Fetch text from a library source. Full-text sources return cleaned text (truncated at 200k chars). Metadata sources return item details and an external URL. Returns: { title, authors, year?, language?, text?, charCount?, truncated?, metadataOnly?, externalUrl?, note? }
AI agents call library_read to retrieve information from Alexandria MCP without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool retrieves and returns existing data from digital libraries (text, metadata, external URLs) without creating, modifying, deleting, or executing anything. The output structure confirms it is purely informational—no state changes occur on the library or broader system. It fits the Read category: retrieves or queries data with no side effects.
From the tool's definition Tool name 'library_read' and description 'Fetch text from a library source' and 'return cleaned text' and 'return item details' indicate data retrieval with no modification or side effects.
Attacks that exploit this kind of access
Fetch text from a library source. Full-text sources return cleaned text (truncated at 200k chars). Metadata sources return item details and an external URL. Returns: { title, authors, year?, language?, text?, charCount?, truncated?, metadataOnly?, externalUrl?, note? }. It is categorised as a Read tool in the Alexandria MCP MCP Server, which means it retrieves data without modifying state.
Register the Alexandria MCP server in PolicyLayer and add a rule for library_read: 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 Alexandria MCP. Nothing to install.
library_read 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 library_read 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 library_read. 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.
library_read is provided by the Alexandria MCP server (the-40-thieves/alexandria-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.
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