Test AI agent webhooks & tool-callbacks
When an agent calls a tool or fires a callback, you need to see the real request it sent. Hand it a Catchr URL and read back precisely what it did — headers, auth token, and payload included.
Docs- Agent-native. A bin is created and read with plain HTTP, so an agent can provision and verify its own callbacks — see /llms.txt and /openapi.json.
- Full fidelity. Inspect the exact method, headers (including auth), query and body the agent sent.
- Zero setup. No account, no keys to manage beyond the per-bin token you get on create.
- Recipes ready. Copy-paste pytest / Node / CI snippets to assert on captured calls.
# one call, no signup
curl -s -X POST https://catchr.perch-app.workers.dev/api/bins
# → {"id":"a1b2c3d4","url":"https://catchr.perch-app.workers.dev/h/a1b2c3d4","token":"…"}
# send anything to the url, then read it back:
curl "https://catchr.perch-app.workers.dev/api/bins/a1b2c3d4/requests?token=…"
See copy-paste CI & agent recipes →
Why agents need a request inspector
When an AI agent calls an external tool or fires a callback, the only way to know it did the right thing is to see the actual HTTP request it produced — the endpoint, the auth header, the JSON body. A Catchr bin is a safe target for exactly that: point the agent's tool at the bin URL, let it run, then read back the precise request it sent.
Two ways to wire it up
- As a plain HTTP target. Give the agent a bin URL, then
GET /api/bins/:id/requests?token=…&wait=25to block until the call lands and assert on it — no polling loop. - As an MCP server. Add Catchr's remote MCP endpoint (
/mcp) to Claude, Cursor or any MCP client, and the agent getscreate_bin,get_requestsandset_responsetools so it can provision and verify its own callbacks.
Frequently asked questions
How do I see the exact request an AI agent sends?
Give the agent a Catchr bin URL as its tool or callback target, then read the bin. You get the full method, headers (including auth), query and body it produced, verbatim.
Can an agent create and read a bin by itself?
Yes. Every action is a plain HTTP call, and there is a machine-readable /openapi.json and /llms.txt, so an agent can provision a bin and verify its own callbacks without a human.
Does Catchr support MCP?
Yes. It exposes a remote MCP server at /mcp with create_bin, get_requests (which blocks until a request arrives) and set_response tools for MCP clients like Claude and Cursor.
Can I mock a specific response back to the agent?
Yes. Set a bin's custom status, content-type and body so the agent receives a chosen reply — useful for testing how it handles a 500 or a specific JSON response.
Is it free and signup-free?
Yes. No account is required and there is no paywall.