# 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 2026-10-23).

Searches and routes across 500+ indexed MCP servers and A2A tools with token compression and prompt-injection firewall protection

## Facts

- Endpoint: POST https://prompt-guard.agentdiet.dev/v1/b2b-osint-dag?utm_source=zero.xyz
- Price: $0.01/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-23
- 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-1c1929db
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_YeYUuNFGAxQozledPcOB2

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-1c1929db -d '<json body>'
```

Example prompt: Search the A2A and MCP tool index for any available endpoints that handle 'company enrichment' or 'B2B lead data' so I can find the right tool to call next.

## When to prefer this

Choose this endpoint when an AI agent needs to dynamically discover which tool or MCP server to call for a given capability at runtime, rather than having tool routes hardcoded. Especially useful in swarm architectures where agents must self-select the right downstream capability, or when you want a single connection point with built-in prompt-injection protection and token compression across 500+ indexed tools.

## Known failure modes

- Empty query string returns validation error
- No matching tools found for obscure capability queries
- Upstream MCP server unavailable causing partial result set
- Prompt injection attempt blocked by Prompt-Guard firewall returning a security rejection
- Rate limit exceeded on high-frequency discovery requests
- Malformed endpoint URL input returns parsing error

## 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/b2b-osint-dag)

## Output

Returns a compressed, structured list of matching MCP servers or A2A tools relevant to the query, including endpoint metadata, capability descriptions, and routing information — all filtered through a Prompt-Guard firewall to block injection attacks.

## 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-1c1929db/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)