n8n ワークフローを無制限 Claude で

n8n のワークフローはスケジュールや Webhook で無人実行され、Claude 利用が四六時中積み上がります。まさに定額無制限が活きる使い方です。

Wire the Anthropic credential

Create an Anthropic credential, paste your unlimited key (sent as x-api-key), and set the Base URL to the gateway host root — no /v1, since n8n appends /v1/messages and /v1/models itself. Attach it to the Anthropic Chat Model node feeding an AI Agent.

A trailing slash on the Base URL breaks the path, and adding /v1 yourself produces a doubled /v1/v1 — host root only.

Fixing 'n8n Claude API key not working'

This common error is usually not a bad key. n8n's credential test calls GET {BaseURL}/v1/models; a gateway without that endpoint fails the test even when chat works. The unlimited gateway implements /v1/models, so the credential saves.

The other cause is auth scheme — n8n sends x-api-key, so a Bearer-only gateway 401s. Use Add Custom Header to send Bearer if required.

Why unattended automation needs unlimited

A single workflow that classifies every inbound ticket, or summarizes a feed hourly, fires Claude calls continuously with nobody watching. Multiply that across a dozen automations and the volume is both large and unpredictable.

On per-token billing a runaway loop at 3am is a real risk. Flat-rate unlimited makes the bill the same whether your workflows make a hundred calls or a hundred thousand — you can schedule everything without fear.

Scaling your automations

Because the cost is fixed, you can add AI steps to workflows you previously kept rule-based, run them more often, and let agents branch into sub-tasks.

One unlimited key covers every Anthropic node across all your workflows for the plan's duration.

# n8n -> Credentials -> Anthropic
# API Key:  <key>
# Base URL: https://claudeapikey.dev   (host root, NO /v1)
# Attach to: Anthropic Chat Model -> AI Agent

FAQ

How do I connect unlimited Claude to n8n?
Create an Anthropic credential with your unlimited key and set the Base URL to the gateway host root (no /v1). Attach it to the Anthropic Chat Model node.

Why is my n8n Claude key 'not working'?
Its credential test calls /v1/models; a gateway lacking it fails the test even though chat works. The unlimited gateway implements it. Bearer-vs-x-api-key mismatch is the other cause.

Why use unlimited for n8n?
Workflows run unattended on schedules and webhooks, generating continuous unpredictable volume. Flat-rate unlimited covers it for a fixed price.

Does the Base URL include /v1?
No — host root only; n8n appends the paths.