Add ContextRouter

.changeset/cold-bears-behave.md

@@ -0,0 +1,5 @@
+---
+"agents": patch
+---
+
+Add unstable_getMcpPrompt to provide LLM consumable MCP integration context

packages/agents/src/mcp/client-connection.ts

@@ -2,7 +2,6 @@ import { SSEEdgeClientTransport } from "./sse-edge";
 
 import {
   ToolListChangedNotificationSchema,
-  type ClientCapabilities,
   type Resource,
   type Tool,
   type Prompt,
@@ -14,7 +13,7 @@ import {
   type ServerCapabilities,
   type ResourceTemplate,
   type ListResourceTemplatesResult,
-  type Notification,
+  type Implementation,
 } from "@modelcontextprotocol/sdk/types.js";
 import { Client } from "@modelcontextprotocol/sdk/client/index.js";
 import type { SSEClientTransportOptions } from "@modelcontextprotocol/sdk/client/sse.js";
@@ -34,6 +33,7 @@ export class MCPClientConnection {
   resources: Resource[] = [];
   resourceTemplates: ResourceTemplate[] = [];
   serverCapabilities: ServerCapabilities | undefined;
+  serverInfo: Implementation | undefined;
 
   constructor(
     public url: URL,
@@ -84,20 +84,28 @@ export class MCPClientConnection {
       throw new Error("The MCP Server failed to return server capabilities");
     }
 
-    const [instructions, tools, resources, prompts, resourceTemplates] =
-      await Promise.all([
-        this.client.getInstructions(),
-        this.registerTools(),
-        this.registerResources(),
-        this.registerPrompts(),
-        this.registerResourceTemplates(),
-      ]);
+    const [
+      instructions,
+      serverInfo,
+      tools,
+      resources,
+      prompts,
+      resourceTemplates,
+    ] = await Promise.all([
+      this.client.getInstructions(),
+      this.client.getServerVersion(),
+      this.registerTools(),
+      this.registerResources(),
+      this.registerPrompts(),
+      this.registerResourceTemplates(),
+    ]);
 
     this.instructions = instructions;
     this.tools = tools;
     this.resources = resources;
     this.prompts = prompts;
     this.resourceTemplates = resourceTemplates;
+    this.serverInfo = serverInfo;
 
     this.connectionState = "ready";
   }

packages/agents/src/mcp/client-prompt.ts

@@ -0,0 +1,34 @@
+import type { MCPClientConnection } from "./client-connection";
+import type { Resource } from "@modelcontextprotocol/sdk/types.js";
+
+export function unstable_getMcpPrompt(
+  conns: Record<string, MCPClientConnection>,
+  includeResources: boolean
+) {
+  return `<integrations_list>
+        You have access to multiple integrations via Model Context Protocol (MCP). These integrations provide you with tools which you can use to execute to complete tasks or retrieive information.
+
+        ${includeResources && "Each integration, provides a list of resources, which are included in the list of integrations below."}
+
+        Here is a list of all of the integrations you have access to, with instructions if necessary:
+        
+        ${Object.entries(conns).map(([_id, conn]) => serverContext(conn, includeResources))}
+    <integrations_list>`;
+}
+
+function serverContext(conn: MCPClientConnection, includeResources: boolean) {
+  return `<integration>
+        ${conn.serverInfo && `<integration_name>${conn.serverInfo.name}</integration_name>`}
+        ${conn.instructions && `<integration_instructions>${conn.instructions}</integration_instructions>`}
+        ${includeResources && `<resources_list>${conn.resources.map((resource) => resourceContext(resource))}</resources_list>`}
+    <integration>`;
+}
+
+function resourceContext(resource: Resource) {
+  return `<resource>
+        <name>${resource.name}</name>
+        <uri>${resource.uri}</uri>
+        <description>${resource.description}</description>
+        <mimeType>${resource.mimeType}</mimeType>
+    </resource>`;
+}

packages/agents/src/mcp/client.ts

@@ -17,6 +17,7 @@ import type { RequestOptions } from "@modelcontextprotocol/sdk/shared/protocol.j
 import type { AgentsOAuthProvider } from "./do-oauth-client-provider";
 import { jsonSchema, type ToolSet } from "ai";
 import { nanoid } from "nanoid";
+import { unstable_getMcpPrompt } from "./client-prompt";
 
 /**
  * Utility class that aggregates multiple MCP clients into one
@@ -301,6 +302,15 @@ export class MCPClientManager {
       options
     );
   }
+
+  /**
+   * Utility function to fetch MCP information which you can add to an LLM's system prompt.
+   *
+   * @param includeResources Whether to include resources in the prompt. This may be useful if you include a tool to fetch resources OR if the servers you connect to interact with resources.
+   */
+  unstable_getMcpPrompt(includeResources = true): string {
+    return unstable_getMcpPrompt(this.mcpConnections, includeResources);
+  }
 }
 
 type NamespacedData = {