AI agents call list_books_by_author to retrieve information from Lyceum without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and displays existing book data filtered by author. It performs a read-only query against the Calibre library without creating, modifying, deleting, or executing any operations. The blast radius of misuse is minimal—an agent could only retrieve information about books, which poses no security or operational risk.
From the tool's definition Tool name 'list_books_by_author' and description 'List all books by a specific author' indicate a query/retrieval operation with no modification or deletion of data.
Attacks that exploit this kind of access
List all books by a specific author. It is categorised as a Read tool in the Lyceum MCP Server, which means it retrieves data without modifying state.
Register the Lyceum MCP server in PolicyLayer and add a rule for list_books_by_author: 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 Lyceum. Nothing to install.
list_books_by_author 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 list_books_by_author 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 list_books_by_author. 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.
list_books_by_author is provided by the Lyceum MCP server (matthewp/lyceum). 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.
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