fix(web): auth gate Ask APIs for Public SaaS

CHANGELOG.md

@@ -7,6 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+- Require authentication for the streaming and blocking Ask APIs in Public SaaS deployments. [#1679](https://github.com/sourcebot-dev/sourcebot/pull/1679)
+
 ## [5.1.14] - 2026-09-17
 
 ### Added

packages/web/src/app/api/(server)/ee/chat/route.ts

@@ -12,6 +12,7 @@ import { getAISDKLanguageModelAndOptions } from "@/features/chat/llm.server";
 import { resolveContextWindow } from "@/features/chat/modelContextWindow.server";
 import { materializeCommandMessageTexts } from "@/ee/features/chat/skills/commandResolution";
 import { getAskSkillAvailabilityAnalytics, getAskSkillTurnCompletedAnalytics } from "@/ee/features/chat/skills/skillAnalytics.server";
+import { checkAskAuthentication } from "@/features/chat/askAuth";
 import { apiHandler } from "@/lib/apiHandler";
 import { ErrorCode } from "@/lib/errorCodes";
 import { captureEvent } from "@/lib/posthog";
@@ -50,6 +51,11 @@ export const POST = apiHandler(async (req: NextRequest) => {
 
     const response = await sew(() =>
         withOptionalAuth(async ({ org, user, prisma }) => {
+            const authError = checkAskAuthentication(user);
+            if (authError) {
+                return authError;
+            }
+
             // Gate the generative path behind the `ask` entitlement. The client
             // also gates this, but server-side enforcement can't be bypassed.
             const askError = await checkAskEntitlement();

packages/web/src/app/api/(server)/ee/mcp/route.ts

@@ -2,9 +2,10 @@ import { WebStandardStreamableHTTPServerTransport } from '@modelcontextprotocol/
 import { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js';
 import { createMcpServer } from '@/ee/features/mcp/server';
 import { MCP_PAID_PLAN_REQUIRED_MESSAGE } from '@/ee/features/mcp/constants';
+import { checkAskAuthentication } from '@/features/chat/askAuth';
 import { withOptionalAuth } from '@/middleware/withAuth';
 import { isServiceError } from '@/lib/utils';
-import { notAuthenticated, serviceErrorResponse, ServiceError } from '@/lib/serviceError';
+import { serviceErrorResponse, ServiceError } from '@/lib/serviceError';
 import { ErrorCode } from '@/lib/errorCodes';
 import { StatusCodes } from 'http-status-codes';
 import { NextRequest } from 'next/server';
@@ -85,8 +86,9 @@ export const POST = apiHandler(async (request: NextRequest) => {
 
     const response = await sew(() =>
         withOptionalAuth(async ({ user, principal }) => {
-            if (env.EXPERIMENT_ASK_GH_ENABLED === 'true' && !user) {
-                return notAuthenticated();
+            const authError = checkAskAuthentication(user);
+            if (authError) {
+                return authError;
             }
             const ownerId = user?.id ?? null;
             const sessionId = request.headers.get(MCP_SESSION_ID_HEADER);
@@ -151,8 +153,9 @@ export const DELETE = apiHandler(async (request: NextRequest) => {
 
     const result = await sew(() =>
         withOptionalAuth(async ({ user }) => {
-            if (env.EXPERIMENT_ASK_GH_ENABLED === 'true' && !user) {
-                return notAuthenticated();
+            const authError = checkAskAuthentication(user);
+            if (authError) {
+                return authError;
             }
             const ownerId = user?.id ?? null;
             const sessionId = request.headers.get(MCP_SESSION_ID_HEADER);

packages/web/src/ee/features/mcp/askCodebase.ts

@@ -4,6 +4,7 @@ import { generateChatNameFromMessage } from "@/ee/features/chat/llm.server";
 import { getAISDKLanguageModelAndOptions } from "@/features/chat/llm.server";
 import { resolveContextWindow } from "@/features/chat/modelContextWindow.server";
 import { LanguageModelInfo, SBChatMessage, SearchScope } from "@/features/chat/types";
+import { checkAskAuthentication } from "@/features/chat/askAuth";
 import { convertLLMOutputToPortableMarkdown, getAnswerPartFromAssistantMessage, getLanguageModelKey } from "@/features/chat/utils";
 import { resolveModelCapabilities } from "@/features/chat/modelCapabilities.server";
 import { ErrorCode } from "@/lib/errorCodes";
@@ -49,6 +50,11 @@ const blockStreamUntilFinish = async <T extends UIMessage<unknown, UIDataTypes,
 export const askCodebase = (params: AskCodebaseParams): Promise<AskCodebaseResult | ServiceError> =>
     sew(() =>
         withOptionalAuth(async ({ org, user, prisma }) => {
+            const authError = checkAskAuthentication(user);
+            if (authError) {
+                return authError;
+            }
+
             // Ask Sourcebot is a paid feature. askCodebase() is the single choke point
             // for the programmatic ask path (the MCP `ask_codebase` tool and the
             // /api/chat/blocking route both wrap it), so gating here covers both without

packages/web/src/features/chat/askAuth.test.ts

@@ -0,0 +1,39 @@
+import { beforeEach, describe, expect, test, vi } from "vitest";
+
+const mocks = vi.hoisted(() => ({
+    env: {
+        EXPERIMENT_ASK_GH_ENABLED: "false",
+    },
+}));
+
+vi.mock("@sourcebot/shared", () => ({
+    env: mocks.env,
+}));
+
+const { checkAskAuthentication } = await import("./askAuth");
+
+beforeEach(() => {
+    mocks.env.EXPERIMENT_ASK_GH_ENABLED = "false";
+});
+
+describe("checkAskAuthentication", () => {
+    test("rejects anonymous Ask requests when Public SaaS is enabled", () => {
+        mocks.env.EXPERIMENT_ASK_GH_ENABLED = "true";
+
+        expect(checkAskAuthentication(undefined)).toEqual({
+            statusCode: 401,
+            errorCode: "NOT_AUTHENTICATED",
+            message: "Not authenticated",
+        });
+    });
+
+    test("allows authenticated Ask requests when Public SaaS is enabled", () => {
+        mocks.env.EXPERIMENT_ASK_GH_ENABLED = "true";
+
+        expect(checkAskAuthentication({ id: "user-1" })).toBeNull();
+    });
+
+    test("allows anonymous Ask requests when Public SaaS is disabled", () => {
+        expect(checkAskAuthentication(undefined)).toBeNull();
+    });
+});

packages/web/src/features/chat/askAuth.ts

@@ -0,0 +1,14 @@
+import { notAuthenticated, type ServiceError } from "@/lib/serviceError";
+import { env } from "@sourcebot/shared";
+
+/**
+ * Public SaaS requires an authenticated user for Ask requests. Self-hosted
+ * deployments retain their existing anonymous-access behavior.
+ */
+export const checkAskAuthentication = (user: object | undefined): ServiceError | null => {
+    if (env.EXPERIMENT_ASK_GH_ENABLED === "true" && !user) {
+        return notAuthenticated();
+    }
+
+    return null;
+};