lock_file · Unfakable MCP: Risk & Policy

WHAT IT DOES

What lock_file does on Unfakable

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

WHY IT NEEDS A POLICY

Why lock_file needs a policy

This tool creates and persists new cryptographic lock records on a blockchain-anchored verification service. While the local file itself is not modified and the action is technically reversible at Unfakable's discretion, the tool's primary effect is to write/create a new permanent record in an external immutable system, binding a file hash to blockchain state.

From the tool's definition Creates a new Bitcoin-anchored lock by submitting a file fingerprint with context binding to Unfakable, returning a permanent verifier handle. The tool irreversibly registers data on an external blockchain-anchored service.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

lock_file Rate-limited

lock_file 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": {
    "lock_file": {
      "limits": [
        {
          "counter": "lock_file_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 Unfakable, so you can run agents against it safely.

FAQ

Questions about lock_file

What does the lock_file tool do? +

Create a new Bitcoin-anchored lock for a local file. Computes SHA-256 locally (file never uploads), submits the fingerprint with context binding to Unfakable, and returns the permanent verifier handle. Requires UNFAKABLE_API_KEY environment variable (free key: https://unfakable.ai/lock). It is categorised as a Write tool in the Unfakable MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on lock_file? +

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

What risk level is lock_file? +

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

Can I rate-limit lock_file? +

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

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

lock_file is provided by the Unfakable MCP server (unfakable/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.