTimeoutMs: 50 },
+      ),
+    ).rejects.toMatchObject({
+      exitCode: 10,
+      message: expect.stringContaining('did not finish answering within'),
+    });
+  });
+
+  it('deployment_status: a 200 that is not JSON (proxy, captive portal) is exit 10, not an uncaught crash', async () => {
+    const html = vi.fn(
+      async () =>
+        new Response('<html>sign in to the proxy</html>', {
+          status: 200,
+          headers: { 'content-type': 'text/html' },
+        }),
+    ) as unknown as typeof globalThis.fetch;
+    await expect(
+      readGithubRunContext(
+        actionsEnv({ GITHUB_EVENT_NAME: 'deployment_status', GITHUB_TOKEN: 't' }),
+        {
+          ...eventFile({ deployment: { sha: SHA } }),
+          fetchImpl: html,
+        },
+      ),
+    ).rejects.toMatchObject({ exitCode: 10, message: expect.stringContaining('not JSON') });
+  });
+
+  it('deployment_status: a body that breaks off mid-stream is exit 10 with its cause, not "not JSON"', async () => {
+    const broken = vi.fn(
+      async () =>
+        new Response(
+          new ReadableStream({
+            start(controller) {
+              controller.enqueue(new TextEncoder().encode('[{"number":'));
+              controller.error(new Error('socket hang up'));
+            },
+          }),
+          { status: 200, headers: { 'content-type': 'application/json' } },
+        ),
+    ) as unknown as typeof globalThis.fetch;
+    const failure = readGithubRunContext(
+      actionsEnv({ GITHUB_EVENT_NAME: 'deployment_status', GITHUB_TOKEN: 't' }),
+      { ...eventFile({ deployment: { sha: SHA } }), fetchImpl: broken },
+    );
+    await expect(failure).rejects.toMatchObject({
+      exitCode: 10,
+      message: expect.stringContaining('could not be read: socket hang up'),
+    });
+    await expect(failure).rejects.not.toMatchObject({
+      message: expect.stringContaining('not JSON'),
+    });
   });
 
   it('deployment_status: needs GITHUB_TOKEN, and a failed lookup never falls back to a guess', async () => {
diff --git a/src/lib/github-context.ts b/src/lib/github-context.ts
index 7153107..83fdd42 100644
--- a/src/lib/github-context.ts
+++ b/src/lib/github-context.ts
@@ -23,8 +23,13 @@ export interface GithubContextDeps {
   /** Reads `$GITHUB_EVENT_PATH`; injectable so tests never touch the runner. */
   readFile?: (path: string) => string;
   fetchImpl?: FetchImpl;
+  /** Budget for the GitHub pull-request lookup, as `--request-timeout` gives every other call. */
+  requestTimeoutMs?: number;
 }
 
+/** Same default as the HttpClient's per-request budget when no flag or env var sets one. */
+const DEFAULT_LOOKUP_TIMEOUT_MS = 30_000;
+
 /** The temporary environment a pull request's runs live in — shared with the GitHub App. */
 export function previewEnvironmentName(prNumber: number): string {
   return `github-pr-${prNumber}`;
@@ -86,14 +91,20 @@ export async function readGithubRunContext(
       );
     }
     const pulls = await listPullsForCommit(
-      { env, repoOwner, repoName, sha, token },
+      {
+        env,
+        repoOwner,
+        repoName,
+        sha,
+        token,
+        timeoutMs: deps.requestTimeoutMs ?? DEFAULT_LOOKUP_TIMEOUT_MS,
+      },
       deps.fetchImpl ?? globalThis.fetch,
     );
-    // The PR whose head IS this commit is the one this deployment belongs to.
-    // Anything looser (several open PRs, a merged one) is not a gate target.
-    const exact = pulls.filter(p => p.headSha === sha);
-    const open = pulls.filter(p => p.state === 'open');
-    const chosen = exact[0] ?? (open.length === 1 ? open[0] : undefined);
+    // Only an OPEN PR whose head IS this commit is the one this deployment belongs to.
+    // Anything looser (an open PR that merely contains the commit, a merged or closed one) is
+    // not a gate target: a redeploy of a merged PR's head commit must not clone an environment.
+    const chosen = pulls.find(p => p.headSha === sha && p.state === 'open');
     if (!chosen) {
       return {
         kind: 'no_pull_request',
@@ -152,7 +163,14 @@ interface PullSummary {
 }
 
 async function listPullsForCommit(
-  args: { env: NodeJS.ProcessEnv; repoOwner: string; repoName: string; sha: string; token: string },
+  args: {
+    env: NodeJS.ProcessEnv;
+    repoOwner: string;
+    repoName: string;
+    sha: string;
+    token: string;
+    timeoutMs: number;
+  },
   fetchImpl: FetchImpl,
 ): Promise<PullSummary[]> {
   const base = (args.env.GITHUB_API_URL ?? 'https://api.github.com').replace(/\/+$/, '');
@@ -166,10 +184,17 @@ async function listPullsForCommit(
         authorization: `Bearer ${args.token}`,
         'x-github-api-version': '2022-11-28',
       },
+      // Without a budget a GitHub API that never answers hangs the job until the runner kills it.
+      signal: AbortSignal.timeout(args.timeoutMs),
     });
   } catch (err) {
     throw new CLIError(
-      `Could not look up the pull request for commit ${args.sha.slice(0, 7)}: ${err instanceof Error ? err.message : String(err)}`,
+      `Could not look up the pull request for commit ${args.sha.slice(0, 7)}: ` +
+        (isTimeout(err)
+          ? `GitHub did not answer within ${Math.round(args.timeoutMs / 1000)}s`
+          : err instanceof Error
+            ? err.message
+            : String(err)),
       10,
     );
   }
@@ -182,7 +207,23 @@ async function listPullsForCommit(
       response.status === 401 || response.status === 403 ? 5 : 10,
     );
   }
-  const body: unknown = await response.json();
+  let body: unknown;
+  try {
+    body = await response.json();
+  } catch (err) {
+    // A proxy or captive portal answering 200 with HTML must be a transient failure, not an uncaught crash; so is
+    // a body that stalls until the timeout aborts it, which is reported as the timeout it is, and a connection that
+    // drops mid-body, which is reported with its own cause rather than as "not JSON".
+    throw new CLIError(
+      `Could not look up the pull request for commit ${args.sha.slice(0, 7)}: ` +
+        (isTimeout(err)
+          ? `GitHub did not finish answering within ${Math.round(args.timeoutMs / 1000)}s`
+          : err instanceof SyntaxError
+            ? `GitHub answered ${response.status} with a body that is not JSON`
+            : `GitHub's ${response.status} response body could not be read: ${err instanceof Error ? err.message : String(err)}`),
+      10,
+    );
+  }
   if (!Array.isArray(body)) return [];
   return body.flatMap((item): PullSummary[] => {
     const pr = asRecord(item);
@@ -205,3 +246,7 @@ function asRecord(value: unknown): Record<string, unknown> | undefined {
     ? (value as Record<string, unknown>)
     : undefined;
 }
+
+function isTimeout(err: unknown): boolean {
+  return err instanceof Error && (err.name === 'TimeoutError' || err.name === 'AbortError');
+}