# 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 prompt-guard.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 compressed, firewall-filtered results for agent tool discovery and routing.

## Facts

- Endpoint: GET https://prompt-guard.agentdiet.dev/api/mcp/audit?utm_source=zero.xyz
- Price: $0.01/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-21
- Activations on Zero: 0
- Provider: prompt-guard.agentdiet.dev
- Website: https://prompt-guard.agentdiet.dev
- Canonical page: https://www.zero.xyz/c/prompt-guard-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-62e47359
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_0QYkiabcTu7QTRTZnLJZy

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 prompt-guard-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-62e47359
```

Example prompt: Search the MCP tool index for servers that handle 'SEC filings' — I need to find an available A2A or MCP endpoint my agent can call for that capability.

## When to prefer this

Choose this endpoint when an AI agent needs to dynamically discover which MCP servers or A2A tools are available for a given capability without hardcoding endpoints. It is especially valuable for agent swarms that need safe, token-efficient routing across a large tool ecosystem, or when you want a Prompt-Guard firewall layer between your agent and third-party tools.

## Known failure modes

- Missing or empty 'query' parameter returns validation error
- No matching tools found for the given capability query returns empty result set
- Upstream MCP server index unavailable causes partial or degraded results
- x402 payment not completed results in 402 Payment Required response
- Query too vague returns low-relevance or overly broad matches

## 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://prompt-guard.agentdiet.dev/api/mcp/audit)

## Output

Returns a compressed list of matching MCP servers or A2A tools for the given capability query, including metadata such as tool names, descriptions, endpoint URLs, and firewall/compliance status, with up to 85% token compression applied.

## 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/prompt-guard-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-62e47359/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from prompt-guard.agentdiet.dev](https://www.zero.xyz/host/prompt-guard.agentdiet.dev/llms.txt)