diff --git a/src/main/services/oauth/anthropic-claude-flow.ts b/src/main/services/oauth/anthropic-claude-flow.ts
index df8907b8..a3f885cf 100644
--- a/src/main/services/oauth/anthropic-claude-flow.ts
+++ b/src/main/services/oauth/anthropic-claude-flow.ts
@@ -9,6 +9,7 @@ import { startOAuthCallbackServer } from "./oauth-callback-server";
 import { generatePkce } from "./pkce";
 import type { OAuthCredentials, OAuthFlow, OAuthLoginCallbacks } from "./oauth-types";
 import { httpFailure } from "../provider-http";
+import { oauthFetch } from "./oauth-fetch";
 
 const CLIENT_ID = "9d1c250a-e61b-44d9-88ed-5944d1962f5e";
 const AUTHORIZE_URL = "https://claude.ai/oauth/authorize";
@@ -32,8 +33,8 @@ function buildAuthorizeUrl(challenge: string, state: string): string {
   return `${AUTHORIZE_URL}?${params.toString()}`;
 }
 
-async function exchangeCode(code: string, state: string, verifier: string): Promise<OAuthCredentials> {
-  const response = await fetch(TOKEN_URL, {
+async function exchangeCode(code: string, state: string, verifier: string, cancel?: AbortSignal): Promise<OAuthCredentials> {
+  const { response, text } = await oauthFetch(TOKEN_URL, {
     method: "POST",
     headers: { "Content-Type": "application/json", Accept: "application/json" },
     body: JSON.stringify({
@@ -44,8 +45,7 @@ async function exchangeCode(code: string, state: string, verifier: string): Prom
       redirect_uri: REDIRECT_URI,
       code_verifier: verifier,
     }),
-  });
-  const text = await response.text();
+  }, cancel);
   if (!response.ok) throw new Error(`Token exchange failed: ${response.status} ${text}`);
   const json = JSON.parse(text) as { access_token?: unknown; refresh_token?: unknown; expires_in?: unknown };
   if (typeof json.access_token !== "string" || typeof json.refresh_token !== "string" || typeof json.expires_in !== "number") {
@@ -56,12 +56,11 @@ async function exchangeCode(code: string, state: string, verifier: string): Prom
 
 /** Refresh an expired Claude Pro/Max access token. */
 export async function refreshClaudePro(refreshToken: string): Promise<OAuthCredentials> {
-  const response = await fetch(TOKEN_URL, {
+  const { response, text } = await oauthFetch(TOKEN_URL, {
     method: "POST",
     headers: { "Content-Type": "application/json", Accept: "application/json" },
     body: JSON.stringify({ grant_type: "refresh_token", client_id: CLIENT_ID, refresh_token: refreshToken }),
   });
-  const text = await response.text();
   if (!response.ok) throw httpFailure(`Claude token refresh failed: ${response.status} ${text}`, response, text);
   const json = JSON.parse(text) as { access_token?: unknown; refresh_token?: unknown; expires_in?: unknown };
   if (typeof json.access_token !== "string" || typeof json.refresh_token !== "string" || typeof json.expires_in !== "number") {
@@ -79,7 +78,7 @@ export const anthropicClaudeFlow: OAuthFlow = {
       callbacks.onAuth({ url: buildAuthorizeUrl(challenge, verifier), instructions: "Complete the Claude sign-in in your browser." });
       const result = await server.waitForCode();
       if (result.state !== verifier) throw new Error("OAuth state mismatch.");
-      return await exchangeCode(result.code, result.state, verifier);
+      return await exchangeCode(result.code, result.state, verifier, callbacks.signal);
     } finally {
       server.close();
     }
diff --git a/src/main/services/oauth/github-copilot-flow.ts b/src/main/services/oauth/github-copilot-flow.ts
index 32b3b022..ef3c7dbb 100644
--- a/src/main/services/oauth/github-copilot-flow.ts
+++ b/src/main/services/oauth/github-copilot-flow.ts
@@ -7,6 +7,7 @@
 import { listProviderModels } from "../../../shared/provider-models";
 import type { OAuthCredentials, OAuthFlow, OAuthLoginCallbacks } from "./oauth-types";
 import { httpFailure } from "../provider-http";
+import { oauthFetch } from "./oauth-fetch";
 
 // Decoded from the published GitHub Copilot client id used by the official CLI.
 const CLIENT_ID = "Iv1.b507a08c87ecfe98";
@@ -44,13 +45,10 @@ function getUrls(domain: string): CopilotUrls {
   };
 }
 
-async function fetchJson(url: string, init: RequestInit): Promise<Record<string, unknown>> {
-  const response = await fetch(url, init);
-  if (!response.ok) {
-    const text = await response.text().catch(() => "");
-    throw httpFailure(`${response.status} ${response.statusText}: ${text}`, response, text);
-  }
-  return (await response.json()) as Record<string, unknown>;
+async function fetchJson(url: string, init: RequestInit, cancel?: AbortSignal): Promise<Record<string, unknown>> {
+  const { response, text } = await oauthFetch(url, init, cancel);
+  if (!response.ok) throw httpFailure(`${response.status} ${response.statusText}: ${text}`, response, text);
+  return JSON.parse(text) as Record<string, unknown>;
 }
 
 interface DeviceCode {
@@ -61,7 +59,7 @@ interface DeviceCode {
   expires_in: number;
 }
 
-async function startDeviceFlow(domain: string): Promise<DeviceCode> {
+async function startDeviceFlow(domain: string, cancel?: AbortSignal): Promise<DeviceCode> {
   const data = await fetchJson(getUrls(domain).deviceCodeUrl, {
     method: "POST",
     headers: {
@@ -70,7 +68,7 @@ async function startDeviceFlow(domain: string): Promise<DeviceCode> {
       "User-Agent": COPILOT_HEADERS["User-Agent"],
     },
     body: new URLSearchParams({ client_id: CLIENT_ID, scope: "read:user" }),
-  });
+  }, cancel);
   const deviceCode = data.device_code;
   const userCode = data.user_code;
   const verificationUri = data.verification_uri;
@@ -148,7 +146,7 @@ async function pollForGitHubAccessToken(domain: string, device: DeviceCode, sign
         device_code: device.device_code,
         grant_type: "urn:ietf:params:oauth:grant-type:device_code",
       }),
-    });
+    }, signal);
     const decision = interpretPollResponse(raw);
     if (decision.kind === "token") return decision.accessToken;
     if (decision.kind === "error") throw new Error(decision.message);
@@ -160,11 +158,11 @@ async function pollForGitHubAccessToken(domain: string, device: DeviceCode, sign
   throw new Error("Device flow timed out. Please try signing in again.");
 }
 
-export async function refreshGitHubCopilotToken(githubToken: string, enterpriseDomain?: string | null): Promise<OAuthCredentials> {
+export async function refreshGitHubCopilotToken(githubToken: string, enterpriseDomain?: string | null, cancel?: AbortSignal): Promise<OAuthCredentials> {
   const domain = enterpriseDomain || "github.com";
   const raw = await fetchJson(getUrls(domain).copilotTokenUrl, {
     headers: { Accept: "application/json", Authorization: `Bearer ${githubToken}`, ...COPILOT_HEADERS },
-  });
+  }, cancel);
   const token = raw.token;
   const expiresAt = raw.expires_at;
   if (typeof token !== "string" || typeof expiresAt !== "number") {
@@ -186,12 +184,12 @@ export function copilotBaseUrl(token: string, enterpriseDomain?: string | null):
 }
 
 /** Best-effort model policy enablement, matching the official client behaviour. */
-async function enableCopilotModels(token: string, enterpriseDomain?: string | null): Promise<void> {
+async function enableCopilotModels(token: string, enterpriseDomain?: string | null, cancel?: AbortSignal): Promise<void> {
   const baseUrl = copilotBaseUrl(token, enterpriseDomain);
   await Promise.all(
     listProviderModels("github-copilot").map(async (model) => {
       try {
-        await fetch(`${baseUrl}/models/${model.id}/policy`, {
+        await oauthFetch(`${baseUrl}/models/${model.id}/policy`, {
           method: "POST",
           headers: {
             "Content-Type": "application/json",
@@ -201,9 +199,10 @@ async function enableCopilotModels(token: string, enterpriseDomain?: string | nu
             "x-interaction-type": "chat-policy",
           },
           body: JSON.stringify({ state: "enabled" }),
-        });
-      } catch {
-        // Per-model enablement is advisory; the model may already be enabled.
+        }, cancel);
+      } catch (error) {
+        // Per-model enablement is advisory (the model may already be enabled); a cancelled sign-in still ends here.
+        if (cancel?.aborted) throw error;
       }
     }),
   );
@@ -214,15 +213,15 @@ export const githubCopilotFlow: OAuthFlow = {
   async login(callbacks: OAuthLoginCallbacks): Promise<OAuthCredentials> {
     const enterpriseDomain = normalizeDomain(callbacks.enterpriseDomain);
     const domain = enterpriseDomain ?? "github.com";
-    const device = await startDeviceFlow(domain);
+    const device = await startDeviceFlow(domain, callbacks.signal);
     callbacks.onAuth({
       url: device.verification_uri,
       instructions: `Enter code ${device.user_code} at ${device.verification_uri}`,
     });
     const githubToken = await pollForGitHubAccessToken(domain, device, callbacks.signal);
-    const credentials = await refreshGitHubCopilotToken(githubToken, enterpriseDomain ?? undefined);
+    const credentials = await refreshGitHubCopilotToken(githubToken, enterpriseDomain ?? undefined, callbacks.signal);
     callbacks.onProgress?.("Enabling Copilot models");
-    await enableCopilotModels(credentials.access, enterpriseDomain ?? undefined);
+    await enableCopilotModels(credentials.access, enterpriseDomain ?? undefined, callbacks.signal);
     return credentials;
   },
 };
diff --git a/src/main/services/oauth/google-antigravity-flow.ts b/src/main/services/oauth/google-antigravity-flow.ts
index f96e28a5..643fa962 100644
--- a/src/main/services/oauth/google-antigravity-flow.ts
+++ b/src/main/services/oauth/google-antigravity-flow.ts
@@ -8,6 +8,7 @@ import { startOAuthCallbackServer } from "./oauth-callback-server";
 import { generatePkce } from "./pkce";
 import type { OAuthCredentials, OAuthFlow, OAuthLoginCallbacks } from "./oauth-types";
 import { httpFailure } from "../provider-http";
+import { oauthFetch } from "./oauth-fetch";
 
 const CLIENT_ID = "1071006060591-tmhssin2h21lcre235vtolojh4g403ep.apps.googleusercontent.com";
 const CALLBACK_PORT = 51121;
@@ -44,8 +45,8 @@ function buildAuthorizeUrl(challenge: string, state: string): string {
   return `${AUTH_URL}?${params.toString()}`;
 }
 
-async function exchangeCode(code: string, verifier: string, clientSecret: string): Promise<{ access: string; refresh: string; expires: number }> {
-  const response = await fetch(TOKEN_URL, {
+async function exchangeCode(code: string, verifier: string, clientSecret: string, cancel?: AbortSignal): Promise<{ access: string; refresh: string; expires: number }> {
+  const { response, text } = await oauthFetch(TOKEN_URL, {
     method: "POST",
     headers: { "Content-Type": "application/x-www-form-urlencoded" },
     body: new URLSearchParams({
@@ -56,12 +57,9 @@ async function exchangeCode(code: string, verifier: string, clientSecret: string
       redirect_uri: REDIRECT_URI,
       code_verifier: verifier,
     }),
-  });
-  if (!response.ok) {
-    const text = await response.text().catch(() => "");
-    throw new Error(`Token exchange failed: ${response.status} ${text}`);
-  }
-  const json = (await response.json()) as { access_token?: unknown; refresh_token?: unknown; expires_in?: unknown };
+  }, cancel);
+  if (!response.ok) throw new Error(`Token exchange failed: ${response.status} ${text}`);
+  const json = JSON.parse(text) as { access_token?: unknown; refresh_token?: unknown; expires_in?: unknown };
   if (typeof json.access_token !== "string" || typeof json.refresh_token !== "string" || typeof json.expires_in !== "number") {
     throw new Error("Token response was missing required fields.");
   }
@@ -79,7 +77,7 @@ export function readProjectId(payload: Record<string, unknown>): string | null {
   return null;
 }
 
-async function discoverProject(accessToken: string): Promise<string> {
+async function discoverProject(accessToken: string, cancel?: AbortSignal): Promise<string> {
   const headers = {
     Authorization: `Bearer ${accessToken}`,
     "Content-Type": "application/json",
@@ -87,17 +85,18 @@ async function discoverProject(accessToken: string): Promise<string> {
   };
   for (const endpoint of CODE_ASSIST_ENDPOINTS) {
     try {
-      const response = await fetch(`${endpoint}/v1internal:loadCodeAssist`, {
+      const { response, text } = await oauthFetch(`${endpoint}/v1internal:loadCodeAssist`, {
         method: "POST",
         headers,
         body: JSON.stringify({ metadata: { ideType: "IDE_UNSPECIFIED", platform: "PLATFORM_UNSPECIFIED", pluginType: "GEMINI" } }),
-      });
+      }, cancel);
       if (response.ok) {
-        const projectId = readProjectId((await response.json()) as Record<string, unknown>);
+        const projectId = readProjectId(JSON.parse(text) as Record<string, unknown>);
         if (projectId) return projectId;
       }
-    } catch {
-      // Try the next endpoint.
+    } catch (error) {
+      // A cancelled sign-in ends here; any other failure moves on to the next endpoint.
+      if (cancel?.aborted) throw error;
     }
   }
   throw new Error("Antigravity project discovery failed.");
@@ -105,7 +104,7 @@ async function discoverProject(accessToken: string): Promise<string> {
 
 /** Refresh an expired Antigravity access token, retaining the project id. */
 export async function refreshAntigravity(refreshToken: string, projectId: string, clientSecret: string): Promise<OAuthCredentials> {
-  const response = await fetch(TOKEN_URL, {
+  const { response, text } = await oauthFetch(TOKEN_URL, {
     method: "POST",
     headers: { "Content-Type": "application/x-www-form-urlencoded" },
     body: new URLSearchParams({
@@ -115,7 +114,6 @@ export async function refreshAntigravity(refreshToken: string, projectId: string
       grant_type: "refresh_token",
     }),
   });
-  const text = await response.text();
   if (!response.ok) throw httpFailure(`Antigravity token refresh failed: ${response.status} ${text}`, response, text);
   const json = JSON.parse(text) as { access_token?: unknown; refresh_token?: unknown; expires_in?: unknown };
   if (typeof json.access_token !== "string" || typeof json.expires_in !== "number") {
@@ -135,9 +133,9 @@ export const antigravityFlow: OAuthFlow = {
       callbacks.onAuth({ url: buildAuthorizeUrl(challenge, verifier), instructions: "Complete the Google sign-in in your browser." });
       const result = await server.waitForCode();
       if (result.state !== verifier) throw new Error("OAuth state mismatch.");
-      const tokens = await exchangeCode(result.code, verifier, clientSecret);
+      const tokens = await exchangeCode(result.code, verifier, clientSecret, callbacks.signal);
       callbacks.onProgress?.("Resolving project");
-      const projectId = await discoverProject(tokens.access);
+      const projectId = await discoverProject(tokens.access, callbacks.signal);
       return { access: tokens.access, refresh: tokens.refresh, expires: tokens.expires, projectId };
     } finally {
       server.close();
diff --git a/src/main/services/oauth/kimi-code-flow.ts b/src/main/services/oauth/kimi-code-flow.ts
index d8d8cc53..5f646946 100644
--- a/src/main/services/oauth/kimi-code-flow.ts
+++ b/src/main/services/oauth/kimi-code-flow.ts
@@ -9,6 +9,7 @@ import { createHash } from "node:crypto";
 import { hostname, platform as osPlatform, release as osRelease, userInfo } from "node:os";
 import type { OAuthCredentials, OAuthFlow, OAuthLoginCallbacks } from "./oauth-types";
 import { httpFailure } from "../provider-http";
+import { oauthFetch } from "./oauth-fetch";
 
 // Published public client id of the official Kimi CLI; reused by third-party
 // coding agents per Kimi's device-flow integration guidance.
@@ -48,8 +49,8 @@ function deviceHeaders(): Record<string, string> {
   };
 }
 
-async function postForm(path: string, form: Record<string, string>): Promise<{ status: number; data: Record<string, unknown>; response: Response; text: string }> {
-  const response = await fetch(`${OAUTH_HOST}${path}`, {
+async function postForm(path: string, form: Record<string, string>, cancel?: AbortSignal): Promise<{ status: number; data: Record<string, unknown>; response: Response; text: string }> {
+  const { response, text } = await oauthFetch(`${OAUTH_HOST}${path}`, {
     method: "POST",
     headers: {
       Accept: "application/json",
@@ -57,8 +58,7 @@ async function postForm(path: string, form: Record<string, string>): Promise<{ s
       ...deviceHeaders(),
     },
     body: new URLSearchParams(form),
-  });
-  const text = await response.text();
+  }, cancel);
   let data: unknown;
   try {
     data = JSON.parse(text);
@@ -79,8 +79,8 @@ interface DeviceAuthorization {
   interval: number;
 }
 
-async function requestDeviceAuthorization(): Promise<DeviceAuthorization> {
-  const { status, data } = await postForm("/api/oauth/device_authorization", { client_id: CLIENT_ID });
+async function requestDeviceAuthorization(cancel?: AbortSignal): Promise<DeviceAuthorization> {
+  const { status, data } = await postForm("/api/oauth/device_authorization", { client_id: CLIENT_ID }, cancel);
   if (status !== 200) throw new Error(`Kimi device authorization failed: ${status} ${JSON.stringify(data)}`);
   const deviceCode = data.device_code;
   const userCode = data.user_code;
@@ -157,7 +157,7 @@ async function pollForToken(device: DeviceAuthorization, signal?: AbortSignal):
       client_id: CLIENT_ID,
       device_code: device.device_code,
       grant_type: "urn:ietf:params:oauth:grant-type:device_code",
-    });
+    }, signal);
     const decision = interpretKimiPollResponse(status, data);
     if (decision.kind === "token") return decision.credentials;
     if (decision.kind === "expired") throw new Error("Kimi device code expired. Please try signing in again.");
@@ -180,7 +180,7 @@ export async function refreshKimiCode(refreshToken: string): Promise<OAuthCreden
 export const kimiCodeFlow: OAuthFlow = {
   providerKey: "kimi-code",
   async login(callbacks: OAuthLoginCallbacks): Promise<OAuthCredentials> {
-    const device = await requestDeviceAuthorization();
+    const device = await requestDeviceAuthorization(callbacks.signal);
     callbacks.onAuth({
       url: device.verification_uri_complete,
       instructions: `Approve code ${device.user_code} in your browser to link your Kimi plan.`,
diff --git a/src/main/services/oauth/oauth-fetch.ts b/src/main/services/oauth/oauth-fetch.ts
new file mode 100644
index 00000000..f91bd87c
--- /dev/null
+++ b/src/main/services/oauth/oauth-fetch.ts
@@ -0,0 +1,24 @@
+import { ProviderHttpError } from "../provider-http";
+
+/** How long one sign-in or renewal request may take, body included. */
+export const OAUTH_REQUEST_TIMEOUT_MS = 30_000;
+
+/** A sign-in or renewal request that ends on the user's cancel or a stalled server; runs stop only their own wait, since refreshes are shared. */
+export async function oauthFetch(url: string, init: RequestInit, cancel?: AbortSignal): Promise<{ response: Response; text: string }> {
+  const controller = new AbortController();
+  const abort = () => controller.abort();
+  if (cancel?.aborted) controller.abort();
+  else cancel?.addEventListener("abort", abort, { once: true });
+  const timer = setTimeout(abort, OAUTH_REQUEST_TIMEOUT_MS);
+  try {
+    const response = await fetch(url, { ...init, signal: controller.signal });
+    return { response, text: await response.text() };
+  } catch (error) {
+    if (cancel?.aborted) throw new Error("Login cancelled");
+    if (controller.signal.aborted) throw new ProviderHttpError(`Sign-in request to ${new URL(url).host} timed out.`, null, null, true);
+    throw error;
+  } finally {
+    clearTimeout(timer);
+    cancel?.removeEventListener("abort", abort);
+  }
+}
diff --git a/src/main/services/oauth/openai-codex-flow.ts b/src/main/services/oauth/openai-codex-flow.ts
index 7335b6e5..5875ab31 100644
--- a/src/main/services/oauth/openai-codex-flow.ts
+++ b/src/main/services/oauth/openai-codex-flow.ts
@@ -8,6 +8,7 @@ import { startOAuthCallbackServer } from "./oauth-callback-server";
 import { generatePkce } from "./pkce";
 import type { OAuthCredentials, OAuthFlow, OAuthLoginCallbacks } from "./oauth-types";
 import { httpFailure } from "../provider-http";
+import { oauthFetch } from "./oauth-fetch";
 
 const CLIENT_ID = "app_EMoamEEZ73f0CkXaXp7hrann";
 const AUTHORIZE_URL = "https://auth.openai.com/oauth/authorize";
@@ -54,8 +55,8 @@ export function extractAccountId(accessToken: string): string | null {
   return null;
 }
 
-async function exchangeCode(code: string, verifier: string): Promise<{ access: string; refresh: string; expires: number }> {
-  const response = await fetch(TOKEN_URL, {
+async function exchangeCode(code: string, verifier: string, cancel?: AbortSignal): Promise<{ access: string; refresh: string; expires: number }> {
+  const { response, text } = await oauthFetch(TOKEN_URL, {
     method: "POST",
     headers: { "Content-Type": "application/x-www-form-urlencoded" },
     body: new URLSearchParams({
@@ -65,12 +66,9 @@ async function exchangeCode(code: string, verifier: string): Promise<{ access: s
       code_verifier: verifier,
       redirect_uri: REDIRECT_URI,
     }),
-  });
-  if (!response.ok) {
-    const text = await response.text().catch(() => "");
-    throw new Error(`Token exchange failed: ${response.status} ${text}`);
-  }
-  const json = (await response.json()) as { access_token?: unknown; refresh_token?: unknown; expires_in?: unknown };
+  }, cancel);
+  if (!response.ok) throw new Error(`Token exchange failed: ${response.status} ${text}`);
+  const json = JSON.parse(text) as { access_token?: unknown; refresh_token?: unknown; expires_in?: unknown };
   if (typeof json.access_token !== "string" || typeof json.refresh_token !== "string" || typeof json.expires_in !== "number") {
     throw new Error("Token response was missing required fields.");
   }
@@ -79,12 +77,11 @@ async function exchangeCode(code: string, verifier: string): Promise<{ access: s
 
 /** Refresh an expired Codex access token using the long-lived refresh token. */
 export async function refreshCodex(refreshToken: string): Promise<OAuthCredentials> {
-  const response = await fetch(TOKEN_URL, {
+  const { response, text } = await oauthFetch(TOKEN_URL, {
     method: "POST",
     headers: { "Content-Type": "application/x-www-form-urlencoded" },
     body: new URLSearchParams({ grant_type: "refresh_token", refresh_token: refreshToken, client_id: CLIENT_ID }),
   });
-  const text = await response.text();
   if (!response.ok) throw httpFailure(`Codex token refresh failed: ${response.status} ${text}`, response, text);
   const json = JSON.parse(text) as { access_token?: unknown; refresh_token?: unknown; expires_in?: unknown };
   if (typeof json.access_token !== "string" || typeof json.refresh_token !== "string" || typeof json.expires_in !== "number") {
@@ -105,7 +102,7 @@ export const openaiCodexFlow: OAuthFlow = {
       callbacks.onAuth({ url: buildAuthorizeUrl(challenge, state), instructions: "Complete the ChatGPT sign-in in your browser." });
       const result = await server.waitForCode();
       if (result.state !== state) throw new Error("OAuth state mismatch.");
-      const tokens = await exchangeCode(result.code, verifier);
+      const tokens = await exchangeCode(result.code, verifier, callbacks.signal);
       const accountId = extractAccountId(tokens.access);
       if (!accountId) throw new Error("Could not read the ChatGPT account id from the token.");
       return { access: tokens.access, refresh: tokens.refresh, expires: tokens.expires, accountId };
diff --git a/src/main/services/provider-tool-turns/credential-resolver.ts b/src/main/services/provider-tool-turns/credential-resolver.ts
index 468dfd6c..77aa3698 100644
--- a/src/main/services/provider-tool-turns/credential-resolver.ts
+++ b/src/main/services/provider-tool-turns/credential-resolver.ts
@@ -31,6 +31,7 @@ import type { IntegrationKeyStore } from "../integration-key-store";
 import { refreshGitHubCopilotToken } from "../oauth/github-copilot-flow";
 import { refreshKimiCode } from "../oauth/kimi-code-flow";
 import { parseStoredOAuth, type StoredOAuth } from "../oauth/stored-oauth";
+import { untilStopped } from "../run-control";
 
 function refreshOAuth(providerKey: string, creds: StoredOAuth, keys: IntegrationKeyStore): Promise<OAuthCredentials> {
   switch (providerKey) {
@@ -101,7 +102,8 @@ export async function resolveTurnCredential(deps: {
   }
   const creds = parseStoredOAuth(deps.provider.provider_key, secret);
   if (Date.now() < creds.expires) return toTurnCredential(creds);
-  return toTurnCredential(await refreshOnce(deps, creds));
+  // Stopping this run ends its own wait; the shared refresh carries on for the other runs.
+  return toTurnCredential(await untilStopped(refreshOnce(deps, creds)));
 }
 
 /** Refreshes in flight, by stored credential: a rotating provider honours a refresh token once, so callers at once share one. */
diff --git a/src/main/services/provider-tool-turns/gcp-auth.ts b/src/main/services/provider-tool-turns/gcp-auth.ts
index a4f4cc79..4b2db7da 100644
--- a/src/main/services/provider-tool-turns/gcp-auth.ts
+++ b/src/main/services/provider-tool-turns/gcp-auth.ts
@@ -5,6 +5,7 @@
  */
 import { createSign } from "node:crypto";
 import { httpFailure } from "../provider-http";
+import { oauthFetch } from "../oauth/oauth-fetch";
 
 interface ServiceAccount {
   client_email: string;
@@ -43,12 +44,11 @@ export async function getGcpAccessToken(serviceAccountJson: string): Promise<str
   const signature = base64url(createSign("RSA-SHA256").update(signingInput).sign(account.private_key));
   const assertion = `${signingInput}.${signature}`;
 
-  const response = await fetch("https://oauth2.googleapis.com/token", {
+  const { response, text } = await oauthFetch("https://oauth2.googleapis.com/token", {
     method: "POST",
     headers: { "Content-Type": "application/x-www-form-urlencoded" },
     body: new URLSearchParams({ grant_type: "urn:ietf:params:oauth:grant-type:jwt-bearer", assertion }),
   });
-  const text = await response.text();
   if (!response.ok) throw httpFailure(`Vertex authentication failed: ${response.status} ${text}`, response, text);
   const json = JSON.parse(text) as { access_token?: unknown; expires_in?: unknown };
   if (typeof json.access_token !== "string" || typeof json.expires_in !== "number") {
diff --git a/tests/unit/credential-refresh-race.test.ts b/tests/unit/credential-refresh-race.test.ts
index 25b8afbf..f65dccd5 100644
--- a/tests/unit/credential-refresh-race.test.ts
+++ b/tests/unit/credential-refresh-race.test.ts
@@ -10,6 +10,7 @@ import { AuthBrokerService } from "../../src/main/services/auth-broker-service";
 import { IntegrationKeyStore } from "../../src/main/services/integration-key-store";
 import { loadConfiguredProvider } from "../../src/main/services/provider-internal";
 import { resolveTurnCredential } from "../../src/main/services/provider-tool-turns/credential-resolver";
+import { stopRun, withRunControl } from "../../src/main/services/run-control";
 
 const vault = { encryptSecret: (secret: string) => Buffer.from(secret, "utf8"), decryptSecret: (ciphertext: Buffer) => ciphertext.toString("utf8") };
 
@@ -57,6 +58,18 @@ describe("an expired sign-in is refreshed once, however many runs need it", () =
     h.connection.close();
   });
 
+  test("stopping one run ends its wait on the shared refresh; the other run still gets the new sign-in", async () => {
+    const calls = rotatingTokenEndpoint();
+    const h = expiredClaudePro();
+    const stopped = withRunControl("run-stopped", () => h.resolve(), 60_000);
+    const other = withRunControl("run-other", () => h.resolve(), 60_000);
+    stopRun("run-stopped", "Stopped by the operator.");
+    await expect(stopped).rejects.toThrow("Stopped by the operator.");
+    expect((await other).accessToken).toBe("access-1");
+    expect(calls).toEqual(["refresh-0"]);
+    h.connection.close();
+  });
+
   test("a run that comes after the refresh uses the stored new sign-in", async () => {
     const calls = rotatingTokenEndpoint();
     const h = expiredClaudePro();
diff --git a/tests/unit/oauth-fetch.test.ts b/tests/unit/oauth-fetch.test.ts
new file mode 100644
index 00000000..9bead6ee
--- /dev/null
+++ b/tests/unit/oauth-fetch.test.ts
@@ -0,0 +1,41 @@
+import { afterEach, describe, expect, test, vi } from "vitest";
+import { oauthFetch, OAUTH_REQUEST_TIMEOUT_MS } from "../../src/main/services/oauth/oauth-fetch";
+import { ProviderHttpError } from "../../src/main/services/provider-http";
+
+/** A server that accepts the connection and never answers, until the request is aborted. */
+function stalledServer(): void {
+  vi.stubGlobal("fetch", (_url: string, init: RequestInit) => new Promise((_resolve, reject) => {
+    init.signal?.addEventListener("abort", () => reject(new DOMException("aborted", "AbortError")), { once: true });
+  }));
+}
+
+afterEach(() => {
+  vi.unstubAllGlobals();
+  vi.useRealTimers();
+});
+
+describe("sign-in and renewal requests end when they should", () => {
+  test("cancelling a sign-in ends the wait on a stalled token exchange", async () => {
+    stalledServer();
+    const cancel = new AbortController();
+    const pending = oauthFetch("https://auth.example.test/token", { method: "POST" }, cancel.signal);
+    cancel.abort();
+    await expect(pending).rejects.toThrow("Login cancelled");
+  });
+
+  test("a stalled exchange or refresh fails as a timeout instead of waiting forever", async () => {
+    vi.useFakeTimers();
+    stalledServer();
+    const pending = oauthFetch("https://auth.example.test/token", { method: "POST" }).catch((error: unknown) => error);
+    await vi.advanceTimersByTimeAsync(OAUTH_REQUEST_TIMEOUT_MS);
+    const failure = await pending;
+    expect(failure).toBeInstanceOf(ProviderHttpError);
+    expect(failure).toMatchObject({ timedOut: true, message: "Sign-in request to auth.example.test timed out." });
+  });
+
+  test("a request that answers returns its status and body", async () => {
+    vi.stubGlobal("fetch", async () => new Response("{\"ok\":true}", { status: 200 }));
+    const { response, text } = await oauthFetch("https://auth.example.test/token", { method: "POST" });
+    expect([response.status, text]).toEqual([200, "{\"ok\":true}"]);
+  });
+});