# B20 Token Safety Check

> B20 Token Safety Check is a paid API for AI agents from 402.com.tr, paid per call via x402, $0.04/call, status unknown (last checked 2026-09-15).

Checks a Base B20 token address for protocol-level powers (freeze, seize, pause, rebase, uncapped-mint) and returns a hold/caution/avoid safety verdict

## Facts

- Endpoint: GET https://402.com.tr/api/x402/b20-safety
- Price: $0.04/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/b20-token-safety-check-f5e712cd
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_TpsaWQ4FRPpW5SUJgPSCt

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-token-safety-check-f5e712cd
```

Example prompt: Can you run a B20 safety check on the token at address 0xAbCd...1234 on Base? I want to know if the issuer can freeze holders or seize balances before I buy any.

## When to prefer this

Use this endpoint when evaluating B20 tokens on Base specifically, where standard ERC-20 safety tools miss protocol-level issuer powers like balance seizure (burnBlocked) and holder freezing via Policy Registry. Prefer this over generic token audits when the token is a Base native precompile standard token and you need to quickly assess custodial risk before investing.

## Known failure modes

- Invalid or non-B20 token address returns an error or empty result
- Address is an ERC-20 rather than B20 precompile token — results may be inapplicable
- Network timeouts when querying Base chain state
- Address parameter missing — API returns 400 or validation error
- Token contract not yet deployed or recently removed from chain

## How this service works

🆕 Live — B20 is Base's native precompile token standard, and unlike ERC-20 a B20 issuer can freeze holders (Policy Registry) and even SEIZE your balance (burnBlocked) at the protocol level. This reads exactly those powers — seizable, freezable, paused, rebase, uncapped-mint — into one hold/caution/avoid verdict, and says whether they are the compliance surface a tokenized stock must carry or a token merely wearing an equity ticker. The first B20-aware safety check on Base.

## Output

A safety verdict (hold/caution/avoid) for the queried B20 token, with individual flags indicating whether the token is seizable, freezable, paused, rebasing, or has uncapped minting — summarizing the protocol-level powers the issuer holds over token holders.

## 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": [
      "address"
     ],
     "properties": {
      "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-token-safety-check-f5e712cd/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)