---
title: "Paid: MCP Tool Discovery"
method: POST
path: "/api/x402/mcp-tool-catalog"
---

# Paid: MCP Tool Discovery

`POST /api/x402/mcp-tool-catalog`

## Request

- Base URL: `https://three.ws`
- URL: `https://three.ws/api/x402/mcp-tool-catalog`
- Auth: none required

three.ws MCP Tool Discovery — pay $0.001 USDC to discover MCP tools that were registered (or whose price/shape changed, or that were removed) on the three.ws MCP server since you last probed. Returns the diff against a durable tool registry so agents can feature-flag new capabilities the moment they ship instead of re-fetching and diffing tools/list themselves.

## Request body

- object
  - `mode` 'discover' | 'sync' | 'list'

## Response `200`

three.ws MCP Tool Discovery result JSON

## Other responses

- `400`: Validation error
- `402`: Payment Required (x402)

---

[API](https://skmtc.dev/three/apis/three-ws-api.md) · [All operations](https://skmtc.dev/three/apis/three-ws-api/llms.txt) · [OpenAPI document](https://skmtc.dev/three/apis/three-ws-api/revisions/dbc5e3a81b79?raw)