mcp_set_value · Me MCP: Risk & Policy

WHAT IT DOES

What mcp_set_value does on Memcp

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

WHY IT NEEDS A POLICY

Why mcp_set_value needs a policy

The tool name 'set_value' combined with the server's purpose of storing information persistently in SQLite indicates this creates or modifies data in the database. This is a reversible Write operation.

From the tool's definition Tool name 'mcp_set_value' indicates data modification. Server uses 'local SQLite database' for storage. Sibling tool 'mcp_get_value' confirms read/write pattern. Description is empty, limiting definitive assessment.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

mcp_set_value Rate-limited

mcp_set_value 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": {
    "mcp_set_value": {
      "limits": [
        {
          "counter": "mcp_set_value_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 Memcp, so you can run agents against it safely.

FAQ

Questions about mcp_set_value

What does the mcp_set_value tool do? +

mcp_set_value. It is categorised as a Write tool in the Memcp MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on mcp_set_value? +

Register the Me MCP server in PolicyLayer and add a rule for mcp_set_value: 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 Memcp. Nothing to install.

What risk level is mcp_set_value? +

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

Can I rate-limit mcp_set_value? +

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

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

mcp_set_value is provided by the Me MCP server (moshez/memcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.