rebuild_index · Claude Memory MCP Server MCP: Risk & Policy

WHAT IT DOES

What rebuild_index does on Claude Memory MCP Server

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

WHY IT NEEDS A POLICY

Why rebuild_index needs a policy

Rebuilding an index is a reversible write operation—it reconstructs existing metadata structures without permanently destroying data. While it modifies system state (index.json), the original memory files remain intact and the operation is recoverable. This is more severe than a simple Read (which would just check the index) but less severe than Destructive (which would irreversibly remove memories).

From the tool's definition Tool 'rebuild_index' performs a structural operation that modifies index.json by reconstructing it from source data. This is a maintenance operation that creates/updates index metadata, not a destructive deletion.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

rebuild_index Rate-limited

rebuild_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": {
    "rebuild_index": {
      "limits": [
        {
          "counter": "rebuild_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 Claude Memory MCP Server, so you can run agents against it safely.

FAQ

Questions about rebuild_index

What does the rebuild_index tool do? +

Rebuild the memory index from actual memory files. Use this if index.json is corrupted. It is categorised as a Write tool in the Claude Memory MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on rebuild_index? +

Register the Claude Memory MCP Server MCP server in PolicyLayer and add a rule for rebuild_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 Claude Memory MCP Server. Nothing to install.

What risk level is rebuild_index? +

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

Can I rate-limit rebuild_index? +

Yes. Add a rate_limit block to the rebuild_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 rebuild_index completely? +

Set action: deny in the PolicyLayer policy for rebuild_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 rebuild_index? +

rebuild_index is provided by the Claude Memory MCP Server MCP server (seongcheoljeon/claudememorymcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.