FN-5917: fix Codex OAuth option selection

Prevent multi-option OAuth prompts from cancelling Codex browser login.

- add OAuth option selection logic that prefers the browser flow for openai-codex prompts
- fall back to default-labelled or first options for other multi-option OAuth prompts
- add API route coverage for Codex multi-option, single-option, and generic default-labelled prompt handling

Files changed:
 .changeset/fn-5917-codex-oauth-login.md            |  5 ++
 packages/dashboard/src/__tests__/routes-auth.test.ts    | 72 ++++++++++++++++++++++
 packages/dashboard/src/routes/register-auth-routes.ts   | 26 ++++++--
 3 files changed, 97 insertions(+), 6 deletions(-)

Fusion-Task-Id: FN-5917

Fusion-Task-Lineage: 3b069280-9dbf-47ee-ae04-b7c54ff14d63

.changeset/fn-5917-codex-oauth-login.md

@@ -0,0 +1,5 @@
+---
+"@runfusion/fusion": patch
+---
+
+Fix the dashboard OAuth login flow for ChatGPT Plus/Pro (Codex Subscription) so multi-option provider selection prompts no longer cancel the login before browser auth starts.

packages/dashboard/src/__tests__/routes-auth.test.ts

@@ -1499,6 +1499,78 @@ describe("POST /auth/login", () => {
     expect(observedPromptInput).toBe("manual-code");
   });
 
+  it("prefers browser login for openai-codex multi-option prompts", async () => {
+    let selectedOption: string | undefined;
+    (authStorage.getOAuthProviders as ReturnType<typeof vi.fn>).mockReturnValue([{ id: "openai-codex", name: "OpenAI Codex" }]);
+    (authStorage.login as ReturnType<typeof vi.fn>).mockImplementation(async (_provider: string, callbacks: any) => {
+      selectedOption = await callbacks.onSelect({
+        message: "Select OpenAI Codex login method:",
+        options: [
+          { id: "browser", label: "Browser login (default)" },
+          { id: "device_code", label: "Device code login (headless)" },
+        ],
+      });
+      if (!selectedOption) {
+        throw new Error("Login cancelled");
+      }
+      callbacks.onAuth({
+        url: "https://auth.openai.com/oauth/authorize?state=test-state&redirect_uri=http%3A%2F%2Flocalhost%3A1455%2Fauth%2Fcallback",
+      });
+    });
+
+    const res = await REQUEST(buildApp(), "POST", "/api/auth/login", JSON.stringify({ provider: "openai-codex" }), {
+      "Content-Type": "application/json",
+    });
+
+    expect(selectedOption).toBe("browser");
+    expect(res.status).toBe(200);
+    expect(res.body.url).toBe(
+      "https://auth.openai.com/oauth/authorize?state=test-state&redirect_uri=http%3A%2F%2Flocalhost%3A1455%2Fauth%2Fcallback",
+    );
+  });
+
+  it("keeps returning the only option id for single-option prompts", async () => {
+    let selectedOption: string | undefined;
+    (authStorage.getOAuthProviders as ReturnType<typeof vi.fn>).mockReturnValue([{ id: "openai-codex", name: "OpenAI Codex" }]);
+    (authStorage.login as ReturnType<typeof vi.fn>).mockImplementation(async (_provider: string, callbacks: any) => {
+      selectedOption = await callbacks.onSelect({
+        message: "Only one choice",
+        options: [{ id: "browser", label: "Browser login" }],
+      });
+      callbacks.onAuth({ url: "https://auth.example.com/login" });
+    });
+
+    const res = await REQUEST(buildApp(), "POST", "/api/auth/login", JSON.stringify({ provider: "openai-codex" }), {
+      "Content-Type": "application/json",
+    });
+
+    expect(selectedOption).toBe("browser");
+    expect(res.status).toBe(200);
+  });
+
+  it("prefers the default-labelled option for generic multi-option prompts", async () => {
+    let selectedOption: string | undefined;
+    (authStorage.getOAuthProviders as ReturnType<typeof vi.fn>).mockReturnValue([{ id: "anthropic", name: "Anthropic" }]);
+    (authStorage.login as ReturnType<typeof vi.fn>).mockImplementation(async (_provider: string, callbacks: any) => {
+      selectedOption = await callbacks.onSelect({
+        message: "Select login method:",
+        options: [
+          { id: "device_code", label: "Device code login" },
+          { id: "browser", label: "Browser login (DEFAULT)" },
+          { id: "manual", label: "Manual login" },
+        ],
+      });
+      callbacks.onAuth({ url: "https://claude.ai/oauth/authorize?state=test-state&redirect_uri=http%3A%2F%2Flocalhost%3A3210%2Fauth%2Fcallback" });
+    });
+
+    const res = await REQUEST(buildApp(), "POST", "/api/auth/login", JSON.stringify({ provider: "anthropic" }), {
+      "Content-Type": "application/json",
+    });
+
+    expect(selectedOption).toBe("browser");
+    expect(res.status).toBe(200);
+  });
+
   it("returns 400 when provider is missing", async () => {
     const res = await REQUEST(buildApp(), "POST", "/api/auth/login", JSON.stringify({}), {
       "Content-Type": "application/json",

packages/dashboard/src/routes/register-auth-routes.ts

@@ -189,6 +189,25 @@ export const registerAuthRoutes: ApiRouteRegistrar = (ctx) => {
     return providerId === "github-copilot";
   }
 
+  function selectOauthOption(
+    providerId: string,
+    prompt: { options: Array<{ id: string; label?: string }> },
+  ): string | undefined {
+    if (prompt.options.length === 1) {
+      return prompt.options[0]?.id;
+    }
+
+    const defaultLabeledOption = prompt.options.find((option) => /\(default\)/i.test(option.label ?? ""));
+
+    // FN-5917: returning undefined here caused pi-ai's openai-codex login
+    // flow to throw "Login cancelled" before it could open browser auth.
+    if (providerId === "openai-codex") {
+      return prompt.options.find((option) => option.id === "browser")?.id ?? defaultLabeledOption?.id ?? prompt.options[0]?.id;
+    }
+
+    return defaultLabeledOption?.id ?? prompt.options[0]?.id;
+  }
+
   async function probeDroidCliWithEffectiveBinary(req?: Request) {
     let pluginSettings: Record<string, unknown> | undefined;
     if (req) {
@@ -866,12 +885,7 @@ export const registerAuthRoutes: ApiRouteRegistrar = (ctx) => {
         // to race pasted codes against the localhost callback server.
         onManualCodeInput: async () => await pendingLogin.inputPromise,
         onProgress: () => {}, // no-op for web UI
-        onSelect: async (prompt) => {
-          if (prompt.options.length === 1) {
-            return prompt.options[0]?.id;
-          }
-          return undefined;
-        },
+        onSelect: async (prompt) => selectOauthOption(provider, prompt),
         signal: abortController.signal,
       });