project_index · Ensemble MCP: Risk & Policy

WHAT IT DOES

What project_index does on Ensemble

AI agents use project_index to create or update resources in Ensemble — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Ensemble environment.

WHY IT NEEDS A POLICY

Why project_index needs a policy

The tool builds or refreshes an index, which is a write operation that creates or modifies stored index data. It is reversible (the index can be rebuilt), so it does not qualify as Destructive. Misuse could cause incorrect indexing of the codebase, but the blast radius is moderate since it affects search/discovery rather than source data directly.

From the tool's definition Build or refresh the codebase index for faster Scope exploration

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

project_index Rate-limited

project_index stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "project_index": {
      "limits": [
        {
          "counter": "project_index_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

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

FAQ

Questions about project_index

What does the project_index tool do? +

Build or refresh the codebase index for faster Scope exploration. It is categorised as a Write tool in the Ensemble MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on project_index? +

Register the Ensemble MCP server in PolicyLayer and add a rule for project_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 Ensemble. Nothing to install.

What risk level is project_index? +

project_index is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit project_index? +

Yes. Add a rate_limit block to the project_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 project_index completely? +

Set action: deny in the PolicyLayer policy for project_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 project_index? +

project_index is provided by the Ensemble MCP server (lynkbyte/ensemble). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.