refactor: Update adapter and agent types to use StructuredToolInterface

Author: zandko

src/adapters/langchain_adapter.ts

@@ -1,39 +1,24 @@
 import type { JSONSchema } from '@dmitryrechkin/json-schema-to-zod'
+import type { StructuredToolInterface } from '@langchain/core/tools'
 import type {
   CallToolResult,
   EmbeddedResource,
   ImageContent,
   Tool as McpTool,
   TextContent,
 } from '@modelcontextprotocol/sdk/types.js'
-import type { ZodObject, ZodTypeAny } from 'zod'
+import type { ZodTypeAny } from 'zod'
 import type { BaseConnector } from '../connectors/base.js'
-import { JSONSchemaToZod } from '@dmitryrechkin/json-schema-to-zod'
 
+import { JSONSchemaToZod } from '@dmitryrechkin/json-schema-to-zod'
 import { DynamicStructuredTool } from '@langchain/core/tools'
 import { z } from 'zod'
 import { logger } from '../logging.js'
 import { BaseAdapter } from './base.js'
 
 function schemaToZod(schema: unknown): ZodTypeAny {
-  /** Recursively normalise `type: [T, U]` → `anyOf: [{type:T},{type:U}]`. */
-  // const fixSchema = (s: any): any => {
-  //   if (s && typeof s === 'object') {
-  //     if (Array.isArray(s.type)) {
-  //       s.anyOf = s.type.map((t: any) => ({ type: t }))
-  //       delete s.type
-  //     }
-  //     for (const [k, v] of Object.entries(s)) {
-  //       s[k] = fixSchema(v)
-  //     }
-  //   }
-  //   return s
-  // }
-
   try {
-    // const normalised = fixSchema(structuredClone(schema))
-    const zodSchema = JSONSchemaToZod.convert(schema as JSONSchema)
-    return zodSchema
+    return JSONSchemaToZod.convert(schema as JSONSchema)
   }
   catch (err) {
     logger.warn(`Failed to convert JSON schema to Zod: ${err}`)
@@ -84,7 +69,7 @@ function parseMcpToolResult(toolResult: CallToolResult): string {
   return decoded
 }
 
-export class LangChainAdapter extends BaseAdapter<DynamicStructuredTool> {
+export class LangChainAdapter extends BaseAdapter<StructuredToolInterface> {
   constructor(disallowedTools: string[] = []) {
     super(disallowedTools)
   }
@@ -95,7 +80,7 @@ export class LangChainAdapter extends BaseAdapter<DynamicStructuredTool> {
   protected convertTool(
     mcpTool: McpTool,
     connector: BaseConnector,
-  ): DynamicStructuredTool | null {
+  ): StructuredToolInterface | null {
     // Filter out disallowed tools early.
     if (this.disallowedTools.includes(mcpTool.name)) {
       return null
@@ -121,7 +106,7 @@ export class LangChainAdapter extends BaseAdapter<DynamicStructuredTool> {
           return `Error executing MCP tool: ${String(err)}`
         }
       },
-    }) as DynamicStructuredTool<ZodObject<any>, any>
+    })
 
     return tool
   }

src/agents/mcp_agent.ts

@@ -1,8 +1,8 @@
-import type { BaseLanguageModel, LanguageModelLike } from '@langchain/core/language_models/base'
+import type { BaseLanguageModelInterface, LanguageModelLike } from '@langchain/core/language_models/base'
 import type {
   BaseMessage,
 } from '@langchain/core/messages'
-import type { DynamicStructuredTool } from '@langchain/core/tools'
+import type { StructuredToolInterface } from '@langchain/core/tools'
 import type { AgentFinish, AgentStep } from 'langchain/agents'
 import type { MCPClient } from '../client.js'
 import type { BaseConnector } from '../connectors/base.js'
@@ -28,7 +28,7 @@ import { createSystemMessage } from './prompts/system_prompt_builder.js'
 import { DEFAULT_SYSTEM_PROMPT_TEMPLATE, SERVER_MANAGER_SYSTEM_PROMPT_TEMPLATE } from './prompts/templates.js'
 
 export class MCPAgent {
-  private llm: LanguageModelLike
+  private llm: BaseLanguageModelInterface
   private client?: MCPClient
   private connectors: BaseConnector[]
   private maxSteps: number
@@ -46,12 +46,12 @@ export class MCPAgent {
   private agentExecutor: AgentExecutor | null = null
   private sessions: Record<string, MCPSession> = {}
   private systemMessage: SystemMessage | null = null
-  private tools: DynamicStructuredTool[] = []
+  private tools: StructuredToolInterface[] = []
   private adapter: LangChainAdapter
   private serverManager: ServerManager | null = null
 
   constructor(options: {
-    llm: BaseLanguageModel
+    llm: BaseLanguageModelInterface
     client?: MCPClient
     connectors?: BaseConnector[]
     serverName?: string
@@ -162,7 +162,7 @@ export class MCPAgent {
     logger.info('✨ Agent initialization complete')
   }
 
-  private async createSystemMessageFromTools(tools: DynamicStructuredTool[]): Promise<void> {
+  private async createSystemMessageFromTools(tools: StructuredToolInterface[]): Promise<void> {
     const systemPromptTemplate
       = this.systemPromptTemplateOverride
         ?? DEFAULT_SYSTEM_PROMPT_TEMPLATE
@@ -196,7 +196,7 @@ export class MCPAgent {
     ])
 
     const agent = createToolCallingAgent({
-      llm: this.llm,
+      llm: this.llm as unknown as LanguageModelLike,
       tools: this.tools,
       prompt,
     })
@@ -298,7 +298,7 @@ export class MCPAgent {
       const intermediateSteps: AgentStep[] = []
       const inputs = { input: query, chat_history: langchainHistory } as Record<string, unknown>
 
-      let nameToToolMap: Record<string, DynamicStructuredTool> = Object.fromEntries(this.tools.map(t => [t.name, t]))
+      let nameToToolMap: Record<string, StructuredToolInterface> = Object.fromEntries(this.tools.map(t => [t.name, t]))
       logger.info(`🏁 Starting agent execution with max_steps=${steps}`)
 
       for (let stepNum = 0; stepNum < steps; stepNum++) {

src/agents/prompts/system_prompt_builder.ts

@@ -1,8 +1,8 @@
-import type { DynamicStructuredTool } from '@langchain/core/tools'
+import type { StructuredToolInterface } from '@langchain/core/tools'
 import { SystemMessage } from '@langchain/core/messages'
 
 export function generateToolDescriptions(
-  tools: DynamicStructuredTool[],
+  tools: StructuredToolInterface[],
   disallowedTools?: string[],
 ): string[] {
   const disallowedSet = new Set(disallowedTools ?? [])
@@ -44,7 +44,7 @@ export function buildSystemPromptContent(
 }
 
 export function createSystemMessage(
-  tools: DynamicStructuredTool[],
+  tools: StructuredToolInterface[],
   systemPromptTemplate: string,
   serverManagerTemplate: string,
   useServerManager: boolean,

src/task_managers/sse.ts

@@ -25,7 +25,6 @@ export class SseConnectionManager extends ConnectionManager<SSEClientTransport>
    */
   protected async establishConnection(): Promise<SSEClientTransport> {
     this._transport = new SSEClientTransport(this.url, this.opts)
-    // await this._transport.start()
 
     logger.debug(`${this.constructor.name} connected successfully`)
     return this._transport

src/task_managers/stdio.ts

@@ -29,7 +29,6 @@ export class StdioConnectionManager extends ConnectionManager<StdioClientTranspo
   protected async establishConnection(): Promise<StdioClientTransport> {
     // Instantiate and start the transport
     this._transport = new StdioClientTransport(this.serverParams)
-    // await this._transport.start()
 
     // If stderr was piped, forward it to `errlog` for visibility
     if (this._transport.stderr && typeof (this._transport.stderr as any).pipe === 'function') {