# Council of AI — MCP Registry Population Slice

> Council of AI — MCP Registry Population Slice is a paid API for AI agents from councilof.ai, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-02).

Returns a signed, verifiable population slice of server names indexed from the official MCP registry, with attestation metadata and cryptographic provenance.

## Facts

- Endpoint: GET https://councilof.ai/api/pop/mcp-registry?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-02
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/council-of-ai-mcp-registry-population-slice-5aacd0eb
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_rPvfJ3w5HC2vRx13TeGM3

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 council-of-ai-mcp-registry-population-slice-5aacd0eb
```

Example prompt: Pull the latest signed population slice from the Council of AI MCP registry endpoint — I want to see how many server names are currently indexed, along with the attestation hash and timestamp so I can verify the data.

## When to prefer this

Choose this endpoint when you need a cryptographically signed, independently verified snapshot of MCP registry server names with full attestation metadata — not just a raw registry dump. It is ideal when auditability, tamper-evidence, and reproducibility matter, such as compliance checks, ecosystem audits, or any workflow that needs to verify the provenance of MCP server population data.

## Known failure modes

- Payment not fulfilled — 402 response if x402 payment is not provided or insufficient
- Invalid method — only GET/HEAD/DELETE accepted; POST or PUT will be rejected
- Attestation signature may be null if the slice is an unsigned supporting run rather than an issued measurement card
- Stale data — as_of timestamp may lag real-time registry updates
- Registry source unavailable — upstream MCP registry fetch failure could result in stale or empty rows

## How this service works

We measure how AI systems behave against frozen, published tests and publish checkable evidence. Issued measurement cards are signed; unsigned supporting runs are labelled. Read the live board and corrections ledger.

## Output

Returns a JSON object with the total count of MCP registry server names (n), a unique slice ID, raw population rows, an as_of timestamp, indexing state, schema version, settlement details (payer, network, transaction), source file references, and a signed attestation block containing a card schema URL, SHA-256 of the payload, surface label, and an optional ed25519 signature for cryptographic verification.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "n": 354,
  "id": "mcp-registry",
  "kind": "slice",
  "rows": "<the population rows / artifact bytes, verbatim>",
  "as_of": "2026-09-22T08:27:50Z",
  "state": "INDEXED",
  "n_unit": "own server names in the official MCP registry (one row per name, classified on isLatest=true)",
  "schema": "csoai.population-door/0.1",
  "settle": {
   "payer": "<0x… or null>",
   "network": "<caip2 or null>",
   "transaction": "<0x… or null>"
  },
  "source": [
   "/interop/mcp-registry-self-listings-2026-09-22.json",
   "/interop/agent-population-2026-09-17.json"
  ],
  "attestation": {
   "schema": "https://councilof.ai/schema/card-v0.json",
   "sha256": "<hex>",
   "payload": {
    "kind": "csoai.population.slice/0.1",
    "rows_sha256": "<hex>"
   },
   "surface": "population.slice",
   "sig_ed25519": "<hex or null>"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/council-of-ai-mcp-registry-population-slice-5aacd0eb/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from councilof.ai](https://www.zero.xyz/host/councilof.ai/llms.txt)