Get detailed metadata for a specific book by ID
AI agents call crow_calibre_get_book to retrieve information from Crow without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries and returns book metadata without creating, modifying, deleting, executing code, or performing financial operations. It is a straightforward read operation with minimal security risk. The severity is low because retrieving book metadata has a limited blast radius and no capability to alter system state.
From the tool's definition Tool name 'crow_calibre_get_book' and description 'Get detailed metadata for a specific book by ID' indicate a read-only retrieval operation. The verb 'Get' and the phrase 'detailed metadata' confirm data retrieval with no modification or side effects.
Documented attack patterns abuse exactly the kind of access crow_calibre_get_book gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Crow, and nothing reaches the server without passing your rules. This is the rule we recommend for crow_calibre_get_book:
{
"version": "1",
"default": "deny",
"tools": {
"crow_calibre_get_book": {}
}
} crow_calibre_get_book is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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Get detailed metadata for a specific book by ID. It is categorised as a Read tool in the Crow MCP Server, which means it retrieves data without modifying state.
Register the Crow MCP server in PolicyLayer and add a rule for crow_calibre_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 Crow. Nothing to install.
crow_calibre_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 crow_calibre_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 crow_calibre_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.
crow_calibre_get_book is provided by the Crow MCP server (kh0pper/crow). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Crow, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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