append_log · Scratchpad MCP: Risk & Policy

WHAT IT DOES

What append_log does on Scratchpad

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

WHY IT NEEDS A POLICY

Why append_log needs a policy

The tool adds new entries to a log file but does not modify or delete existing data. It is a write operation (creating new log entries) that is reversible in the sense that log entries can be deleted separately. The append-only nature limits blast radius — misuse results in unwanted log entries, not data loss or code execution.

From the tool's definition Append a single entry to a log at the given path. Logs are append-only

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

append_log Rate-limited

append_log 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": {
    "append_log": {
      "limits": [
        {
          "counter": "append_log_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 Scratchpad, so you can run agents against it safely.

FAQ

Questions about append_log

What does the append_log tool do? +

Append a single entry to a log at the given path. Logs are append-only —. It is categorised as a Write tool in the Scratchpad MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on append_log? +

Register the Scratchpad MCP server in PolicyLayer and add a rule for append_log: 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 Scratchpad. Nothing to install.

What risk level is append_log? +

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

Can I rate-limit append_log? +

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

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

append_log is provided by the Scratchpad MCP server (mikepressure/scratchpad-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.