# Forest Agent Tools – MCP Contract Check

> Forest Agent Tools – MCP Contract Check is a paid API for AI agents from http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run, paid per call via x402, $0.004/call, status unknown (last checked 2026-10-20).

Inspects a public MCP HTTP endpoint, auto-detects protocol version, and returns a deterministic SHA-256 contract fingerprint of its tools/list schema without invoking any tools

## Facts

- Endpoint: POST https://http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run/mcp/contract-check?utm_source=zero.xyz
- Price: $0.004/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-20
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/forest-agent-tools-mcp-contract-check-afeb4afd
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_fP6aBtZDQzM2C78WjHvA-

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 forest-agent-tools-mcp-contract-check-afeb4afd -d '<json body>'
```

Example prompt: Can you inspect the MCP server at https://myserver.example.com/mcp and give me its SHA-256 contract fingerprint — auto-detect the protocol version?

## When to prefer this

Use this endpoint when you need a cheap, safe, read-only fingerprint of an MCP server's tool contract without risking any side effects from tool invocation. Ideal for change detection pipelines, pre-integration audits, and protocol compatibility checks. Prefer it over manual inspection when you want a deterministic, repeatable hash suitable for diffing across time or deployments.

## Known failure modes

- Target URL is unreachable or returns non-2xx — endpoint reports connection failure
- MCP endpoint does not conform to any recognized protocol version — fingerprint cannot be produced
- URL fails pattern validation (must start with http:// or https://) — request rejected client-side
- Target server requires authentication — Forest cannot inspect gated endpoints
- protocol_version field exceeds 32 characters — request rejected
- MCP server responds with malformed JSON — normalization fails

## How this service works

Machine-readable contract for active Forest paid capabilities. Unsigned paid calls return HTTP 402 with a PAYMENT-REQUIRED x402 challenge.

## Output

Returns a deterministic SHA-256 hash fingerprinting the normalized tools/list schema of the target MCP endpoint, along with the detected protocol version (stateless 2026-07-28 era or legacy initialize lifecycle) and the raw normalized schema. No tools are invoked and no authentication is attempted.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "url": {
   "type": "string",
   "pattern": "^https?://",
   "maxLength": 2048,
   "minLength": 1,
   "description": "Public HTTP(S) URL to inspect, resolve, or compare."
  },
  "protocol_version": {
   "type": "string",
   "maxLength": 32,
   "minLength": 1,
   "description": "Public protocol version value used to scope this lookup."
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "data": {
   "url": "example",
   "scope": "mcp_protocol_discovery_and_tools_schema_contract_only",
   "tools": [],
   "warnings": [],
   "reachable": false,
   "transport": "http-jsonrpc",
   "truncated": false,
   "latency_ms": 0,
   "tool_count": 0,
   "tools_hash": "0000000000000000000000000000000000000000000000000000000000000000",
   "capabilities": [],
   "protocol_era": "modern",
   "schema_valid": false,
   "auth_required": false,
   "protocol_version": "example",
   "invalid_tool_count": 0
  },
  "meta": {
   "cache": "miss",
   "provider": "mcp-contract",
   "checked_at": "2026-01-01T00:00:00.000Z",
   "duration_ms": 0
  },
  "version": "1",
  "capability": "mcp.contract-check"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/forest-agent-tools-mcp-contract-check-afeb4afd/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run](https://www.zero.xyz/host/http--forest-gas-station-mainnet--lcjl27p8lmjs.code.run/llms.txt)