refresh_index · Code Search MCP: Risk & Policy

WHAT IT DOES

What refresh_index does on Code Search MCP

AI agents invoke refresh_index to trigger actions in Code Search MCP. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why refresh_index needs a policy

Rebuilding a symbol index is an active operation that scans a directory, processes files, and rewrites the cached index. It is not a simple read (it modifies the index state) nor purely destructive (it reconstructs rather than permanently deletes data). It falls under Execute because it triggers an external computational operation whose effects depend on the target directory argument.

From the tool's definition "Rebuild the symbol index for a directory" — actively rebuilds/reconstructs an index, triggering a potentially expensive indexing operation

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

refresh_index Rate-limited

refresh_index stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "refresh_index": {
      "limits": [
        {
          "counter": "refresh_index_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Code Search MCP, so you can run agents against it safely.

FAQ

Questions about refresh_index

What does the refresh_index tool do? +

Rebuild the symbol index for a directory. It is categorised as a Execute tool in the Code Search MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on refresh_index? +

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

What risk level is refresh_index? +

refresh_index is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit refresh_index? +

Yes. Add a rate_limit block to the refresh_index 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 refresh_index completely? +

Set action: deny in the PolicyLayer policy for refresh_index. 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 refresh_index? +

refresh_index is provided by the Code Search MCP server (llmtooling/code-search-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.