Split a large text file into chunks of ~N words each (default 3000). Saves chunks and a _meta.json index to the output directory. After splitting, use book_chunk to iterate through them.
AI agents use book_split to create or update resources in Self-hosted MCP server for Claude — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Self-hosted MCP server for Claude environment.
This tool reads a source file and writes multiple output files (chunks plus a metadata index) to a directory. It creates new files on the local filesystem, which is a Write operation. It does not execute code, delete data, or involve financial transactions. Severity is medium because it writes potentially many files to arbitrary output directories on the local machine.
From the tool's definition Split a large text file into chunks...Saves chunks and a _meta.json index to the output directory
Attacks that exploit this kind of access
Split a large text file into chunks of ~N words each (default 3000). Saves chunks and a _meta.json index to the output directory. After splitting, use book_chunk to iterate through them. It is categorised as a Write tool in the Self-hosted MCP server for Claude MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Self-hosted MCP server for Claude MCP server in PolicyLayer and add a rule for book_split: 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 Self-hosted MCP server for Claude. Nothing to install.
book_split is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the book_split 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 book_split. 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.
book_split is provided by the Self-hosted MCP server for Claude MCP server (leszczynskikarol/mcp-server). 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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