# Universal A2A & MCP Tool Discovery, Safe-Proxy & Swarm Router

> Universal A2A & MCP Tool Discovery, Safe-Proxy & Swarm Router is a paid API for AI agents from x402-audit.agentdiet.dev, paid per call via MPP, $0.01/call, status unknown (last checked 2026-10-21).

Searches an index of 500+ MCP servers and A2A tools by capability query, returning matching endpoints with token-compressed results through a prompt-firewall-protected meta-router.

## Facts

- Endpoint: GET https://x402-audit.agentdiet.dev/v1/universal-mcp-gateway?utm_source=zero.xyz
- Price: $0.01/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-21
- Activations on Zero: 0
- Provider: x402-audit.agentdiet.dev
- Website: https://x402-audit.agentdiet.dev
- Canonical page: https://www.zero.xyz/c/x402-audit-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-proxy-ed29928d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_iihycZEGgyZNwvC4XgJrf

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 x402-audit-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-proxy-ed29928d
```

Example prompt: Search the MCP and A2A tool index for any endpoints that can do GitHub security auditing — give me the best matches with their capabilities and connection details.

## When to prefer this

Choose this endpoint when you need to discover MCP servers or A2A agent tools by capability without manually cataloging hundreds of endpoints. It is especially useful for agent orchestrators, swarm routers, or pipeline builders that need to dynamically resolve which downstream tool handles a given task, and when token budget is a concern due to its 85% compression. Prefer this over manually querying individual MCP registries when breadth of coverage and prompt safety are both priorities.

## Known failure modes

- Empty query string returns validation error
- Query too generic may return low-relevance results across unrelated tools
- Payment not completed (HTTP 402) blocks result delivery
- Prompt-Guard firewall may flag or reject queries containing injection-like patterns
- Index may not reflect newly added MCP servers in real time

## How this service works

Single-connection meta-router indexing 500+ MCP servers & A2A tools with 85% token compression and Prompt-Guard firewall. (Live x402 v2, IETF MPP & MCP endpoint at https://x402-audit.agentdiet.dev/v1/universal-mcp-gateway)

## Output

Returns a list of matching MCP servers or A2A tools from a 500+ endpoint index, with capability descriptions compressed by up to 85% for token efficiency, filtered through a Prompt-Guard firewall to block malicious prompt injection. Results include endpoint metadata, connection details, and relevance to the query.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "query"
 ],
 "properties": {
  "query": {
   "type": "string",
   "minLength": 1,
   "description": "Capability search query (e.g. 'context compression', 'github security', 'sec filings', 'company enrichment') or endpoint URL to verify"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-audit-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-proxy-ed29928d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-audit.agentdiet.dev](https://www.zero.xyz/host/x402-audit.agentdiet.dev/llms.txt)