# checksum

Checksum Validator — Validate or compute check digits for IBAN, ISBN-10, and ISBN-13 identifiers.

Agent View of the PolicyLayer registry record for `checksum`. HTML page: https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/checksum

## Facts

- Tool: `checksum`
- Server: Gateway (`https://wingmanprotocol.com/mcp`) — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway.md
- Homepage: https://github.com/WingmanProtocol-Agent-Gateway/wingman-agent-gateway
- Risk category: Read (Low risk)
- Registry record: grade F, identity unverified
- Server auth posture: open
- Server rate-limited: no
- Parameters: 3 (1 required)
- Recommended policy verdict: Allowed

## Parameters

| Parameter | Type | Required | Description |
| --- | --- | --- | --- |
| `mode` | string | no | validate or check_digit |
| `value` | string | yes | Value to check (spaces/dashes ignored) |
| `scheme` | string | no | Checksum scheme |

Parameters from the server's own tool schema.

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "checksum",
    "arguments": {
      "value": "<value>"
    }
  }
}
```

## Why checksum is rated Low

Checksum computation and validation are pure computational functions that retrieve or derive data without modifying, deleting, or executing arbitrary operations. Even though IBAN involves financial identifiers, the tool only validates/computes checksums rather than moving money or making financial commitments. No irreversible changes, no code execution, no financial transactions.

From the tool's own definition: "Tool description states it 'Validate or compute check digits' for financial and bibliographic identifiers (IBAN, ISBN)."

## Use case

AI agents call checksum to retrieve information from Gateway without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

## Recommended policy (PolicyLayer)

Verdict: **Allowed**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Gateway:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "checksum": {}
  }
}
```

## Other tools on Gateway (270)

- `cancel_watch` — Destructive — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/cancel-watch.md
- `forget_memories` — Destructive — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/forget-memories.md
- `text_truncate_ellipsis` — Destructive — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/text-truncate-ellipsis.md
- `vault_delete` — Destructive — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/vault-delete.md
- `arena_call` — Execute — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/arena-call.md
- `bitwise` — Execute — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/bitwise.md
- `browse` — Execute — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/browse.md
- `browse_back` — Execute — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/browse-back.md
- `browse_click` — Execute — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/browse-click.md
- `browse_close` — Execute — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/browse-close.md
- `browse_evaluate` — Execute — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/browse-evaluate.md
- `browse_fill` — Execute — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/browse-fill.md
- `browse_navigate` — Execute — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/browse-navigate.md
- `browse_open` — Execute — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/browse-open.md
- `browse_select` — Execute — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/browse-select.md
- `browse_solve_challenge` — Execute — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/browse-solve-challenge.md
- `browse_type` — Execute — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/browse-type.md
- `browse_wait_for` — Execute — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/browse-wait-for.md
- `coach_mission` — Execute — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/coach-mission.md
- `dice_notation_roll` — Execute — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/dice-notation-roll.md
- `gen_avatar_video` — Execute — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/gen-avatar-video.md
- `gen_id_portrait` — Execute — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/gen-id-portrait.md
- `gen_image` — Execute — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/gen-image.md
- `gen_video` — Execute — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/gen-video.md
- `hmac` — Execute — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/hmac.md
- `markdown_to_html` — Execute — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/markdown-to-html.md
- `matrix` — Execute — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/matrix.md
- `regex_tester` — Execute — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/regex-tester.md
- `request_handoff` — Execute — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/request-handoff.md
- `retry_backoff` — Execute — https://policylayer.com/tools/com-wingmanprotocol-agent-gateway/retry-backoff.md
- …and 240 more: https://policylayer.com/tools/com-wingmanprotocol-agent-gateway.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=com-wingmanprotocol-agent-gateway · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/com-wingmanprotocol-agent-gateway