AI agents call list_series to retrieve information from Calibre 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 information about books in a series without creating, modifying, deleting, or executing any operations. It is a pure read operation with no side effects on the Calibre library.
From the tool's definition Tool name 'list_series' and description 'List all books in a series' indicate querying/retrieval of existing data with no modification or deletion. The phrase 'sorted by series_index' confirms it returns structured data.
Attacks that exploit this kind of access
List all books in a series, sorted by series_index. It is categorised as a Read tool in the Calibre MCP Server, which means it retrieves data without modifying state.
Register the Calibre MCP server in PolicyLayer and add a rule for list_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 Calibre. Nothing to install.
list_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_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_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_series is provided by the Calibre MCP server (xmkevinchen/calibre-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 →