# 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 serp-extract.agentdiet.dev, paid per call via MPP, $0.01/call, status unknown (last checked 2026-10-21).

Searches and discovers MCP servers and A2A agent tools by capability query, routing requests through a token-compressed safe-proxy with prompt injection firewall

## Facts

- Endpoint: GET https://serp-extract.agentdiet.dev/v1/b2a-router?utm_source=zero.xyz
- Price: $0.01/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-21
- Activations on Zero: 0
- Provider: serp-extract.agentdiet.dev
- Website: https://serp-extract.agentdiet.dev
- Canonical page: https://www.zero.xyz/c/serp-extract-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-26df0e5b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap__y33ibBqxLeXOUWQ4uLYE

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 serp-extract-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-26df0e5b
```

Example prompt: Search the MCP and A2A tool index for any servers or agents that can handle 'SEC filings' — I want to find the best available capability and get a token-compressed summary of what each tool does.

## When to prefer this

Choose this endpoint when you need to dynamically discover which MCP servers or A2A agent tools exist for a given capability, especially in multi-agent swarm architectures where you want a single connection point with prompt injection protection and token-efficient responses. Prefer this over manual tool registries when you need to search across 500+ indexed tools simultaneously or verify a specific endpoint's compliance and availability.

## Known failure modes

- Empty query string returns validation error
- No matching tools found for niche query returns empty results
- Endpoint URL verification fails if target is offline or non-compliant
- Token budget exhausted for very broad queries
- Rate limiting or payment failure via x402 if USDC balance insufficient

## 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://serp-extract.agentdiet.dev/v1/b2a-router)

## Output

Returns a token-compressed list of matching MCP servers or A2A tools relevant to the capability query, including tool metadata, endpoint URLs, and verification status — filtered through a Prompt-Guard firewall to prevent injection attacks. Response is an object with discovered tool listings.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "query"
 ],
 "properties": {
  "limit": {
   "type": "integer",
   "default": 20,
   "maximum": 100,
   "minimum": 1,
   "description": "Maximum number of items to return per page (1-100)"
  },
  "query": {
   "type": "string",
   "minLength": 1,
   "description": "Capability search query (e.g. 'context compression', 'github security', 'sec filings', 'company enrichment') or endpoint URL to verify"
  },
  "cursor": {
   "type": "string",
   "description": "Opaque pagination cursor for fetching the next page"
  }
 }
}
```

## Response schema (JSON Schema)

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

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/serp-extract-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-26df0e5b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from serp-extract.agentdiet.dev](https://www.zero.xyz/host/serp-extract.agentdiet.dev/llms.txt)