AI agents call list_books_by_series 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 presents information about books organized by series. It performs a read-only query operation with no side effects, no code execution, and no data modification. The blast radius if misused is minimal—at worst, an agent could retrieve library metadata it shouldn't see, which is a confidentiality concern but not operationally destructive. This clearly falls under the 'Read' category.
From the tool's definition Tool name 'list_books_by_series' and description 'List all books in a series' indicate data retrieval with no modification or execution. The action is querying/listing existing data from the Calibre library.
Attacks that exploit this kind of access
List all books in a series, ordered by series index. The series_id can be found in the series_id field of any book detail or book summary. 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_series: 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_series 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_series 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_series. 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_series 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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