# Agent Watch Probe

> Agent Watch Probe is a paid API for AI agents from aiagentscity.com, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-22).

Performs a real MCP initialize handshake against an agent/MCP endpoint to check liveness, measure latency, count tools, and detect auth requirements and price challenges.

## Facts

- Endpoint: POST https://aiagentscity.com/api/x402/agent-watch/probe?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-22
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agent-watch-probe-be70416a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_WHCxpB_Kfgyw0mLyzf-7w

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability agent-watch-probe-be70416a -d '<json body>'
```

Example prompt: Can you probe the MCP endpoint at https://myagent.example.com/mcp and tell me if it's alive, how fast it responds, how many tools it exposes, and whether it requires auth or a payment challenge?

## When to prefer this

Use this endpoint when you need a definitive liveness and capability snapshot of an MCP or AI agent endpoint using a real protocol handshake rather than a simple HTTP ping. It is the right choice when you need to know tool count, auth requirements, or x402 price-challenge behavior — not just whether a TCP port is open.

## Known failure modes

- Endpoint unreachable or DNS failure — returns dead/liveness=false with timeout details
- Endpoint responds but does not speak MCP protocol — handshake fails with protocol error
- Price challenge issued unexpectedly — may block probe completion and returns challenge metadata
- Auth token required to complete handshake — probe returns partial metadata with auth requirement flag
- High latency endpoints may timeout before handshake completes

## How this service works

Probe an MCP/agent endpoint: liveness, latency, tool count, auth metadata, price-challenge detection. Real MCP initialize handshake, not a ping.

## Output

Returns liveness status (alive/dead), measured round-trip latency, number of tools advertised by the endpoint, authentication metadata, and whether the endpoint issued a price-challenge (x402 payment required response) — all derived from a real MCP initialize handshake, not a simple ping.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agent-watch-probe-be70416a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from aiagentscity.com](https://www.zero.xyz/host/aiagentscity.com/llms.txt)