# Toolweather MCP Server Safety Check

> Toolweather MCP Server Safety Check is a paid API for AI agents from toolweather.toolweather.workers.dev, paid per call via x402, $0.001/call, status unknown (last checked 2026-10-20).

Returns a live safety verdict (safe/caution/unsafe/unknown) for a given MCP server, indicating whether it is healthy and safe to call right now

## Facts

- Endpoint: POST https://toolweather.toolweather.workers.dev/x402/is_safe_to_call?utm_source=zero.xyz
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-20
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/toolweather-mcp-server-safety-check-e1f572c2
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_IH_UDeSo-2TC_PZQzAIdG

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 toolweather-mcp-server-safety-check-e1f572c2 -d '<json body>'
```

Example prompt: Before we proceed, check if the 'brave-search' MCP server is safe to call right now — I don't want to waste time on a broken tool.

## When to prefer this

Use this endpoint when an AI agent or developer workflow needs to confirm that a specific MCP server is healthy before invoking it, especially in automated pipelines where calling a broken server would waste compute or cause cascading failures. It covers ~2,000 official MCP registry servers checked every 15 minutes, making it the most comprehensive pre-call health gate available. Prefer it over generic uptime monitors when you need an MCP-specific safety verdict with actionable recommendations.

## Known failure modes

- HTTP 402 when daily quota exceeded — must pay $0.001 USDC via x402 per call or upgrade key
- HTTP 403 with Cloudflare error code 1010 when using Python urllib default User-Agent — fix by sending any other User-Agent header
- Unknown verdict returned when server has not been checked yet or is not in the ~2,000 monitored registry servers
- Invalid or unresolvable server name/URL returns error or unknown verdict
- Anonymous callers limited to 50 calls/day; key-holders get 1,000/day

## How this service works

Toolweather suite: is this MCP server healthy and safe to call right now? Live health verdicts for ~2,000 public MCP servers from the official registry, checked every 15 minutes, plus working alternatives. The same MCP endpoint also exposes Upstream tools (check_api_status, check_model_deprecation, list_recent_api_changes, list_providers, get_digest) for AI/dev API status and model deprecations; Upstream's own REST/x402 API remains at https://upstream.toolweather.workers.dev. Free tier: 1,000 calls/day per key or 50/day anonymous with no key; get a key instantly with POST /v1/keys (no email or signup). Change alerts: watch up to 3 servers per free key and receive signed HTTPS webhooks. Python urllib users: Cloudflare returns HTTP 403 'error code: 1010' for the default Python-urllib User-Agent; send any other User-Agent header. Pricing: free 1,000 calls/day per key (or 50/day anonymous, no key) and 3 watches; over quota, HTTP 402 x402 v2 exact pay-per-call (USDC on Base): $0.001/check, $0.003/live recheck, $0.01/batch of 25, $0.05 per extra watch per 30 days. No subscription. See /v1/pricing.

## Output

A JSON object containing: a 'verdict' enum ('safe', 'caution', 'unsafe', or 'unknown'), a human-readable 'summary' explaining the verdict, a 'checked_at' ISO timestamp of the last health check (refreshed every 15 minutes), and a 'recommended_action' string advising what to do next.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "server"
 ],
 "properties": {
  "tool": {
   "type": "string",
   "description": "Optional tool name to confirm"
  },
  "server": {
   "type": "string",
   "description": "MCP server registry name or remote URL"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "summary",
  "verdict"
 ],
 "properties": {
  "summary": {
   "type": "string"
  },
  "verdict": {
   "enum": [
    "safe",
    "caution",
    "unsafe",
    "unknown"
   ],
   "type": "string"
  },
  "checked_at": {
   "type": "string"
  },
  "recommended_action": {
   "type": "string"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/toolweather-mcp-server-safety-check-e1f572c2/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from toolweather.toolweather.workers.dev](https://www.zero.xyz/host/toolweather.toolweather.workers.dev/llms.txt)