isbn_check_digit
ISBN Check Digit Validator — Validate a 10- or 13-digit ISBN's check digit (ISO 2108), or compute the check digit a 9- or 12-digit ISBN prefix would need.
This record as markdown: /tools/com-wingmanprotocol-agent-gateway/isbn-check-digit.md
What isbn_check_digit does on Gateway
AI agents call isbn_check_digit 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.
| Parameter | Type | Required | Description |
|---|---|---|---|
isbn | string | Yes | ISBN (hyphens/spaces allowed) |
mode | string | — | validate | check_digit (default validate) |
Parameters from the server's own tool schema.
Why isbn_check_digit is rated Low
This is a pure computational utility that reads ISBN numeric input and returns validation results or computed check digits. It has no side effects, does not alter any state, and poses minimal security risk if misused by an AI agent—worst case, an agent receives incorrect validation output, which does not compromise system integrity or data.
From the tool's definition Tool performs validation and computation of ISBN check digits per ISO 2108 standard. No data is created, modified, deleted, or irreversibly changed. No code execution or financial operations occur.
Attacks that exploit this kind of access
The rule that runs isbn_check_digit safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Gateway, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For isbn_check_digit, this is the rule to start with:
isbn_check_digit is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Gateway, apply this rule, and every isbn_check_digit call is checked against it from then on.
Questions about isbn_check_digit
ISBN Check Digit Validator — Validate a 10- or 13-digit ISBN's check digit (ISO 2108), or compute the check digit a 9- or 12-digit ISBN prefix would need. It is categorised as a Read tool in the Gateway MCP Server, which means it retrieves data without modifying state.
isbn_check_digit accepts 2 parameters: isbn, mode. Required: isbn. The full parameter table on this page comes from the server's own tool schema.
Register the Gateway MCP server in PolicyLayer and add a rule for isbn_check_digit: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Gateway. Nothing to install.
isbn_check_digit is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the isbn_check_digit rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for isbn_check_digit. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
isbn_check_digit is provided by the Gateway MCP server (https://wingmanprotocol.com/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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