<tool> <purpose>Finds relevant code in an indexed codebase using natural language or keyword queries</purpose> <when_to_use> <scenario>Find specific functions, classes, or code patterns</scenario> <scenario>Get context before making changes to understand dependencies</scenario> <scenario>Explore ...
AI agents call search_codebase to retrieve information from Mcp Deepcontext without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
search_codebase performs semantic search and code retrieval operations without side effects. It queries an indexed codebase to return matching code symbols and implementations, similar to grep or search functionality. There is no code execution, data modification, deletion, or external effects—only information retrieval. This clearly falls under the Read category with low severity.
From the tool's definition Tool purpose is to 'find relevant code in an indexed codebase using natural language or keyword queries' and use cases include 'find specific functions', 'get context before making changes', 'explore how existing systems work', and 'locate examples'.
Documented attack patterns abuse exactly the kind of access search_codebase gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Mcp Deepcontext, and nothing reaches the server without passing your rules. This is the rule we recommend for search_codebase:
{
"version": "1",
"default": "deny",
"tools": {
"search_codebase": {}
}
}search_codebase is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.
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<tool> <purpose>Finds relevant code in an indexed codebase using natural language or keyword queries</purpose> <when_to_use> <scenario>Find specific functions, classes, or code patterns</scenario> <scenario>Get context before making changes to understand dependencies</scenario> <scenario>Explore how existing systems work</scenario> <scenario>Locate examples of API usage or patterns</scenario> </when_to_use> <parameters> <parameter name=. It is categorised as a Read tool in the Mcp Deepcontext MCP Server, which means it retrieves data without modifying state.
Register the Mcp Deepcontext MCP server in PolicyLayer and add a rule for search_codebase: 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 Deepcontext. Nothing to install.
search_codebase 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 search_codebase 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 search_codebase. 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.
search_codebase is provided by the Mcp Deepcontext MCP server (jmerelnyc/mcp-deepcontext). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Mcp Deepcontext, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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4 Mcp Deepcontext tools catalogued and risk-classified — across an index of 43,000+ MCP servers.