log_journal · Personal Brain MCP: Risk & Policy

WHAT IT DOES

What log_journal does on Personal Brain

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

WHY IT NEEDS A POLICY

Why log_journal needs a policy

This tool creates new journal entries in a personal database. It is a write operation (append/create) with no indication of irreversible deletion or financial impact. Misuse could result in unwanted or fabricated entries being permanently added to a personal memory store, which is a medium severity risk.

From the tool's definition Append an entry to your personal memory (journal, decision, fact, or gratitude)

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

log_journal Rate-limited

log_journal 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": {
    "log_journal": {
      "limits": [
        {
          "counter": "log_journal_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 Personal Brain, so you can run agents against it safely.

FAQ

Questions about log_journal

What does the log_journal tool do? +

Append an entry to your personal memory (journal, decision, fact, or gratitude). Embedding is generated automatically so the entry is immediately searchable. It is categorised as a Write tool in the Personal Brain MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on log_journal? +

Register the Personal Brain MCP server in PolicyLayer and add a rule for log_journal: 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 Personal Brain. Nothing to install.

What risk level is log_journal? +

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

Can I rate-limit log_journal? +

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

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

log_journal is provided by the Personal Brain MCP server (phantomts/personal-brain-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.