AI agents call get_book to retrieve information from Hardcover without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and queries book data without modifying, deleting, or executing any operations. It is a straightforward read operation that returns information about a book resource. No reversible or irreversible changes are made to data, making it the lowest-risk category.
From the tool's definition Tool name 'get_book' and description 'Get detailed info about a specific book' indicate a retrieval operation with no side effects. The verb 'Get' combined with 'detailed info' clearly describes a query operation.
Attacks that exploit this kind of access
Get detailed info about a specific book by its Hardcover ID or slug. It is categorised as a Read tool in the Hardcover MCP Server, which means it retrieves data without modifying state.
Register the Hardcover MCP server in PolicyLayer and add a rule for get_book: 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 Hardcover. Nothing to install.
get_book 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 get_book 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 get_book. 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.
get_book is provided by the Hardcover MCP server (kristianedlund/hardcover-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
Teams ship this data inside their own products. See what a licence covers →