insert_blob · MemoDB MCP Server MCP: Risk & Policy

WHAT IT DOES

What insert_blob does on MemoDB MCP Server

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

WHY IT NEEDS A POLICY

Why insert_blob needs a policy

The tool creates or stores conversation data ('insert') which is a reversible modification operation. It does not execute arbitrary code, delete data, move money, or perform read-only queries. Severity is medium because inserting conversation data could expand storage or create unwanted records, but the impact is limited to that specific blob and reversible via deletion.

From the tool's definition Tool name 'insert_blob' with description 'Insert conversation data' indicates creation of new data records without irreversible deletion.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

insert_blob Rate-limited

insert_blob 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": {
    "insert_blob": {
      "limits": [
        {
          "counter": "insert_blob_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 MemoDB MCP Server, so you can run agents against it safely.

FAQ

Questions about insert_blob

What does the insert_blob tool do? +

Insert conversation data. It is categorised as a Write tool in the MemoDB 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 insert_blob? +

Register the MemoDB MCP Server MCP server in PolicyLayer and add a rule for insert_blob: 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 MemoDB MCP Server. Nothing to install.

What risk level is insert_blob? +

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

Can I rate-limit insert_blob? +

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

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

insert_blob is provided by the MemoDB MCP Server MCP server (wuyunmei/momedb-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.