# B20 Check (npm · b20check-mcp)

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

- Trust score: 62/100 (medium)
- Change this week: +23
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-08-03

## Components

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

## Channel facts

- Registry: `npm`
- Package: `b20check-mcp`
- Version: `0.1.1`
- Transport: `stdio`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically from public evidence about the published package, including repeated runs of it in an isolated sandbox, 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.

- **Supply Chain Security**: 87/100
  - No malware found by supply-chain analysis.
  - Only part of the dependency tree could be resolved (113 of 117), so this covers what we could see, not the whole tree.
  - No install/post-install scripts declared.
  - Only part of the dependency tree could be resolved (113 of 117), so this covers what we could see, not the whole tree.
- **Provenance & Transparency**: 19/100
  - Repository check failed: no source repository is declared.
  - Provenance check failed: no build-provenance attestation is published.
  - Clear OSI-approved license (MIT).
  - Actively maintained (last published 21 days ago).
  - Security-disclosure policy not yet verified: we couldn't inspect the source repository.
- **Schema Quality & AI Usability**: 67/100
  - AI-judged instruction clarity (good).
  - 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.
- **Capabilities**: 100/100
  - Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.

## Install

### Claude

```bash
claude mcp add com-b20check-b20check -- npx -y b20check-mcp
```

### Codex

```bash
codex mcp add com-b20check-b20check -- npx -y b20check-mcp
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "com-b20check-b20check": {
      "type": "local",
      "command": [
        "npx",
        "-y",
        "b20check-mcp"
      ],
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add com-b20check-b20check --command npx --arg -y --arg b20check-mcp
```

### Hermes

```yaml
mcp_servers:
  com-b20check-b20check:
    command: "npx"
    args: ["-y", "b20check-mcp"]
```

### Other

```json
{
  "mcpServers": {
    "com-b20check-b20check": {
      "command": "npx",
      "args": [
        "-y",
        "b20check-mcp"
      ]
    }
  }
}
```

## 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.

### 2026-08-02 (score 62, +47)

- [security regression] Provenance: unverified → fail
- [security improvement] Install scripts: unverified → pass
- [security improvement] Known CVEs: unverified → partial
- [security improvement] Malware scan: unverified → pass
- [functional improvement] Schema quality: unverified → good
- [functional improvement] MCP protocol: unverified → pass
- [functional improvement] Stability: unverified → 0.23
- [functional improvement] License: unverified → pass
- [functional improvement] Dependency health: unverified → partial
- [functional improvement] Maintenance: unverified → pass
- [functional] Licence: MIT

### 2026-08-01 (score 15, −6)

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

### 2026-07-31 (score 21, −18)

- [security regression] Malware scan: pass → unverified

### 2026-07-27 (score 39)

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).

### `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).

## Diagnostics

Captured diagnostic sections: Provenance, Dependencies. The full working is on the page: https://verifymcp.io/servers/com-b20check-b20check/b20check-mcp#diagnostics

## Score history

- 2026-08-03: 62
- 2026-08-02: 62
- 2026-08-01: 15
- 2026-07-31: 21
- 2026-07-30: 39
- 2026-07-28: 39
- 2026-07-27: 39

## Links

- npm package: https://www.npmjs.com/package/b20check-mcp
- Socket report: https://socket.dev/npm/package/b20check-mcp
- Website: https://b20check.com/
- Changelog RSS feed: https://verifymcp.io/servers/com-b20check-b20check/b20check-mcp/changelog.xml
- Changelog JSON feed: https://verifymcp.io/servers/com-b20check-b20check/b20check-mcp/changelog.json
- HTML version of this page: https://verifymcp.io/servers/com-b20check-b20check/b20check-mcp