# 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 json-repair.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 tool descriptors via a single meta-router connection.

## Facts

- Endpoint: GET https://json-repair.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: json-repair.agentdiet.dev
- Website: https://json-repair.agentdiet.dev
- Canonical page: https://www.zero.xyz/c/json-repair-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-proxy-d07fc30d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_2HNuIeH9n2fuecenS6RlS

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 json-repair-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-proxy-d07fc30d
```

Example prompt: Search the A2A and MCP tool index for anything that can do 'company enrichment' — I need a compressed list of available tools I can route to for that capability.

## When to prefer this

Choose this endpoint when an AI agent needs to discover and route to the right tool among hundreds of MCP servers or A2A agents without maintaining its own tool registry. It is especially valuable for multi-agent swarms that need token-efficient tool descriptors, or when you want firewall-filtered (Prompt-Guard) safety before connecting to an unfamiliar MCP endpoint. Prefer it over manually curating tool lists or querying individual MCP directories.

## Known failure modes

- Query too vague — returns zero or low-relevance tool matches
- Endpoint URL not found in index — returns empty or not-indexed status
- Prompt injection detected by Prompt-Guard — request blocked with firewall rejection
- Payment not processed (x402) — returns 402 Payment Required before results are served
- Malformed query string — returns validation 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://json-repair.agentdiet.dev/v1/b2a-router)

## Output

Returns a compressed (up to 85% token reduction) list of matching MCP servers or A2A tools relevant to the query, including tool descriptors that have passed the Prompt-Guard firewall. When an endpoint URL is submitted, returns verification status indicating whether it is indexed and flagged for safety.

## 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/json-repair-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-proxy-d07fc30d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from json-repair.agentdiet.dev](https://www.zero.xyz/host/json-repair.agentdiet.dev/llms.txt)