grep · MCP Claude Code MCP: Risk & Policy

WHAT IT DOES

What grep does on MCP Claude Code

AI agents call grep to retrieve information from MCP Claude Code without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

WHY IT NEEDS A POLICY

Why grep needs a policy

The tool name 'grep' strongly suggests a search/pattern-matching operation over files, which is a Read operation. However, the empty description lowers confidence. In the context of sibling tools like 'read', 'directory_tree', and 'grep_ast', this is almost certainly a file content search tool. Severity is medium because searching could expose sensitive file contents across a codebase.

From the tool's definition Tool name 'grep' and server context involving codebase analysis and file system interactions. Description is empty.

Attacks that exploit this kind of access

Questions about grep

What does the grep tool do? +

grep. It is categorised as a Read tool in the MCP Claude Code MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on grep? +

Register the MCP Claude Code MCP server in PolicyLayer and add a rule for grep: 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 MCP Claude Code. Nothing to install.

What risk level is grep? +

grep is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit grep? +

Yes. Add a rate_limit block to the grep 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.

How do I block grep completely? +

Set action: deny in the PolicyLayer policy for grep. 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.

What MCP server provides grep? +

grep is provided by the MCP Claude Code MCP server (sdglbl/mcp-claude-code). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.