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

Searches a meta-index of 500+ MCP servers and A2A tools by capability query, returning matching endpoints with token-compressed results and Prompt-Guard firewall protection.

## Facts

- Endpoint: GET https://onchain-risk.agentdiet.dev/v1/web-rag-shield-dag?utm_source=zero.xyz
- Price: $0.01/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-21
- Activations on Zero: 0
- Provider: onchain-risk.agentdiet.dev
- Website: https://onchain-risk.agentdiet.dev
- Canonical page: https://www.zero.xyz/c/onchain-risk-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-52707ca9
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_nCieaxKYQ7HKXPFnEMxcy

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 onchain-risk-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-52707ca9
```

Example prompt: Search for available MCP servers or A2A tools that handle 'context compression' — I want to find the best matching endpoints I can connect to for that capability.

## When to prefer this

Choose this endpoint when an AI agent needs to dynamically discover which MCP servers or A2A tools support a given capability, rather than hardcoding a specific tool. Ideal for swarm orchestrators, meta-agents, or tool registries that need to route tasks to the best available sub-agent. Prefer this over manual tool registries when you need broad coverage across 500+ indexed servers with built-in safety filtering.

## Known failure modes

- Empty query string returns validation error
- Query matches zero indexed tools — returns empty result set
- Queried URL is unreachable or not an MCP/A2A endpoint — returns non-compliant status
- Rate limiting or payment failure (x402) blocks the request
- Firewall flags query as potentially adversarial and blocks response

## 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://onchain-risk.agentdiet.dev/v1/web-rag-shield-dag)

## Output

Returns a token-compressed list of matching MCP servers and A2A tool endpoints relevant to the query, including capability descriptions, endpoint URLs, and compliance/metadata signals. Results pass through a Prompt-Guard firewall to screen for malicious content.

## 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/onchain-risk-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-52707ca9/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from onchain-risk.agentdiet.dev](https://www.zero.xyz/host/onchain-risk.agentdiet.dev/llms.txt)