# 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 relevant endpoints with token-compressed results filtered through a Prompt-Guard firewall.

## Facts

- Endpoint: GET https://prompt-guard.agentdiet.dev/v1/tool-search?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-a0fc85ca
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_iJ8MDLGcfJ_pPAEhc2zfK

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-a0fc85ca
```

Example prompt: Search the MCP and A2A tool index for endpoints that handle SEC filings and company enrichment — I need to find available tools I can route my agent through.

## 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, especially when operating across a large and varied tool ecosystem. Ideal for swarm agents that need to self-route to the right tool at runtime without hardcoding endpoint lists. Prefer this over manual tool registries when token efficiency matters, as the 85% compression reduces LLM context overhead significantly.

## Known failure modes

- Empty query string returns validation error (query is required, minLength 1)
- Query matches no indexed tools — returns empty result set
- Payment not completed (HTTP 402) when x402 micropayment is not provided
- Upstream MCP server index temporarily unavailable — degraded or empty results
- Query too broad returns low-relevance noise across many tools

## 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/v1/tool-search)

## Output

Returns a list of matching MCP servers or A2A tool endpoints relevant to the capability query, with token-compressed descriptions (up to 85% compression) and Prompt-Guard firewall filtering applied. Results include tool names, endpoint references, and capability summaries.

## 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-a0fc85ca/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)