h3-mcp
MCP servers, built on H3

Lightweight Model Context Protocol server utilities for H3. Dual-era, zero MCP SDK dependency.

import { H3, serve } from "h3"
import { defineMcpHandler, defineMcpTool } from "h3-mcp"

const app = new H3().all("/mcp", defineMcpHandler({
  name: "my-server",
  version: "1.0.0",
  tools: [
    defineMcpTool({
      name: "hello",
      handler: () => ({ content: [{ type: "text", text: "⚡️ Tadaa!" }] }),
    }),
  ],
}))

serve(app)

No SDK Dependency
MCP as a self-contained JSON-RPC 2.0 layer on top of H3. ~34kb min / ~11kb gzip, or ~19kb for a single era.
Dual-Era by Default
One endpoint serves both the stateless 2026-07-28 revision and the initialize-based revisions (≤2025-11-25). Narrow it per request or drop an era from your bundle.
Secure by Default
Origin checks, body-size and content-type limits, boundary input validation, and private cache scopes are on before you configure anything.

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h3-mcpMCP servers, built on H3

Features

No SDK Dependency

Dual-Era by Default

Secure by Default

Sponsors

h3-mcp
MCP servers, built on H3