# lock_file

Acquire an exclusive lock on a file path. Throws if another agent holds an active lock. Same agent re-locks refreshes the TTL.

Agent View of the PolicyLayer registry record for `lock_file`. HTML page: https://policylayer.com/tools/todos/lock-file

## Facts

- Tool: `lock_file`
- Server: Todos (`@hasna/todos`) — https://policylayer.com/tools/todos.md
- Install: `npx -y @hasna/todos`
- Homepage: git+https://github.com/hasna/todos.git
- Risk category: Write (Medium risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Rate-limited

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "lock_file",
    "arguments": {}
  }
}
```

## Why lock_file is rated Medium

This tool acquires a lock on a file path, which is a write-like operation that modifies system state (lock metadata) and can block other agents from accessing the file. It is reversible (locks expire via TTL or can be released), so it doesn't qualify as Destructive. The blast radius is medium because misuse could cause deadlocks or denial-of-service for other agents trying to access the file.

From the tool's own definition: "Acquire an exclusive lock on a file path. Throws if another agent holds an active lock. Same agent re-locks refreshes the TTL."

## Use case

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

## Recommended policy (PolicyLayer)

Verdict: **Rate-limited**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Todos:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "lock_file": {
      "limits": [
        {
          "counter": "lock_file_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on Todos (527)

- `apply_retention_cleanup` — Destructive — https://policylayer.com/tools/todos/apply-retention-cleanup.md
- `bulk_delete_tasks` — Destructive — https://policylayer.com/tools/todos/bulk-delete-tasks.md
- `cancel_agent_run` — Destructive — https://policylayer.com/tools/todos/cancel-agent-run.md
- `cancel_agent_run_dispatch` — Destructive — https://policylayer.com/tools/todos/cancel-agent-run-dispatch.md
- `cancel_dispatch` — Destructive — https://policylayer.com/tools/todos/cancel-dispatch.md
- `cleanup_artifacts` — Destructive — https://policylayer.com/tools/todos/cleanup-artifacts.md
- `delete_agent` — Destructive — https://policylayer.com/tools/todos/delete-agent.md
- `delete_artifact` — Destructive — https://policylayer.com/tools/todos/delete-artifact.md
- `delete_comment` — Destructive — https://policylayer.com/tools/todos/delete-comment.md
- `delete_label` — Destructive — https://policylayer.com/tools/todos/delete-label.md
- `delete_milestone` — Destructive — https://policylayer.com/tools/todos/delete-milestone.md
- `delete_plan` — Destructive — https://policylayer.com/tools/todos/delete-plan.md
- `delete_project` — Destructive — https://policylayer.com/tools/todos/delete-project.md
- `delete_roadmap` — Destructive — https://policylayer.com/tools/todos/delete-roadmap.md
- `delete_search_view` — Destructive — https://policylayer.com/tools/todos/delete-search-view.md
- `delete_tag` — Destructive — https://policylayer.com/tools/todos/delete-tag.md
- `delete_task` — Destructive — https://policylayer.com/tools/todos/delete-task.md
- `delete_task_list` — Destructive — https://policylayer.com/tools/todos/delete-task-list.md
- `delete_template` — Destructive — https://policylayer.com/tools/todos/delete-template.md
- `delete_watch_rule` — Destructive — https://policylayer.com/tools/todos/delete-watch-rule.md
- `machines_archive` — Destructive — https://policylayer.com/tools/todos/machines-archive.md
- `machines_delete` — Destructive — https://policylayer.com/tools/todos/machines-delete.md
- `remove_agent_run_adapter` — Destructive — https://policylayer.com/tools/todos/remove-agent-run-adapter.md
- `remove_capacity_profile` — Destructive — https://policylayer.com/tools/todos/remove-capacity-profile.md
- `remove_encryption_profile` — Destructive — https://policylayer.com/tools/todos/remove-encryption-profile.md
- `remove_local_event_hook` — Destructive — https://policylayer.com/tools/todos/remove-local-event-hook.md
- `remove_local_extension` — Destructive — https://policylayer.com/tools/todos/remove-local-extension.md
- `remove_policy_pack` — Destructive — https://policylayer.com/tools/todos/remove-policy-pack.md
- `remove_review_routing_rule` — Destructive — https://policylayer.com/tools/todos/remove-review-routing-rule.md
- `remove_runner_sandbox_profile` — Destructive — https://policylayer.com/tools/todos/remove-runner-sandbox-profile.md
- …and 497 more: https://policylayer.com/tools/todos.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

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Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=todos · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/todos