🔐 fix: MCP OAuth Tool Discovery and Event Emission (#11599)

* fix: MCP OAuth tool discovery and event emission in event-driven mode

- Add discoverServerTools method to MCPManager for tool discovery when OAuth is required
- Fix OAuth event emission to send both ON_RUN_STEP and ON_RUN_STEP_DELTA events
- Fix hasSubscriber flag reset in GenerationJobManager for proper event buffering
- Add ToolDiscoveryOptions and ToolDiscoveryResult types
- Update reinitMCPServer to use new discovery method and propagate OAuth URLs

* refactor: Update ToolService and MCP modules for improved functionality

- Reintroduced Constants in ToolService for better reference management.
- Enhanced loadToolDefinitionsWrapper to handle both response and streamId scenarios.
- Updated MCP module to correct type definitions for oauthStart parameter.
- Improved MCPConnectionFactory to ensure proper disconnection handling during tool discovery.
- Adjusted tests to reflect changes in mock implementations and ensure accurate behavior during OAuth handling.

* fix: Refine OAuth handling in MCPConnectionFactory and related tests

- Updated the OAuth URL assignment logic in reinitMCPServer to prevent overwriting existing URLs.
- Enhanced error logging to provide clearer messages when tool discovery fails.
- Adjusted tests to reflect changes in OAuth handling, ensuring accurate detection of OAuth requirements without generating URLs in discovery mode.

* refactor: Clean up OAuth URL assignment in reinitMCPServer

- Removed redundant OAuth URL assignment logic in the reinitMCPServer function to streamline the tool discovery process.
- Enhanced error logging for tool discovery failures, improving clarity in debugging and monitoring.

* fix: Update response handling in ToolService for event-driven mode

- Changed the condition in loadToolDefinitionsWrapper to check for writableEnded instead of headersSent, ensuring proper event emission when the response is still writable.
- This adjustment enhances the reliability of event handling during tool execution, particularly in streaming scenarios.

packages/api/src/mcp/MCPConnectionFactory.ts

@@ -1,5 +1,6 @@
 import { logger } from '@librechat/data-schemas';
 import type { OAuthClientInformation } from '@modelcontextprotocol/sdk/shared/auth.js';
+import type { Tool } from '@modelcontextprotocol/sdk/types.js';
 import type { TokenMethods } from '@librechat/data-schemas';
 import type { MCPOAuthTokens, OAuthMetadata } from '~/mcp/oauth';
 import type { FlowStateManager } from '~/flow/manager';
@@ -11,6 +12,13 @@ import { withTimeout } from '~/utils/promise';
 import { MCPConnection } from './connection';
 import { processMCPEnv } from '~/utils';
 
+export interface ToolDiscoveryResult {
+  tools: Tool[] | null;
+  connection: MCPConnection | null;
+  oauthRequired: boolean;
+  oauthUrl: string | null;
+}
+
 /**
  * Factory for creating MCP connections with optional OAuth authentication.
  * Handles OAuth flows, token management, and connection retry logic.
@@ -41,6 +49,137 @@ export class MCPConnectionFactory {
     return factory.createConnection();
   }
 
+  /**
+   * Discovers tools from an MCP server, even when OAuth is required.
+   * Per MCP spec, tool listing should be possible without authentication.
+   * Returns tools if discoverable, plus OAuth status for tool execution.
+   */
+  static async discoverTools(
+    basic: t.BasicConnectionOptions,
+    oauth?: Omit<t.OAuthConnectionOptions, 'returnOnOAuth'>,
+  ): Promise<ToolDiscoveryResult> {
+    const factory = new this(basic, oauth ? { ...oauth, returnOnOAuth: true } : undefined);
+    return factory.discoverToolsInternal();
+  }
+
+  protected async discoverToolsInternal(): Promise<ToolDiscoveryResult> {
+    const oauthUrl: string | null = null;
+    let oauthRequired = false;
+
+    const oauthTokens = this.useOAuth ? await this.getOAuthTokens() : null;
+    const connection = new MCPConnection({
+      serverName: this.serverName,
+      serverConfig: this.serverConfig,
+      userId: this.userId,
+      oauthTokens,
+    });
+
+    const oauthHandler = async () => {
+      logger.info(
+        `${this.logPrefix} [Discovery] OAuth required; skipping URL generation in discovery mode`,
+      );
+      oauthRequired = true;
+      connection.emit('oauthFailed', new Error('OAuth required during tool discovery'));
+    };
+
+    if (this.useOAuth) {
+      connection.on('oauthRequired', oauthHandler);
+    }
+
+    try {
+      const connectTimeout = this.connectionTimeout ?? this.serverConfig.initTimeout ?? 30000;
+      await withTimeout(
+        connection.connect(),
+        connectTimeout,
+        `Connection timeout after ${connectTimeout}ms`,
+      );
+
+      if (await connection.isConnected()) {
+        const tools = await connection.fetchTools();
+        if (this.useOAuth) {
+          connection.removeListener('oauthRequired', oauthHandler);
+        }
+        return { tools, connection, oauthRequired: false, oauthUrl: null };
+      }
+    } catch {
+      logger.debug(
+        `${this.logPrefix} [Discovery] Connection failed, attempting unauthenticated tool listing`,
+      );
+    }
+
+    try {
+      const tools = await this.attemptUnauthenticatedToolListing();
+      if (this.useOAuth) {
+        connection.removeListener('oauthRequired', oauthHandler);
+      }
+      if (tools && tools.length > 0) {
+        logger.info(
+          `${this.logPrefix} [Discovery] Successfully discovered ${tools.length} tools without auth`,
+        );
+        try {
+          await connection.disconnect();
+        } catch {
+          // Ignore cleanup errors
+        }
+        return { tools, connection: null, oauthRequired, oauthUrl };
+      }
+    } catch (listError) {
+      logger.debug(`${this.logPrefix} [Discovery] Unauthenticated tool listing failed:`, listError);
+    }
+
+    if (this.useOAuth) {
+      connection.removeListener('oauthRequired', oauthHandler);
+    }
+
+    try {
+      await connection.disconnect();
+    } catch {
+      // Ignore cleanup errors
+    }
+
+    return { tools: null, connection: null, oauthRequired, oauthUrl };
+  }
+
+  protected async attemptUnauthenticatedToolListing(): Promise<Tool[] | null> {
+    const unauthConnection = new MCPConnection({
+      serverName: this.serverName,
+      serverConfig: this.serverConfig,
+      userId: this.userId,
+      oauthTokens: null,
+    });
+
+    unauthConnection.on('oauthRequired', () => {
+      logger.debug(
+        `${this.logPrefix} [Discovery] Unauthenticated connection requires OAuth, failing fast`,
+      );
+      unauthConnection.emit(
+        'oauthFailed',
+        new Error('OAuth not supported in unauthenticated discovery'),
+      );
+    });
+
+    try {
+      const connectTimeout = this.connectionTimeout ?? this.serverConfig.initTimeout ?? 15000;
+      await withTimeout(unauthConnection.connect(), connectTimeout, `Unauth connection timeout`);
+
+      if (await unauthConnection.isConnected()) {
+        const tools = await unauthConnection.fetchTools();
+        await unauthConnection.disconnect();
+        return tools;
+      }
+    } catch {
+      logger.debug(`${this.logPrefix} [Discovery] Unauthenticated connection attempt failed`);
+    }
+
+    try {
+      await unauthConnection.disconnect();
+    } catch {
+      // Ignore cleanup errors
+    }
+
+    return null;
+  }
+
   protected constructor(basic: t.BasicConnectionOptions, oauth?: t.OAuthConnectionOptions) {
     this.serverConfig = processMCPEnv({
       options: basic.serverConfig,
@@ -56,7 +195,7 @@ export class MCPConnectionFactory {
       : `[MCP][${basic.serverName}]`;
 
     if (oauth?.useOAuth) {
-      this.userId = oauth.user.id;
+      this.userId = oauth.user?.id;
       this.flowManager = oauth.flowManager;
       this.tokenMethods = oauth.tokenMethods;
       this.signal = oauth.signal;

packages/api/src/mcp/MCPManager.ts

@@ -8,11 +8,12 @@ import type { FlowStateManager } from '~/flow/manager';
 import type { MCPOAuthTokens } from './oauth';
 import type { RequestBody } from '~/types';
 import type * as t from './types';
+import { MCPServersInitializer } from './registry/MCPServersInitializer';
+import { MCPServerInspector } from './registry/MCPServerInspector';
+import { MCPServersRegistry } from './registry/MCPServersRegistry';
 import { UserConnectionManager } from './UserConnectionManager';
 import { ConnectionsRepository } from './ConnectionsRepository';
-import { MCPServerInspector } from './registry/MCPServerInspector';
-import { MCPServersInitializer } from './registry/MCPServersInitializer';
-import { MCPServersRegistry } from './registry/MCPServersRegistry';
+import { MCPConnectionFactory } from './MCPConnectionFactory';
 import { preProcessGraphTokens } from '~/utils/graph';
 import { formatToolContent } from './parsers';
 import { MCPConnection } from './connection';
@@ -68,6 +69,70 @@ export class MCPManager extends UserConnectionManager {
     }
   }
 
+  /**
+   * Discovers tools from an MCP server, even when OAuth is required.
+   * Per MCP spec, tool listing should be possible without authentication.
+   * Use this for agent initialization to get tool schemas before OAuth flow.
+   */
+  public async discoverServerTools(args: t.ToolDiscoveryOptions): Promise<t.ToolDiscoveryResult> {
+    const { serverName, user } = args;
+    const logPrefix = user?.id ? `[MCP][User: ${user.id}][${serverName}]` : `[MCP][${serverName}]`;
+
+    try {
+      const existingAppConnection = await this.appConnections?.get(serverName);
+      if (existingAppConnection && (await existingAppConnection.isConnected())) {
+        const tools = await existingAppConnection.fetchTools();
+        return { tools, oauthRequired: false, oauthUrl: null };
+      }
+    } catch {
+      logger.debug(`${logPrefix} [Discovery] App connection not available, trying discovery mode`);
+    }
+
+    const serverConfig = (await MCPServersRegistry.getInstance().getServerConfig(
+      serverName,
+      user?.id,
+    )) as t.MCPOptions | null;
+
+    if (!serverConfig) {
+      logger.warn(`${logPrefix} [Discovery] Server config not found`);
+      return { tools: null, oauthRequired: false, oauthUrl: null };
+    }
+
+    const useOAuth = Boolean(
+      serverConfig.requiresOAuth || (serverConfig as t.ParsedServerConfig).oauthMetadata,
+    );
+
+    const basic: t.BasicConnectionOptions = { serverName, serverConfig };
+
+    if (!useOAuth) {
+      const result = await MCPConnectionFactory.discoverTools(basic);
+      return {
+        tools: result.tools,
+        oauthRequired: result.oauthRequired,
+        oauthUrl: result.oauthUrl,
+      };
+    }
+
+    if (!user || !args.flowManager) {
+      logger.warn(`${logPrefix} [Discovery] OAuth server requires user and flowManager`);
+      return { tools: null, oauthRequired: true, oauthUrl: null };
+    }
+
+    const result = await MCPConnectionFactory.discoverTools(basic, {
+      user,
+      useOAuth: true,
+      flowManager: args.flowManager,
+      tokenMethods: args.tokenMethods,
+      signal: args.signal,
+      oauthStart: args.oauthStart,
+      customUserVars: args.customUserVars,
+      requestBody: args.requestBody,
+      connectionTimeout: args.connectionTimeout,
+    });
+
+    return { tools: result.tools, oauthRequired: result.oauthRequired, oauthUrl: result.oauthUrl };
+  }
+
   /** Returns all available tool functions from app-level connections */
   public async getAppToolFunctions(): Promise<t.LCAvailableTools> {
     const toolFunctions: t.LCAvailableTools = {};

packages/api/src/mcp/UserConnectionManager.ts

@@ -49,7 +49,7 @@ export abstract class UserConnectionManager {
     serverName: string;
     forceNew?: boolean;
   } & Omit<t.OAuthConnectionOptions, 'useOAuth'>): Promise<MCPConnection> {
-    const userId = user.id;
+    const userId = user?.id;
     if (!userId) {
       throw new McpError(ErrorCode.InvalidRequest, `[MCP] User object missing id property`);
     }

packages/api/src/mcp/__tests__/MCPConnectionFactory.test.ts

@@ -1,6 +1,5 @@
 import { logger } from '@librechat/data-schemas';
-import type { TokenMethods } from '@librechat/data-schemas';
-import type { TUser } from 'librechat-data-provider';
+import type { TokenMethods, IUser } from '@librechat/data-schemas';
 import type { FlowStateManager } from '~/flow/manager';
 import type { MCPOAuthTokens } from '~/mcp/oauth';
 import type * as t from '~/mcp/types';
@@ -27,7 +26,7 @@ const mockMCPConnection = MCPConnection as jest.MockedClass<typeof MCPConnection
 const mockMCPOAuthHandler = MCPOAuthHandler as jest.Mocked<typeof MCPOAuthHandler>;
 
 describe('MCPConnectionFactory', () => {
-  let mockUser: TUser;
+  let mockUser: IUser | undefined;
   let mockServerConfig: t.MCPOptions;
   let mockFlowManager: jest.Mocked<FlowStateManager<MCPOAuthTokens | null>>;
   let mockConnectionInstance: jest.Mocked<MCPConnection>;
@@ -37,7 +36,7 @@ describe('MCPConnectionFactory', () => {
     mockUser = {
       id: 'user123',
       email: 'test@example.com',
-    } as TUser;
+    } as IUser;
 
     mockServerConfig = {
       command: 'node',
@@ -275,7 +274,7 @@ describe('MCPConnectionFactory', () => {
         user: mockUser,
       };
 
-      const oauthOptions = {
+      const oauthOptions: t.OAuthConnectionOptions = {
         user: mockUser,
         useOAuth: true,
         returnOnOAuth: true,
@@ -424,4 +423,116 @@ describe('MCPConnectionFactory', () => {
       );
     });
   });
+
+  describe('discoverTools static method', () => {
+    const mockTools = [
+      { name: 'tool1', description: 'First tool', inputSchema: { type: 'object' } },
+      { name: 'tool2', description: 'Second tool', inputSchema: { type: 'object' } },
+    ];
+
+    it('should discover tools from a successfully connected server', async () => {
+      const basicOptions = {
+        serverName: 'test-server',
+        serverConfig: mockServerConfig,
+      };
+
+      mockConnectionInstance.connect.mockResolvedValue(undefined);
+      mockConnectionInstance.isConnected.mockResolvedValue(true);
+      mockConnectionInstance.fetchTools = jest.fn().mockResolvedValue(mockTools);
+
+      const result = await MCPConnectionFactory.discoverTools(basicOptions);
+
+      expect(result.tools).toEqual(mockTools);
+      expect(result.oauthRequired).toBe(false);
+      expect(result.oauthUrl).toBeNull();
+      expect(result.connection).toBe(mockConnectionInstance);
+    });
+
+    it('should detect OAuth required without generating URL in discovery mode', async () => {
+      const basicOptions = {
+        serverName: 'test-server',
+        serverConfig: {
+          ...mockServerConfig,
+          url: 'https://api.example.com',
+          type: 'sse' as const,
+        } as t.SSEOptions,
+      };
+
+      const mockOAuthStart = jest.fn().mockResolvedValue(undefined);
+
+      const oauthOptions = {
+        useOAuth: true as const,
+        user: mockUser as unknown as IUser,
+        flowManager: mockFlowManager,
+        oauthStart: mockOAuthStart,
+        tokenMethods: {
+          findToken: jest.fn(),
+          createToken: jest.fn(),
+          updateToken: jest.fn(),
+          deleteTokens: jest.fn(),
+        },
+      };
+
+      mockConnectionInstance.isConnected.mockResolvedValue(false);
+      mockConnectionInstance.disconnect = jest.fn().mockResolvedValue(undefined);
+
+      let oauthHandler: (() => Promise<void>) | undefined;
+      mockConnectionInstance.on.mockImplementation((event, handler) => {
+        if (event === 'oauthRequired') {
+          oauthHandler = handler as () => Promise<void>;
+        }
+        return mockConnectionInstance;
+      });
+
+      mockConnectionInstance.connect.mockImplementation(async () => {
+        if (oauthHandler) {
+          await oauthHandler();
+        }
+        throw new Error('OAuth required');
+      });
+
+      const result = await MCPConnectionFactory.discoverTools(basicOptions, oauthOptions);
+
+      expect(result.connection).toBeNull();
+      expect(result.tools).toBeNull();
+      expect(result.oauthRequired).toBe(true);
+      expect(result.oauthUrl).toBeNull();
+      expect(mockOAuthStart).not.toHaveBeenCalled();
+    });
+
+    it('should return null tools when discovery fails completely', async () => {
+      const basicOptions = {
+        serverName: 'test-server',
+        serverConfig: mockServerConfig,
+      };
+
+      mockConnectionInstance.connect.mockRejectedValue(new Error('Connection failed'));
+      mockConnectionInstance.isConnected.mockResolvedValue(false);
+      mockConnectionInstance.disconnect = jest.fn().mockResolvedValue(undefined);
+
+      const result = await MCPConnectionFactory.discoverTools(basicOptions);
+
+      expect(result.tools).toBeNull();
+      expect(result.connection).toBeNull();
+      expect(result.oauthRequired).toBe(false);
+    });
+
+    it('should handle disconnect errors gracefully during cleanup', async () => {
+      const basicOptions = {
+        serverName: 'test-server',
+        serverConfig: mockServerConfig,
+      };
+
+      mockConnectionInstance.connect.mockRejectedValue(new Error('Connection failed'));
+      mockConnectionInstance.isConnected.mockResolvedValue(false);
+      mockConnectionInstance.disconnect = jest
+        .fn()
+        .mockRejectedValue(new Error('Disconnect failed'));
+
+      const result = await MCPConnectionFactory.discoverTools(basicOptions);
+
+      expect(result.tools).toBeNull();
+      expect(mockLogger.debug).toHaveBeenCalled();
+    });
+  });
 });

packages/api/src/mcp/__tests__/MCPManager.test.ts

@@ -4,6 +4,7 @@ import type { GraphTokenResolver } from '~/utils/graph';
 import type * as t from '~/mcp/types';
 import { MCPServersInitializer } from '~/mcp/registry/MCPServersInitializer';
 import { MCPServerInspector } from '~/mcp/registry/MCPServerInspector';
+import { MCPConnectionFactory } from '~/mcp/MCPConnectionFactory';
 import { ConnectionsRepository } from '~/mcp/ConnectionsRepository';
 import { MCPConnection } from '~/mcp/connection';
 import { MCPManager } from '~/mcp/MCPManager';
@@ -48,6 +49,7 @@ jest.mock('~/mcp/registry/MCPServersInitializer', () => ({
 
 jest.mock('~/mcp/registry/MCPServerInspector');
 jest.mock('~/mcp/ConnectionsRepository');
+jest.mock('~/mcp/MCPConnectionFactory');
 
 const mockLogger = logger as jest.Mocked<typeof logger>;
 
@@ -787,4 +789,139 @@ describe('MCPManager', () => {
       );
     });
   });
+
+  describe('discoverServerTools', () => {
+    const mockTools = [
+      { name: 'tool1', description: 'First tool', inputSchema: { type: 'object' } },
+      { name: 'tool2', description: 'Second tool', inputSchema: { type: 'object' } },
+    ];
+
+    const mockConnection = {
+      isConnected: jest.fn().mockResolvedValue(true),
+      fetchTools: jest.fn().mockResolvedValue(mockTools),
+    } as unknown as MCPConnection;
+
+    beforeEach(() => {
+      (MCPConnectionFactory.discoverTools as jest.Mock) = jest.fn();
+    });
+
+    it('should return tools from existing app connection when available', async () => {
+      mockAppConnections({
+        get: jest.fn().mockResolvedValue(mockConnection),
+      });
+
+      const manager = await MCPManager.createInstance(newMCPServersConfig());
+      const result = await manager.discoverServerTools({ serverName });
+
+      expect(result.tools).toEqual(mockTools);
+      expect(result.oauthRequired).toBe(false);
+      expect(result.oauthUrl).toBeNull();
+      expect(MCPConnectionFactory.discoverTools).not.toHaveBeenCalled();
+    });
+
+    it('should use MCPConnectionFactory.discoverTools when no app connection available', async () => {
+      mockAppConnections({
+        get: jest.fn().mockResolvedValue(null),
+      });
+
+      (mockRegistryInstance.getServerConfig as jest.Mock).mockResolvedValue({
+        type: 'stdio',
+        command: 'test',
+        args: [],
+      });
+
+      (MCPConnectionFactory.discoverTools as jest.Mock).mockResolvedValue({
+        tools: mockTools,
+        connection: null,
+        oauthRequired: false,
+        oauthUrl: null,
+      });
+
+      const manager = await MCPManager.createInstance(newMCPServersConfig());
+      const result = await manager.discoverServerTools({ serverName });
+
+      expect(result.tools).toEqual(mockTools);
+      expect(result.oauthRequired).toBe(false);
+      expect(MCPConnectionFactory.discoverTools).toHaveBeenCalled();
+    });
+
+    it('should return null tools when server config not found', async () => {
+      mockAppConnections({
+        get: jest.fn().mockResolvedValue(null),
+      });
+
+      (mockRegistryInstance.getServerConfig as jest.Mock).mockResolvedValue(null);
+
+      const manager = await MCPManager.createInstance(newMCPServersConfig());
+      const result = await manager.discoverServerTools({ serverName });
+
+      expect(result.tools).toBeNull();
+      expect(result.oauthRequired).toBe(false);
+      expect(mockLogger.warn).toHaveBeenCalledWith(
+        expect.stringContaining('Server config not found'),
+      );
+    });
+
+    it('should return OAuth info when server requires OAuth but no user provided', async () => {
+      mockAppConnections({
+        get: jest.fn().mockResolvedValue(null),
+      });
+
+      (mockRegistryInstance.getServerConfig as jest.Mock).mockResolvedValue({
+        type: 'sse',
+        url: 'https://api.example.com',
+        requiresOAuth: true,
+      });
+
+      const manager = await MCPManager.createInstance(newMCPServersConfig());
+      const result = await manager.discoverServerTools({ serverName });
+
+      expect(result.tools).toBeNull();
+      expect(result.oauthRequired).toBe(true);
+      expect(mockLogger.warn).toHaveBeenCalledWith(
+        expect.stringContaining('OAuth server requires user and flowManager'),
+      );
+    });
+
+    it('should discover tools with OAuth when user and flowManager provided', async () => {
+      const mockUser = { id: 'user123', email: 'test@example.com' } as unknown as IUser;
+      const mockFlowManager = {
+        createFlow: jest.fn(),
+        getFlowState: jest.fn(),
+        deleteFlow: jest.fn(),
+      };
+
+      mockAppConnections({
+        get: jest.fn().mockResolvedValue(null),
+      });
+
+      (mockRegistryInstance.getServerConfig as jest.Mock).mockResolvedValue({
+        type: 'sse',
+        url: 'https://api.example.com',
+        requiresOAuth: true,
+      });
+
+      (MCPConnectionFactory.discoverTools as jest.Mock).mockResolvedValue({
+        tools: mockTools,
+        connection: null,
+        oauthRequired: true,
+        oauthUrl: 'https://auth.example.com/authorize',
+      });
+
+      const manager = await MCPManager.createInstance(newMCPServersConfig());
+      const result = await manager.discoverServerTools({
+        serverName,
+        user: mockUser,
+        flowManager: mockFlowManager as unknown as t.ToolDiscoveryOptions['flowManager'],
+      });
+
+      expect(result.tools).toEqual(mockTools);
+      expect(result.oauthRequired).toBe(true);
+      expect(result.oauthUrl).toBe('https://auth.example.com/authorize');
+      expect(MCPConnectionFactory.discoverTools).toHaveBeenCalledWith(
+        expect.objectContaining({ serverName }),
+        expect.objectContaining({ user: mockUser, useOAuth: true }),
+      );
+    });
+  });
 });

packages/api/src/mcp/types/index.ts

@@ -169,7 +169,7 @@ export interface BasicConnectionOptions {
 }
 
 export interface OAuthConnectionOptions {
-  user: IUser;
+  user?: IUser;
   useOAuth: true;
   requestBody?: RequestBody;
   customUserVars?: Record<string, string>;
@@ -181,3 +181,21 @@ export interface OAuthConnectionOptions {
   returnOnOAuth?: boolean;
   connectionTimeout?: number;
 }
+
+export interface ToolDiscoveryOptions {
+  serverName: string;
+  user?: IUser;
+  flowManager?: FlowStateManager<o.MCPOAuthTokens | null>;
+  tokenMethods?: TokenMethods;
+  signal?: AbortSignal;
+  oauthStart?: (authURL: string) => Promise<void>;
+  customUserVars?: Record<string, string>;
+  requestBody?: RequestBody;
+  connectionTimeout?: number;
+}
+
+export interface ToolDiscoveryResult {
+  tools: Tool[] | null;
+  oauthRequired: boolean;
+  oauthUrl: string | null;
+}

packages/api/src/stream/GenerationJobManager.ts

@@ -238,6 +238,7 @@ class GenerationJobManagerClass {
       const currentRuntime = this.runtimeState.get(streamId);
       if (currentRuntime) {
         currentRuntime.syncSent = false;
+        currentRuntime.hasSubscriber = false;
         // Persist syncSent=false to Redis for cross-replica consistency
         this.jobStore.updateJob(streamId, { syncSent: false }).catch((err) => {
           logger.error(`[GenerationJobManager] Failed to persist syncSent=false:`, err);
@@ -435,6 +436,7 @@ class GenerationJobManagerClass {
       const currentRuntime = this.runtimeState.get(streamId);
       if (currentRuntime) {
         currentRuntime.syncSent = false;
+        currentRuntime.hasSubscriber = false;
         // Persist syncSent=false to Redis
         this.jobStore.updateJob(streamId, { syncSent: false }).catch((err) => {
           logger.error(`[GenerationJobManager] Failed to persist syncSent=false:`, err);
@@ -767,7 +769,6 @@ class GenerationJobManagerClass {
         for (const bufferedEvent of runtime.earlyEventBuffer) {
           onChunk(bufferedEvent);
         }
-        // Clear buffer after replay
         runtime.earlyEventBuffer = [];
       }
     }
@@ -822,7 +823,6 @@ class GenerationJobManagerClass {
     // Buffer early events if no subscriber yet (replay when first subscriber connects)
     if (!runtime.hasSubscriber) {
       runtime.earlyEventBuffer.push(event);
-      // Also emit to transport in case subscriber connects mid-flight
     }
 
     this.eventTransport.emitChunk(streamId, event);