# B20 Policy Members Enumerator

> B20 Policy Members Enumerator is a paid API for AI agents from 402.com.tr, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-14).

Enumerates the complete membership of a B20 token's blocklist and allowlist by replaying on-chain policy registry events, returning every address ever blocked or whitelisted, when, by whom, and the current member set per scope.

## Facts

- Endpoint: GET https://402.com.tr/api/x402/b20-policy-members
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/b20-policy-members-enumerator-b8b8baef
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_tb2z52n5p9FYxeFCC3kMo

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 b20-policy-members-enumerator-b8b8baef
```

Example prompt: Can you give me the full blocklist and allowlist membership history for this B20 token — every address ever blocked or whitelisted, who did it, and when — using the token address 0xAbC123...?

## When to prefer this

Use this endpoint when you need compliance-grade, full-history enumeration of all addresses ever added to or removed from a B20 token's blocklist or allowlist — not just the current state of a single wallet. Prefer this over the b20-freeze-check endpoint (which answers for one wallet) when you need the entire member set, audit trail, or historical actor/timestamp data for regulatory review, risk analysis, or monitoring. Also use when you have a policy registry ID rather than a token address.

## Known failure modes

- Missing both address and policy parameters — returns 400 bad request requiring at least one
- Invalid or non-B20 token address — no policy registry found, returns empty result or 404
- Non-existent policy ID — returns empty member set
- RPC node timeout when replaying large event histories — returns 503 or partial result
- Malformed address string — returns 400 validation error
- Token with no blocklist/allowlist events — returns empty arrays

## How this service works

🆕 b20-freeze-check answers one wallet; this enumerates the WHOLE list. Replays the Policy Registry's BlocklistUpdated/AllowlistUpdated events into the full membership of a B20's blocklist/allowlist: every address ever blocked or whitelisted, when, by whom, and the current member set per scope. Compliance-grade visibility no other tool provides. Pass address= (token) or policy= (registry policy ID).

## Output

Returns the complete enumerated membership of all blocklist and allowlist scopes for the specified B20 token or policy registry: every address that was ever added or removed, the timestamp and actor for each event, and the current live member set per scope — derived by replaying all BlocklistUpdated and AllowlistUpdated on-chain events.

## 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"
     ],
     "type": "string"
    },
    "pathParams": {
     "type": "object"
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {
      "policy": {
       "type": "string",
       "description": "Registry policy ID (optional)"
      },
      "address": {
       "type": "string",
       "description": "B20 token address"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/b20-policy-members-enumerator-b8b8baef/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from 402.com.tr](https://www.zero.xyz/host/402.com.tr/llms.txt)