# vet402-check (npm · @vet402/check)

Before your agent pays an x402 API, check if vet402 bought it with its own money and what came back.

- Trust score: 68/100 (medium)
- Change this week: +29
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-10-18

## Components

- npm · `@vet402/check`: 68/100 (this document), [markdown](https://verifymcp.io/servers/kzmttkc-vet402-check/vet402-check.md), [page](https://verifymcp.io/servers/kzmttkc-vet402-check/vet402-check)

## Channel facts

- Registry: `npm`
- Package: `@vet402/check`
- Version: `0.2.0`
- 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 2026-10-18.

- **Supply Chain Security**: 100/100
  - No malware found by supply-chain analysis.
  - No known CVEs affecting this package version or its production dependencies.
  - No install/post-install scripts declared.
  - 0 of 68 dependencies flagged as unhealthy.
- **Provenance & Transparency**: 45/100
  - Source repository is publicly reachable at the declared URL.
  - Provenance check failed: no build-provenance attestation is published.
  - Clear OSI-approved license (MIT).
  - Actively maintained (last published 8 days ago).
  - Disclosure check failed: no security disclosure policy was found in the source repository.
- **Schema Quality & AI Usability**: 59/100
  - AI-judged instruction clarity (good).
  - Context-footprint check failed: tool/resource definitions use about 901 tokens (~300/item across 3 items; 3 tools + 0 resources), over budget; trim descriptions and params.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 3/100
  - Stability observed for 1 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.
- **Tool Safety**: 100/100
  - No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.
  - We read all 3 captured tool definition(s), and no name or description among them implies an irreversible operation.
  - An AI judge read all 4 captured unit(s) of tool text and found none that tries to manipulate the model reading it.
- **Capabilities**: 100/100
  - Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.

## Install

### How do I install the vet402-check MCP server?

vet402-check runs locally as an npm package, launched with npx -y @vet402/check. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.

### Claude

```bash
claude mcp add kzmttkc-vet402-check -- npx -y @vet402/check
```

### Cursor

```json
{
  "mcpServers": {
    "kzmttkc-vet402-check": {
      "command": "npx",
      "args": [
        "-y",
        "@vet402/check"
      ]
    }
  }
}
```

### VS Code

```json
{
  "servers": {
    "kzmttkc-vet402-check": {
      "command": "npx",
      "args": [
        "-y",
        "@vet402/check"
      ]
    }
  }
}
```

### Codex

```bash
codex mcp add kzmttkc-vet402-check -- npx -y @vet402/check
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "kzmttkc-vet402-check": {
      "type": "local",
      "command": [
        "npx",
        "-y",
        "@vet402/check"
      ],
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add kzmttkc-vet402-check --command npx --arg -y --arg @vet402/check
```

### Hermes

```yaml
mcp_servers:
  kzmttkc-vet402-check:
    command: "npx"
    args: ["-y", "@vet402/check"]
```

### Netclaw

```json
{
  "McpServers": {
    "kzmttkc-vet402-check": {
      "Transport": "stdio",
      "Command": "npx",
      "Arguments": [
        "-y",
        "@vet402/check"
      ]
    }
  }
}
```

### Vellum

```bash
assistant mcp add kzmttkc-vet402-check -t stdio -c npx -a -y @vet402/check
```

### Other

```json
{
  "mcpServers": {
    "kzmttkc-vet402-check": {
      "command": "npx",
      "args": [
        "-y",
        "@vet402/check"
      ]
    }
  }
}
```

## 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.

### 2026-10-17 (score 68, +30)

- [security improvement] Injection markers: unverified → pass
- [security improvement] Known CVEs: partial → pass
- [security] First check of Judged manipulation: pass
- [functional regression] Security disclosure: fail → unverified
- [functional improvement] Tool coverage: unverified → 100
- [functional improvement] Stability: unverified → 0.00
- [functional improvement] MCP protocol: unverified → pass
- [functional] First check of Schema quality: fail
- [functional] First check of Destructive annotations: pass
- [functional] First check of Schema quality: fail
- [functional] First check of Schema quality: good
- [functional] First check of Tool coverage: 100
- [functional] Dependency health: partial → 1.00

### 2026-10-16 (score 38, −1)

- [security regression] Known CVEs: pass → partial
- [functional] Dependency health: 1.00 → partial

### 2026-10-14 (score 39, 0)

- [security] Stability: Stability not yet verified: this package could not be installed in a clean environment, so we have no schema to compare.
- [security] Tool safety: Tool safety not yet verified: this package could not be installed in a clean environment, so we have no tool text to scan.
- [functional] Schema quality: Schema quality not yet verified: this package could not be installed in a clean environment, so we have no schema to assess.
- [functional] Capabilities: Protocol version not yet verified: this package could not be installed in a clean environment, so we never saw its MCP handshake.
- [functional] Tool coverage: Tool coverage not yet verified: this package could not be installed in a clean environment, so we have no tool definitions to assess.

### 2026-10-13 (score 39, 0)

- [functional regression] Security disclosure: unverified → fail

### 2026-10-11 (score 39)

First indexed and scored.

## MCP tools (3)

### `check_before_paying` (~411 tokens)

Look an x402 or MPP seller up in vet402's public record

Give the URL you are about to pay (and, if you have them, the chain and the payTo from the 402). Returns what vet402's public record holds about that seller: how many purchases vet402 made with its own money on Solana, Tempo, Base or Algorand, how many settled, how many came back with an answer, the newest purchase with its tx, the failures counted against the seller and the ones that are not, the grade as vet402 prints it (measuring while there are too few purchases), the signed records published for that seller, and whether the payTo matches one vet402 recorded. If vet402 has no record of the seller, it says so. The answer starts with a verdict (pay, avoid or unknown) and one sentence of why, from the same numbers: pay when vet402's paid purchases came back with an answer often enough, avoid when they mostly did not (only failures on the seller's side count), unknown when there is too little to tell. Reads public files only: no key, no payment.

Input parameters:

- `amount` (string): The amount in the 402, in atomic units; compared with what vet402 paid for this URL (reason price_jump)
- `asset` (string): The asset in the 402 (mint or token address); compared with the assets vet402 paid this seller in (reason asset_unseen)
- `chain` (string): solana, tempo, base, algorand, or a CAIP-2 id such as eip155:8453
- `explain` (boolean): Also list the purchases the answer rests on, with date and tx
- `pay_to` (string): The payTo (recipient) in the 402 you hold
- `url` (string, required): The resource URL about to be paid
- `verify_newest_record` (boolean): Also verify the newest signed record of this seller (signature, Merkle proof, payment and anchor on chain)

### `verify_record` (~179 tokens)

Verify one vet402 signed record

Give a record id (obs_YYYY-MM-DD_NNNNNN) or the https URL of a published record. Checks, without taking vet402's word for it: the bytes are the ones the records index lists, the signer is a vet402 observation key, the EIP-712 signature, that the verdict follows from the recorded checks, the Merkle proof to the day's root, the payment on chain over public RPC, and the day's root in a Solana memo sent by vet402's anchor wallet. Result: OK, OK_NOT_ANCHORED, OK_OFFLINE or FAIL, with one line per check.

Input parameters:

- `offline` (boolean): Skip the reads from chain (payment and anchor)
- `record` (string, required): Record id (obs_2026-09-28_000164) or https URL of a record JSON

### `diagnose_failed_payment` (~256 tokens)

Diagnose an x402 payment that brought no answer

Give the transaction of a payment you made (a Solana signature or a Base tx hash), the URL you paid and, if you have it, the HTTP status the seller answered. Reads the payment from public RPC (settled or not, payTo, amount, asset, time) and puts it next to vet402's own purchases from the same seller on the same chain within 24 hours. Returns fault: seller_side, facilitator_side, buyer_side or undetermined, with reasons. seller_side needs a settled payment to a payTo vet402 paid this seller, a status vet402's rules put on the seller, and vet402's own paid purchases in the window failing too with none delivered; anything less is undetermined. For seller_side it adds an evidence pack (JSON and Markdown) to hand to the seller; nothing is sent. Reads public data only: no key, no payment.

Input parameters:

- `chain` (string): solana or base (default: from the shape of tx)
- `status` (integer): The HTTP status the seller answered after the payment
- `tx` (string, required): Solana transaction signature or Base tx hash of the payment
- `url` (string, required): The URL that was paid

## Diagnostics

Captured diagnostic sections: Provenance, Dependencies. The full working is on the page: https://verifymcp.io/servers/kzmttkc-vet402-check/vet402-check#diagnostics

## Score history

- 2026-10-18: 68
- 2026-10-17: 68
- 2026-10-16: 38
- 2026-10-15: 39
- 2026-10-14: 39
- 2026-10-13: 39
- 2026-10-12: 39
- 2026-10-11: 39

## Common questions

### What is the vet402-check MCP server?

vet402-check is an MCP server listed in the public MCP registry as io.github.kzmttkc/vet402-check. Before your agent pays an x402 API, check if vet402 bought it with its own money and what came back. This page covers its npm package (@vet402/check).

### Is the vet402-check MCP server safe to use?

vet402-check scores 68 out of 100 on VerifyMCP. We found no known CVEs affecting it as of 18 October 2026. It declares no install or post-install scripts. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.

### What tools does the vet402-check MCP server expose?

vet402-check exposes 3 tools: check_before_paying, verify_record, diagnose_failed_payment. Their descriptions and schemas cost roughly 846 tokens of context every time the server is loaded.

### Is the vet402-check MCP server still maintained?

vet402-check is still listed as active in the MCP registry. We last reached this channel on 18 October 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.

### What licence is the vet402-check MCP server under?

vet402-check declares the MIT licence, which is OSI-approved. That covers the source only, and says nothing about the cost of any service it calls.

## Links

- npm package: https://www.npmjs.com/package/@vet402/check
- Socket report: https://socket.dev/npm/package/@vet402/check
- Repository: https://github.com/kzmttkc/vet402-delivery
- Website: https://kzmttkc.github.io/vet402-delivery/use.html
- Changelog RSS feed: https://verifymcp.io/servers/kzmttkc-vet402-check/vet402-check.xml
- Changelog JSON feed: https://verifymcp.io/servers/kzmttkc-vet402-check/vet402-check.json
- HTML version of this page: https://verifymcp.io/servers/kzmttkc-vet402-check/vet402-check