search_codebase

THE RISK

Low Risk

Why search_codebase needs a policy

This tool retrieves and searches existing code data without creating, modifying, deleting, or executing anything. It is a read-only operation that queries a vector-indexed codebase and returns results. No side effects or state changes occur.

From the tool's definition Tool description states it 'Search your codebase' and 'Returns relevant code snippets' — purely retrieval operations with no modification, deletion, or execution. Natural language search is a query mechanism.

Documented attack patterns abuse exactly the kind of access search_codebase gives an agent:

POLICY

How to control search_codebase

PolicyLayer is an MCP gateway — it sits between your AI agents and MCP Codebase Index, and nothing reaches the server without passing your rules. This is the rule we recommend for search_codebase:

policy.json

{
  "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.

Create a free account and register MCP Codebase Index — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

CAP THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More MCP Codebase Index tools

Write repair_index Repair detected index issues by re-indexing missing files and removing orphaned vectors. Write export_visualization_html Export the vector visualization as a standalone HTML file with modern UI. Automatically sa Read check_index Verify index health and detect issues like missing files, orphaned vectors, and dimension Read enhance_prompt Enhance a search query by adding codebase context and technical details. Use this before s Read enhancement_telemetry Get telemetry data for prompt enhancement (success rate, cache hits, latency) Read indexing_status Check the current indexing status and progress. Read visualize_collection Visualize the entire vector database in 2D or 3D space using UMAP dimensionality reduction Read visualize_query Visualize a search query and its retrieved documents in the vector space. USE CASES: - Sh

All 9 MCP Codebase Index tools →

Read tools on other servers

M-Team MCP Server get_torrent_detail YouTube MCP Server search_channel Android Forensics ADB MCP Server parse_browser_history 0xarchive web3_challenge

Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Data exfiltration → How read access becomes an exfiltration channel when chained with untrusted content.
MCP token cost → What connecting this server costs in context-window tokens on every request.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about search_codebase

What does the search_codebase tool do? +

Search your codebase using natural language queries. Returns relevant code snippets with file paths and line numbers. It is categorised as a Read tool in the MCP Codebase Index MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on search_codebase? +

Register the MCP Codebase Index 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 Codebase Index. Nothing to install.

What risk level is search_codebase? +

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

Can I rate-limit search_codebase? +

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.

How do I block search_codebase completely? +

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.

What MCP server provides search_codebase? +

search_codebase is provided by the MCP Codebase Index MCP server (ngotaico/mcp-codebase-index). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every MCP Codebase Index tool call.

Start from MCP Codebase Index, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →