JSON Placeholder Posts MCP

A small UV-managed FastMCP server that calls:

https://json-placeholder.mock.beeceptor.com/posts

It exposes one MCP tool, get_posts_by_user, which supports elicitation. If the caller does not provide userId, the server asks the MCP client/user for it. The tool also emits MCP server notifications with log messages and progress updates while it resolves the user, fetches posts, and filters results.

Setup

uv sync

Related MCP server: JSONPlaceholder MCP Server

Run

For MCP clients that use stdio:

uv run json-placeholder-posts-mcp

For local HTTP testing:

uv run json-placeholder-posts-mcp --transport streamable-http

By default the HTTP server listens at:

http://127.0.0.1:8000/mcp

You can override the host and port with environment variables:

HOST=127.0.0.1 PORT=9000 uv run json-placeholder-posts-mcp --transport streamable-http

Tool

get_posts_by_user

Fetches all posts from the Beeceptor API and returns only posts matching the provided userId.

Input:

{
  "userId": 1
}

If userId is omitted and the MCP client supports elicitation, the server asks:

Enter the userId to fetch posts for.

Output:

{
  "userId": 1,
  "count": 2,
  "posts": [],
  "source": "https://json-placeholder.mock.beeceptor.com/posts"
}

Development

uv run pytest
uv run ruff check .