Browserbase MCP Server

Instructions

Implementation Reference

• src/tools/session.ts:144-218 (handler)

  The handler function that performs the session close operation: retrieves current session, cleans up via SessionManager, handles errors, resets context to default, and returns appropriate text content with replay URL if available.
  async function handleCloseSession(context: Context): Promise<ToolResult> { const action = async (): Promise<ToolActionResult> => { // Store the current session ID before cleanup const previousSessionId = context.currentSessionId; let cleanupSuccessful = false; let cleanupErrorMessage = ""; // Step 1: Get session info before cleanup let browserbaseSessionId: string | undefined; const sessionManager = context.getSessionManager(); try { const session = await sessionManager.getSession( previousSessionId, context.config, false, ); if (session && session.stagehand) { // Store the actual Browserbase session ID for the replay URL browserbaseSessionId = session.sessionId; // cleanupSession handles both closing Stagehand and cleanup (idempotent) await sessionManager.cleanupSession(previousSessionId); cleanupSuccessful = true; } else { process.stderr.write( `[tool.closeSession] No session found for ID: ${previousSessionId || "default/unknown"}\n`, ); } } catch (error: unknown) { cleanupErrorMessage = error instanceof Error ? error.message : String(error); process.stderr.write( `[tool.closeSession] Error cleaning up session (ID was ${previousSessionId || "default/unknown"}): ${cleanupErrorMessage}\n`, ); } // Step 2: SessionManager automatically resets to default on cleanup // Context.currentSessionId getter will reflect the new active session const oldContextSessionId = previousSessionId; process.stderr.write( `[tool.closeSession] Session context reset to default. Previous context session ID was ${oldContextSessionId || "default/unknown"}.\n`, ); // Step 3: Determine the result message const defaultSessionId = sessionManager.getDefaultSessionId(); if (cleanupErrorMessage && !cleanupSuccessful) { throw new Error( `Failed to cleanup session (session ID was ${previousSessionId || "default/unknown"}). Error: ${cleanupErrorMessage}. Session context has been reset to default.`, ); } if (cleanupSuccessful) { let successMessage = `Browserbase session (${previousSessionId || "default"}) closed successfully. Context reset to default.`; if (browserbaseSessionId && previousSessionId !== defaultSessionId) { successMessage += ` View replay at https://www.browserbase.com/sessions/${browserbaseSessionId}`; } return { content: [{ type: "text", text: successMessage }] }; } // No session was found let infoMessage = "No active session found to close. Session context has been reset to default."; if (previousSessionId && previousSessionId !== defaultSessionId) { infoMessage = `No active session found for session ID '${previousSessionId}'. The context has been reset to default.`; } return { content: [{ type: "text", text: infoMessage }] }; }; return { action: action, waitForNetwork: false, }; }
• src/tools/session.ts:135-142 (schema)

  Zod schema for input (empty object) and tool schema definition including name, description, and inputSchema.
  const CloseSessionInputSchema = z.object({}); const closeSessionSchema: ToolSchema<typeof CloseSessionInputSchema> = { name: "browserbase_session_close", description: "Close the current Browserbase session and reset the active context.", inputSchema: CloseSessionInputSchema, };
• src/tools/session.ts:220-224 (registration)

  Defines the tool object combining schema and handler, and exports it as part of sessionTools array for further registration.
  const closeSessionTool: Tool<typeof CloseSessionInputSchema> = { capability: "core", schema: closeSessionSchema, handle: handleCloseSession, };
• src/tools/index.ts:6-27 (registration)

  Imports sessionTools (containing browserbase_session_close) and includes it in the TOOLS array exported for MCP server registration.
  import sessionTools from "./session.js"; import getUrlTool from "./url.js"; // Export individual tools export { default as navigateTool } from "./navigate.js"; export { default as actTool } from "./act.js"; export { default as extractTool } from "./extract.js"; export { default as observeTool } from "./observe.js"; export { default as screenshotTool } from "./screenshot.js"; export { default as sessionTools } from "./session.js"; export { default as getUrlTool } from "./url.js"; // Export all tools as array export const TOOLS = [ ...sessionTools, navigateTool, actTool, extractTool, observeTool, screenshotTool, getUrlTool, ];
• src/index.ts:186-216 (registration)

  Imports TOOLS, iterates over all tools including browserbase_session_close, and registers each to the MCP server via server.tool(), wrapping the call to context.run(tool, params) which invokes the tool's handle function.
  const tools: MCPToolsArray = [...TOOLS]; // Register each tool with the Smithery server tools.forEach((tool) => { if (tool.schema.inputSchema instanceof z.ZodObject) { server.tool( tool.schema.name, tool.schema.description, tool.schema.inputSchema.shape, async (params: z.infer<typeof tool.schema.inputSchema>) => { try { const result = await context.run(tool, params); return result; } catch (error) { const errorMessage = error instanceof Error ? error.message : String(error); process.stderr.write( `[Smithery Error] ${new Date().toISOString()} Error running tool ${tool.schema.name}: ${errorMessage}\n`, ); throw new Error( `Failed to run tool '${tool.schema.name}': ${errorMessage}`, ); } }, ); } else { console.warn( `Tool "${tool.schema.name}" has an input schema that is not a ZodObject. Schema type: ${tool.schema.inputSchema.constructor.name}`, ); } });