# concurrency-queued

A mutex tool with queue (maxConcurrent: 1, queueTimeout: 3s)

Agent View of the PolicyLayer registry record for `concurrency-queued`. HTML page: https://policylayer.com/tools/frontmcp/concurrency-queued

## Facts

- Tool: `concurrency-queued`
- Server: Frontmcp (`agentfront/frontmcp`) — https://policylayer.com/tools/frontmcp.md
- Homepage: https://github.com/agentfront/frontmcp
- Risk category: Execute (High 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": "concurrency-queued",
    "arguments": {}
  }
}
```

## Why concurrency-queued is rated High

A mutex/queue tool controls execution flow by serializing operations, enforcing concurrency limits, and timing out queued requests. This implies it triggers or gates execution of other operations, placing it in the Execute category. The blast radius is medium: misuse could cause deadlocks, starvation, or denial-of-service by exhausting the queue, but it doesn't directly destroy data or move money.

From the tool's own definition: "'A mutex tool with queue (maxConcurrent: 1, queueTimeout: 3s)' — describes a concurrency control mechanism that queues and executes operations serially"

## Use case

AI agents invoke concurrency-queued to trigger actions in Frontmcp. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.

## Recommended policy (PolicyLayer)

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

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "concurrency-queued": {
      "limits": [
        {
          "counter": "concurrency-queued_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on Frontmcp (205)

- `clear-audit-log` — Destructive — https://policylayer.com/tools/frontmcp/clear-audit-log.md
- `clear-replay-buffer` — Destructive — https://policylayer.com/tools/frontmcp/clear-replay-buffer.md
- `clear-session-notifications` — Destructive — https://policylayer.com/tools/frontmcp/clear-session-notifications.md
- `crm-reset` — Destructive — https://policylayer.com/tools/frontmcp/crm-reset.md
- `delete-vault-entry` — Destructive — https://policylayer.com/tools/frontmcp/delete-vault-entry.md
- `notes-reset` — Destructive — https://policylayer.com/tools/frontmcp/notes-reset.md
- `remove_job` — Destructive — https://policylayer.com/tools/frontmcp/remove-job.md
- `remove_workflow` — Destructive — https://policylayer.com/tools/frontmcp/remove-workflow.md
- `reset-stats` — Destructive — https://policylayer.com/tools/frontmcp/reset-stats.md
- `secret` — Destructive — https://policylayer.com/tools/frontmcp/secret.md
- `users-delete` — Destructive — https://policylayer.com/tools/frontmcp/users-delete.md
- `admin_action` — Execute — https://policylayer.com/tools/frontmcp/admin-action.md
- `admin-background-job` — Execute — https://policylayer.com/tools/frontmcp/admin-background-job.md
- `admin-only` — Execute — https://policylayer.com/tools/frontmcp/admin-only.md
- `browser_test` — Execute — https://policylayer.com/tools/frontmcp/browser-test.md
- `build-shell` — Execute — https://policylayer.com/tools/frontmcp/build-shell.md
- `cancellable-wait` — Execute — https://policylayer.com/tools/frontmcp/cancellable-wait.md
- `cold-start-test` — Execute — https://policylayer.com/tools/frontmcp/cold-start-test.md
- `concurrency-mutex` — Execute — https://policylayer.com/tools/frontmcp/concurrency-mutex.md
- `deploy_application` — Execute — https://policylayer.com/tools/frontmcp/deploy-application.md
- `emit-app-event` — Execute — https://policylayer.com/tools/frontmcp/emit-app-event.md
- `execute_job` — Execute — https://policylayer.com/tools/frontmcp/execute-job.md
- `execute_workflow` — Execute — https://policylayer.com/tools/frontmcp/execute-workflow.md
- `expensive-operation` — Execute — https://policylayer.com/tools/frontmcp/expensive-operation.md
- `experimental-agent` — Execute — https://policylayer.com/tools/frontmcp/experimental-agent.md
- `gated-acme` — Execute — https://policylayer.com/tools/frontmcp/gated-acme.md
- `load-component` — Execute — https://policylayer.com/tools/frontmcp/load-component.md
- `long-running-task` — Execute — https://policylayer.com/tools/frontmcp/long-running-task.md
- `node_runtime_tool` — Execute — https://policylayer.com/tools/frontmcp/node-runtime-tool.md
- `non-cached` — Execute — https://policylayer.com/tools/frontmcp/non-cached.md
- …and 175 more: https://policylayer.com/tools/frontmcp.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`

---

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