Search highlights by text query
AI agents call readwise_search_highlights to retrieve information from Readwise MCP Server without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
This tool queries and retrieves highlights matching a text search. It has no side effects, does not modify, delete, or execute code. The search operation is a classic Read category action. Severity is low because misuse would only expose existing user data (highlights already in their Readwise account) with no destructive, financial, or execution risks.
From the tool's definition Tool name contains 'search' and description states 'Search highlights by text query' — a read-only retrieval operation with no data modification.
Attacks that exploit this kind of access
Search highlights by text query. It is categorised as a Read tool in the Readwise MCP Server MCP Server, which means it retrieves data without modifying state.
Register the Readwise MCP Server MCP server in PolicyLayer and add a rule for readwise_search_highlights: 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 Readwise MCP Server. Nothing to install.
readwise_search_highlights 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 readwise_search_highlights 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 readwise_search_highlights. 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.
readwise_search_highlights is provided by the Readwise MCP Server MCP server (ngpestelos/readwise-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.
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