agentsearch-mcp

A remote MCP (Model Context Protocol) connector for AgentSearch API — an LLM/MCP-native web toolkit for agents and RAG pipelines: web search (provider-abstracted SERP), keyless instant answers, and URL → clean text/markdown fetch ready for an LLM context window.

Live: https://agentsearch-mcp.vercel.app/mcp — 3 tools, one per AgentSearch /v1 endpoint. Since the upstream AgentSearch deployment is metered (RapidAPI/Apify) and gates /v1/* behind a RapidAPI proxy-secret guard, this connector authenticates its own outbound calls with that same secret (AGENTSEARCH_MCP_PROXY_SECRET, sent as the X-RapidAPI-Proxy-Secret header) and applies a soft per-IP rate limit (AGENTSEARCH_MCP_RATE_LIMIT, default 30 tool-calls/hour, in-memory) so the free MCP tier stays a discovery channel rather than an unmetered bypass of the paid listing — see lib/ratelimit.js.

What this is, and why it's a separate connector

AgentSearch API is a plain REST API. Any HTTP client can already call it directly. This repo exists because MCP clients (Claude, ChatGPT, and other MCP-aware agents) don't consume arbitrary REST APIs — they consume MCP tools. agentsearch-mcp is a thin adapter layer that:

• Exposes each AgentSearch endpoint as a discoverable, typed MCP tool (name, description, zod input schema, annotations) that an LLM can reason about and call directly, instead of having to be taught the REST surface out-of-band.
• Speaks the MCP streamable-HTTP transport at a single /mcp endpoint, so it can be registered as a connector in Claude, ChatGPT, or any other MCP client with one URL.
• Does nothing else. It has no business logic of its own — every tool call is a pass-through fetch to AgentSearch, and the JSON response AgentSearch returns is handed back verbatim as the tool result.

Free discovery tier over a metered API

This connector is a free discovery/growth tier in front of the metered AgentSearch API. The upstream (agentsearch-api.vercel.app) is sold on RapidAPI/Apify; this MCP wrapper authenticates to it with the shared RapidAPI proxy secret and caps usage per-IP so it stays a taste-test rather than an unmetered path around the paid plans. Heavy/production volume should go through AgentSearch on RapidAPI/Apify.

Authentication: None on the MCP side (deliberate)

AgentSearch's data has no per-user dimension — it's public web data (SERP results, DuckDuckGo instant answers, cleaned page text). There is nothing to gate per-caller, so this connector intentionally ships with:

• No OAuth, no login, no bearer tokens for the MCP caller
• No Supabase / database
• No demo-vs-real account split — every caller gets the same real, live data

api/mcp.js builds a fresh, stateless McpServer per request and serves it with zero MCP-caller auth checks. The only outbound auth is the upstream RapidAPI proxy secret described above, which the connector holds server-side.

Tool list

One tool per AgentSearch /v1 endpoint (from agentsearch-api/openapi.yaml; /api/health is intentionally not wrapped):

Tool	AgentSearch endpoint	Description
web_search	GET /v1/search	Web SERP via a provider-abstracted backend (Brave or Serper). Returns normalized results with position/title/url/snippet/domain.
instant_answer	GET /v1/answer	Keyless DuckDuckGo instant answer — definitions, entities, quick facts.
fetch_url	GET /v1/fetch	Keyless, SSRF-guarded URL → clean, boilerplate-free text or markdown for RAG.

All 3 tools are read-only and annotated { readOnlyHint: true, destructiveHint: false, idempotentHint: true, openWorldHint: true } — none of them write anything, and all of them reflect live, externally-changing web data.

How it wraps agentsearch-api

Each tool handler does a plain fetch(\${AGENTSEARCH_MCP_API_BASE_URL}${path}`, ...)` against the real AgentSearch REST API and returns the parsed JSON as MCP tool-result content:

{ content: [{ type: 'text', text: JSON.stringify(result, null, 2) }] }

The outbound request carries X-RapidAPI-Proxy-Secret: <AGENTSEARCH_MCP_PROXY_SECRET> so it passes the upstream guard on /v1/*. Upstream HTTP errors (4xx/5xx) are caught and surfaced as a typed MCP error result via an asError helper rather than crashing the request.

Environment variables

Var	Default	Purpose
AGENTSEARCH_MCP_API_BASE_URL	https://agentsearch-api.vercel.app	Upstream AgentSearch base URL (override for local/self-hosted testing).
AGENTSEARCH_MCP_PROXY_SECRET	(empty)	RapidAPI proxy secret, sent as X-RapidAPI-Proxy-Secret to pass the upstream /v1/* guard. Without it, guarded routes return 403.
AGENTSEARCH_MCP_RATE_LIMIT	30	Soft per-IP tools/call cap per hour (in-memory, per serverless instance).

Project layout

api/mcp.js       MCP endpoint (StreamableHTTPServerTransport, stateless, no MCP-caller auth)
api/health.js    GET /api/health
lib/tools.js     All 3 tool definitions (zod schemas + fetch-and-forward handlers, proxy-secret auth)
lib/ratelimit.js Soft per-IP tools/call rate limiter
local-server.js  Plain-Node http server for local dev / smoke testing (not deployed)
test/smoke.mjs   Real end-to-end smoke test (initialize, tools/list, tools/call)
vercel.json      Routes /mcp -> api/mcp.js, /health -> api/health.js
server.json      MCP registry manifest

Local development

npm install
npm run dev          # starts local-server.js on :3900
npm run smoke        # runs test/smoke.mjs against the local server

To exercise a real end-to-end fetch through the upstream guard, set the proxy secret first:

export AGENTSEARCH_MCP_PROXY_SECRET=<the RapidAPI proxy secret>
npm run dev &
npm run smoke