@mcpc/core


Build agentic MCP servers by composing existing MCP tools.

The core SDK for creating agentic Model Context Protocol (MCP) servers. Compose
existing MCP tools into powerful AI agents with simple descriptions and tool
references.

Installation

``bash


npm (from npm registry)

npm install @mcpc-tech/core

npm (from jsr)

npx jsr add @mcpc/core

deno

deno add jsr:@mcpc/core

pnpm (from npm registry)

pnpm add @mcpc-tech/core

pnpm (from jsr)

pnpm add jsr:@mcpc/core
`

Quick Start

`typescript
import { mcpc } from "@mcpc/core";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";

// Create an agentic MCP server
const server = await mcpc(
[
{ name: "my-agent", version: "1.0.0" },
{ capabilities: { tools: {} } },
],
[{
name: "my-agent",
description:
I am a coding assistant that can read files and run terminal commands.

Available tools:


,
deps: {
mcpServers: {
"desktop-commander": {
command: "npx",
args: ["-y", "@wonderwhy-er/desktop-commander@latest"],
transportType: "stdio",
},
},
},
options: { mode: "agentic" },
}],
);

// Connect to stdio transport
await server.connect(new StdioServerTransport());
`

Key Concepts

$3

Reference tools in your agent description using XML-like syntax:

`typescript
description:
Available tools:
// Basic reference
// All tools from server
// Limit result size
// Hide from public interface
// Expose at global scope
;
`

$3

Support all MCP transport types:

`typescript
deps: {
mcpServers: {
"stdio-server": {
command: "npx",
args: ["-y", "some-mcp-server"],
transportType: "stdio"
},
"http-server": {
transportType: "streamable-http",
url: "https://api.example.com/mcp/",
headers: { "Authorization": "Bearer ${TOKEN}" }
},
"sse-server": {
transportType: "sse",
url: "https://api.example.com/sse/"
}
}
}
`

$3

- agentic (default): Fully autonomous agent without structured workflow
- ai_sampling: Autonomous AI SDK execution
- ai_acp: AI SDK ACP mode for coding agents

$3

Extend functionality with plugins:

`typescript
import { createLargeResultPlugin } from "@mcpc/core/plugins";

{
plugins: [
createLargeResultPlugin({ maxSize: 8000 }),
"./plugins/custom.ts?param=value",
];
}
`

API Reference

$3

Main entry point for creating agentic MCP servers.

Parameters:

- serverConf - Server metadata and capabilities
- composeConf - Array of agent composition definitions (optional)
- setupCallback - Callback for custom setup before composition (optional)

Returns: Promise

See full documentation for detailed usage.

Examples

Find complete examples in the examples/ directory:

- 01-basic-composition.ts - Basic agent composition
- 02-plugin-usage.ts - Using plugins
- 13-ai-sampling-mode.ts - AI SDK sampling mode
- 15-ai-acp-mode.ts` - AI SDK ACP mode

Documentation

- Full Documentation
- Plugin System Guide
- Creating Your First Agentic MCP
- FAQ

License

MIT