Queue Inspector

npm CI

An MCP server that lets an agent inspect and operate Redis-backed job queues. It speaks to three backends today, Asynq (Go) and BullMQ (Node) and Sidekiq (Ruby): per-state counts, individual job detail, and moving jobs between states — six tools over stdio, with a --read-only mode that drops the mutating ones entirely.

When a queue misbehaves in production, the useful questions are about jobs, not keys: how many tasks are stuck in retry, what error a specific job failed with, whether a dead job can be requeued. A generic Redis MCP server shows you keys and raw values; this one understands Asynq's protobuf task messages and BullMQ's state structures, and Sidekiq's inline job JSON, so an agent can answer those questions directly.

What this looks like from the agent side. The tool output below is recorded, not mocked: a local Redis seeded with real Asynq tasks, an SMTP relay down, and one delivery out of attempts.

> smtp relay was down earlier, it's back now - did we strand anything in the default queue?

⏺ queues - queue_stats (MCP)(queue: "default")
  ⎿  { "queue": "default", "backend": "asynq", "states": { "pending": 0, "active": 0,
       "scheduled": 6, "retry": 38, "archived": 1, "completed": 57 } }

⏺ 38 tasks are stuck in retry and one is archived. Sampling the retries to see why.
⏺ queues - list_jobs (MCP)(queue: "default", state: "retry", limit: 3)
  ⎿  { …, "count": 3, "jobs": [
       { "id": "46c6ba86-…", "type": "email:deliver", …, "attempts": 5, "maxRetries": 25,
         "lastError": "dial tcp 127.0.0.1:2525: connect: connection refused" }, … ] }

⏺ Every sampled retry is email:deliver failing to reach the relay; those re-run on their own
  now that it's back. The archived task is out of attempts — it never will.
⏺ queues - list_jobs (MCP)(queue: "default", state: "archived", limit: 1)
  ⎿  { …, "count": 1, "jobs": [ { "id": "814cc556-04a8-4923-8de5-71a661c6063c", … } ] }
⏺ queues - get_job (MCP)(queue: "default", id: "814cc556-04a8-4923-8de5-71a661c6063c")
  ⎿  { …, "type": "email:deliver", "state": "archived", …, "attempts": 8, "maxRetries": 8,
       …, "fullError": "dial tcp 127.0.0.1:2525: connect: connection refused",
       "timestamps": { …, "lastFailedAt": "2026-07-10T14:01:40.000Z", … },
       "payload": "{\"to\":\"[email protected]\",\"template\":\"receipt\"}", … }

⏺ A receipt email that burned all 8 attempts during the outage. Requeuing it.
⏺ queues - retry_job (MCP)(queue: "default", id: "814cc556-04a8-4923-8de5-71a661c6063c")
  ⎿  { "ok": true, "message": "asynq task 814cc556-04a8-4923-8de5-71a661c6063c moved to
       pending in queue \"default\"" }

⏺ queues - queue_stats (MCP)(queue: "default")
  ⎿  { "queue": "default", "backend": "asynq", "states": { "pending": 1, "active": 0,
       "scheduled": 6, "retry": 38, "archived": 0, "completed": 57 } }
⏺ The receipt is back in pending. The other 38 will re-run as their backoff timers come due.

Background: I wrote up the design decisions behind this — why jobs, not keys, and the read-only posture — on my blog.

Architecture

---
config:
  look: handDrawn
---
flowchart LR
    A["AI agent"] -->|"MCP · stdio"| M["queue-inspector-mcp"]
    M --> B1["Asynq adapter<br/>protobuf msg"]
    M --> B2["BullMQ adapter<br/>state by zset"]
    M --> B3["Sidekiq adapter<br/>job JSON in lists + zsets"]
    B1 -->|ioredis| R[("Redis")]
    B2 -->|ioredis| R
    M -.->|"--read-only<br/>drops mutating tools"| G{{"prod-safe"}}

The server speaks MCP over stdio to the agent and talks to Redis through per-backend adapters that understand each library's Redis key layout — Asynq's protobuf task messages, BullMQ's state-by-membership sorted sets, and Sidekiq's inline job JSON — instead of treating Redis as a bag of keys.

Why an MCP server instead of the CLI

Asynq ships a CLI, and redis-cli can read anything. But wiring a CLI into an agent means giving the agent a shell. The tools here return structured JSON the model can reason over rather than aligned text to re-parse; they work in clients that have no shell, like Claude Desktop; and read-only is enforced by construction — under --read-only the mutating tools are not in tools/list at all, which is a stronger guarantee than a confirmation prompt a model can talk its way past.

Install

Requires Node.js 18 or newer and a reachable Redis.

npm install -g queue-inspector-mcp
# or run without installing:
npx queue-inspector-mcp

Configure

The server talks MCP over stdio, so it works with any MCP client. Point your client at the queue-inspector-mcp binary and set REDIS_URL.

Claude Desktop (claude_desktop_config.json):

{
  "mcpServers": {
    "queues": {
      "command": "npx",
      "args": ["-y", "queue-inspector-mcp"],
      "env": { "REDIS_URL": "redis://localhost:6379", "QUEUE_INSPECTOR_READ_ONLY": "1" }
    }
  }
}

Claude Code (project .mcp.json, or claude mcp add):

{
  "mcpServers": {
    "queues": {
      "command": "npx",
      "args": ["-y", "queue-inspector-mcp"],
      "env": { "REDIS_URL": "redis://localhost:6379", "QUEUE_INSPECTOR_READ_ONLY": "1" }
    }
  }
}

Both examples are read-only. To enable retry_job and delete_job, remove QUEUE_INSPECTOR_READ_ONLY.

Configuration

Variable	Default	Purpose
REDIS_URL	redis://localhost:6379	Redis connection string. Include a database number, e.g. redis://localhost:6379/2.
ASYNQ_PREFIX	asynq	Key prefix Asynq was configured with.
BULL_PREFIX	bull	Key prefix BullMQ was configured with.
SIDEKIQ_PREFIX	(none)	Key prefix Sidekiq was configured with, if namespaced.
QUEUE_INSPECTOR_BACKENDS	asynq,bullmq,sidekiq	Restrict which backends are scanned.
QUEUE_INSPECTOR_READ_ONLY	unset	Set to 1 (or pass --read-only) to omit the mutating tools.

Tools

Tool	Mutating	Behavior
list_queues	no	List every detected queue, tagged with its backend.
queue_stats	no	Count jobs per state for a queue, using the backend's own state names.
list_jobs	no	Page through jobs in one state; returns id, type, attempts, and a truncated last error.
get_job	no	Full detail for one job: payload, attempts, retry ceiling, last error, timestamps.
retry_job	yes	Move a failed or dead job back to pending/wait so it runs again.
delete_job	yes	Permanently delete a job. Active jobs are refused.

When a queue name is unique across the enabled backends, the backend argument is optional; the server resolves it. If the same name exists in more than one backend, pass backend explicitly.

Read-only mode

With --read-only or QUEUE_INSPECTOR_READ_ONLY=1, the server never registers retry_job or delete_job. The mutating tools are absent from tools/list entirely, so a client cannot call them by mistake. This is the recommended configuration for pointing an agent at a production Redis.

Backend state names

The two libraries model job lifecycles differently, so this server does not invent a shared vocabulary. It reports each backend's own state names, and each state maps to a specific Redis structure.

A job moves through these states over its lifetime (Asynq shown):

---
config:
  look: handDrawn
---
stateDiagram-v2
    [*] --> pending: enqueue
    pending --> active: worker picks up
    active --> completed: success
    active --> retry: handler error
    retry --> active: backoff elapsed
    retry --> archived: retries exhausted
    archived --> pending: retry_job
    completed --> [*]

Asynq:

State	Meaning	Redis structure
pending	Ready to run, waiting for a worker	list asynq:{q}:pending
active	Currently being processed	list asynq:{q}:active
scheduled	Enqueued for a future time	zset asynq:{q}:scheduled
retry	Failed, waiting to be retried	zset asynq:{q}:retry
archived	Retries exhausted (the "dead" state)	zset asynq:{q}:archived
completed	Finished, kept for its retention window	zset asynq:{q}:completed

BullMQ:

State	Meaning	Redis structure
waiting	Ready to run	list bull:q:wait
active	Currently being processed	list bull:q:active
delayed	Scheduled for a future time	zset bull:q:delayed
prioritized	Waiting, ordered by priority	zset bull:q:prioritized
waiting-children	Blocked on child jobs (flows)	zset bull:q:waiting-children
paused	Held while the queue is paused	list bull:q:paused
completed	Finished successfully	zset bull:q:completed
failed	Failed after exhausting attempts	zset bull:q:failed

Asynq's archived is what most people mean by a "dead" job. list_jobs returns Asynq's terminal sets in Redis (score) order and BullMQ's completed/failed sets most-recent-first.

Compatibility

• Node.js 18 or newer; any MCP client that speaks stdio. CI runs the integration suite against Redis 7.
• retry_job and delete_job run each library's own Lua, vendored verbatim with provenance headers: reprocessJob and removeJob from BullMQ 5.79.3, runTask and deleteTask from Asynq v0.25.1.
• The integration tests read and mutate jobs produced by those same versions of the real libraries — the verify/ producers lock BullMQ 5.79.3 and Asynq v0.25.1.
• BullMQ 4.x is untested: the adapter reads the v5 hash layout (attempts live in atm, where v4 used attemptsMade).

What this doesn't do

• Only Asynq and BullMQ are supported. Sidekiq, Celery, RQ and others are not.
• No web UI. This is an MCP server for programmatic use; it is not a dashboard.
• No streaming or watch. Each tool call is a point-in-time read; there is no subscription to queue events.
• retry_job and delete_job faithfully replicate each library's own mechanism rather than reimplementing it. Retry runs Asynq's Inspector.RunTask script and BullMQ's Job.retry (reprocessJob) script; delete runs Asynq's Inspector.DeleteTask script and BullMQ's Job.remove (removeJob) script. As a result the semantics match the libraries: retrying a BullMQ job applies only to failed/completed jobs and does not reset attemptsMade (matching Job.retry()); neither backend can retry or delete an active job.
• delete_job removes a single BullMQ job and does not cascade into a flow's children.
• Asynq group aggregation (the aggregating state) is not surfaced in this release.

Alternatives

• bullmq-mcp — MCP server for BullMQ only; no read-only mode.
• Workbench — a BullMQ dashboard whose MCP support is an HTTP proxy into a running Workbench instance. If you are BullMQ-only and want a UI, it is the better choice.
• Asynqmon — Asynq's web dashboard, not an MCP server; no commits since May 2024.
• mcp-redis — the official Redis MCP server; operates on keys and values, not jobs.

As of this writing there is no other MCP server that speaks Asynq — a 13.5k-star library whose dashboard has been dormant since 2024 — and none that reads both wire formats from one process.

License

MIT © Yusuf İhsan Görgel