# B20 Check (remote · b20check.com)

Verify B20 tokens on Base: issuer powers, imposter detection, signed EIP-712 verdicts.

- Trust score: 69/100 (medium)
- Change this week: +4
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-08-03

## Components

- remote · `b20check.com`: 69/100 (this document), [markdown](https://verifymcp.io/servers/com-b20check-b20check/b20check.md), [page](https://verifymcp.io/servers/com-b20check-b20check/b20check)
- npm · `b20check-mcp`: 62/100, [markdown](https://verifymcp.io/servers/com-b20check-b20check/b20check-mcp.md), [page](https://verifymcp.io/servers/com-b20check-b20check/b20check-mcp)

## Channel facts

- Endpoint: `https://b20check.com/mcp`
- Transports: `streamable-http`
- Auth: `none`
- Version: `0.1.1`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. Scores are 0–100 per category. Scoring method: https://verifymcp.io/docs/scoring (what has changed: https://verifymcp.io/docs/scoring/changelog)

Scored 2026-08-03.

- **Endpoint Security**: 63/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - Authorisation not fully verified: no authorisation is required to call this server, and 2 tool(s) never declared a destructiveHint. The MCP spec treats an absent hint as destructive by default, so we cannot call this surface safe.
  - HTTPS is enforced; there's no plaintext access path.
  - The HSTS (Strict-Transport-Security) header is present.
  - DNSSEC check failed: this domain isn't protected by DNSSEC.
- **Transport & Reachability**: 100/100
  - Verified streamable-http transport via a live MCP handshake.
- **Schema Quality & AI Usability**: 73/100
  - AI-judged instruction clarity (excellent).
  - Context-footprint check failed: tool/resource definitions use about 350 tokens (~175/item across 2 items; 2 tools + 0 resources), over budget; trim descriptions and params.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 27/100
  - Stability observed for 8 of 30 days with no destabilising changes; credit accrues until the full window elapses.
- **Tool Coverage**: 100/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 100% of tool parameters carry a description.
  - Structured output schemas are declared (100% of tools); any adoption earns full credit.
- **Capabilities**: 100/100
  - Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.

## Install

### Claude

```bash
claude mcp add --transport http com-b20check-b20check https://b20check.com/mcp
```

### Codex

```toml
[mcp_servers.com-b20check-b20check]
url = "https://b20check.com/mcp"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "com-b20check-b20check": {
      "type": "remote",
      "url": "https://b20check.com/mcp",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add com-b20check-b20check --url https://b20check.com/mcp --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  com-b20check-b20check:
    url: "https://b20check.com/mcp"
```

### Other

```json
{
  "mcpServers": {
    "com-b20check-b20check": {
      "type": "http",
      "url": "https://b20check.com/mcp"
    }
  }
}
```

The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.

## Changelog

Every change recorded for this component, newest first. Days that predate change tracking, or that we cannot explain, say so: "we were watching and nothing happened" and "we were not watching" are different claims.

### 2026-08-03 (score 69, +1)

No change was recorded against any check on this day. Stability & Change Management went from 23 to 27. That category is still filling its 30-day observation window: 7 days of observed history at the previous scan, 8 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-08-01 (score 68, +1)

No change was recorded against any check on this day. Stability & Change Management went from 17 to 20. That category is still filling its 30-day observation window: 5 days of observed history at the previous scan, 6 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-07-31 (score 67, 0)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-07-30 (score 67, +1)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-07-29 (score 66, +1)

No change was recorded against any check on this day. Stability & Change Management went from 7 to 10. That category is still filling its 30-day observation window: 2 days of observed history at the previous scan, 3 at this one. The score rises as the window fills, whether or not the server changes.

### 2026-07-27 (score 65, +1)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-07-26 (score 64)

First indexed and scored.

## MCP tools (2)

### `verify_b20_token` (~245 tokens)

Verify a B20 token

Check whether a token address on Base is a legitimate B20 token and what powers its issuer holds. Call this BEFORE helping the user buy, swap, approve, or move value into any B20 token you have not already verified in this conversation (B20 addresses usually start with 0xb20). Returns a signed verdict: isB20, a verdict of ok/caution/danger/not_applicable, risk flags (mint, freeze, seize, pause, admin, impostor, and more), and the data freshness (indexed/live/not_indexed). not_applicable means the address is not a B20 and not a recognized canonical asset: do NOT read it as safe, there is simply nothing B20-specific to vouch for. Never treat a not_indexed or error result as safe either: a token that cannot be fully checked is never a clean pass. The result carries an EIP-712 signature the user can verify independently; do not overstate it as a guarantee of safety, report what the flags and verdict actually say.

Input parameters:

- `address` (string, required): The token contract address on Base to check (B20 addresses usually start with 0xb20).

Output parameters:

- `address` (string): The checked token address (EIP-55).
- `attestation`: Block-pinned EIP-712 attestation; verification recipe at https://b20check.com/v1/schema
- `creation`
- `dataSource` (string): Data freshness. not_indexed = powers could not be fully checked; never a clean pass.
- `flags` (array): Risk flags. Derivation rules: https://b20check.com/methodology
- `isB20` (boolean): True only for a factory-native B20 token.
- `issuerActivity`
- `issuerPowers`: mint/burn/pause/freeze/seize/admin powers, latent-inclusive.
- `network` (string)
- `variant`
- `verdict` (string): Roll-up verdict. not_applicable = out of scope, do NOT read as safe.

### `b20_stats` (~51 tokens)

B20 Check usage

Report B20 Check's own live usage: how many B20 tokens are indexed and how many paid calls and unique payers it has served in the last 30 days (from the public Coinbase discovery API).

Output parameters:

- `l30DaysTotalCalls` (number|null)
- `l30DaysUniquePayers` (number|null)
- `lastUpdated` (string)
- `snapshotBlock` (number)
- `source` (string)
- `tokensIndexed` (number)

## Diagnostics

Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/com-b20check-b20check/b20check#diagnostics

## Score history

- 2026-08-03: 69
- 2026-08-02: 68
- 2026-08-01: 68
- 2026-07-31: 67
- 2026-07-30: 67
- 2026-07-29: 66
- 2026-07-28: 65
- 2026-07-27: 65
- 2026-07-26: 64

## Links

- Remote endpoint: https://b20check.com/mcp
- Website: https://b20check.com/
- Changelog RSS feed: https://verifymcp.io/servers/com-b20check-b20check/b20check/changelog.xml
- Changelog JSON feed: https://verifymcp.io/servers/com-b20check-b20check/b20check/changelog.json
- HTML version of this page: https://verifymcp.io/servers/com-b20check-b20check/b20check