Bug: Anthropic Chat Model node fails on n8n Cloud 2.10.1 — credential works via HTTP Request

[JulienPharma]

Describe the problem/error/question

The native Anthropic Chat Model node (lmChatAnthropic v1.3) fails to authenticate with a valid Anthropic API key. Both the credential test and actual workflow execution fail. However, the exact same API key works perfectly when used via an HTTP Request node calling the same Anthropic API endpoint. This confirms the issue is within n8n's Anthropic node implementation, not with the API key or Anthropic's service.

This appears to be the same issue reported in:

• Anthropic account credentials won't authenticate #15646
• Anthropic API Key Bad Request #13262

What is the error message (if any)?

Credential test error:
"Couldn't connect with these settings — The resource you are requesting could not be found"

Workflow execution error:
"Error in sub-node 'Anthropic Chat Model'"

NodeOperationError: Error in sub-node Anthropic Chat Model
  at ExecuteContext.getInputConnectionData

Node type: @n8n/n8n-nodes-langchain.lmChatAnthropic
Node version: 1.3 (Latest)

Please share your workflow/screenshots/recording

Failing workflow (native Anthropic node):

{
  "name": "Test Anthropic Credential",
  "nodes": [
    {
      "parameters": {},
      "id": "chat-trigger",
      "name": "When chat message received",
      "type": "@n8n/n8n-nodes-langchain.chatTrigger",
      "typeVersion": 1.1,
      "position": [0, 0]
    },
    {
      "parameters": {},
      "id": "llm-chain",
      "name": "AI Agent",
      "type": "@n8n/n8n-nodes-langchain.chainLlm",
      "typeVersion": 1.4,
      "position": [220, 0]
    },
    {
      "parameters": {
        "model": "claude-sonnet-4-20250514",
        "options": {
          "maxTokensToSample": 1024
        }
      },
      "id": "anthropic-model",
      "name": "Anthropic Chat Model",
      "type": "@n8n/n8n-nodes-langchain.lmChatAnthropic",
      "typeVersion": 1.3,
      "position": [220, 220]
    }
  ],
  "connections": {
    "When chat message received": {
      "main": [[{"node": "AI Agent", "type": "main", "index": 0}]]
    },
    "Anthropic Chat Model": {
      "ai_languageModel": [[{"node": "AI Agent", "type": "ai_languageModel", "index": 0}]]
    }
  }
}

Working workflow (HTTP Request with same API key):

{
  "name": "Test Anthropic via HTTP",
  "nodes": [
    {
      "parameters": {},
      "id": "chat-trigger",
      "name": "When chat message received",
      "type": "@n8n/n8n-nodes-langchain.chatTrigger",
      "typeVersion": 1.1,
      "position": [0, 0]
    },
    {
      "parameters": {
        "method": "POST",
        "url": "https://api.anthropic.com/v1/messages",
        "sendHeaders": true,
        "headerParameters": {
          "parameters": [
            {"name": "x-api-key", "value": "sk-ant-api03-REDACTED"},
            {"name": "anthropic-version", "value": "2023-06-01"},
            {"name": "content-type", "value": "application/json"}
          ]
        },
        "sendBody": true,
        "specifyBody": "json",
        "jsonBody": "={{ JSON.stringify({ model: \"claude-sonnet-4-20250514\", max_tokens: 1024, messages: [{ role: \"user\", content: $json.chatInput }] }) }}"
      },
      "id": "http-request",
      "name": "Call Claude API",
      "type": "n8n-nodes-base.httpRequest",
      "typeVersion": 4.2,
      "position": [220, 0]
    }
  ],
  "connections": {
    "When chat message received": {
      "main": [[{"node": "Call Claude API", "type": "main", "index": 0}]]
    }
  }
}

Share the output returned by the last node

HTTP Request node output (proving key works):

{
  "model": "claude-sonnet-4-20250514",
  "id": "msg_01Ax8Lbb9vX7T9HnTac78UFg",
  "type": "message",
  "role": "assistant",
  "content": [{"type": "text", "text": "Hello! I'm working correctly. How can I help you today?"}],
  "stop_reason": "end_turn",
  "usage": {
    "input_tokens": 8,
    "output_tokens": 17
  }
}

Debug info

What I verified:

• API key format: valid sk-ant-api03-... key
• Base URL: https://api.anthropic.com
• Anthropic credit balance: $9.99 USD active
• Key has no spaces or line breaks
• Fresh key generated and tested

core

• n8nVersion: 2.10.1
• platform: docker (cloud)
• nodeJsVersion: 24.13.1
• nodeEnv: production
• database: sqlite
• executionMode: regular
• concurrency: 5
• license: enterprise (sandbox)

storage

• success: all
• error: all
• progress: false
• manual: true
• binaryMode: filesystem

pruning

• enabled: true
• maxAge: 168 hours
• maxCount: 2500 executions

client

• userAgent: mozilla/5.0 (macintosh; intel mac os x 10_15_7) applewebkit/537.36 (khtml, like gecko) chrome/145.0.0.0 safari/537.36
• isTouchDevice: false
• Generated at: 2026-02-26T18:23:19.696Z

[n8n-assistant]

Hey @JulienPharma,

Thank you for reaching out! We’ve received your issue and are looking into it. To help us track this internally, we’ve created a Linear ticket with the reference: "GHC-7020".

We’ll keep you updated as we make progress, but if you have any additional details or context to share, feel free to add them here - it’s always helpful!

Thanks for your patience and for bringing this to our attention.

---

For INTERNAL use only: GHC-7020

[dev-kinsukghosh]

ok @JulienPharma

[dev-kinsukghosh]

iam checking it out

[dev-kinsukghosh]

Tested on cloud like n8n compose file given by n8n team members and same version user provided

i could not test it with http node tho there def a issue with anthropic node #triage:complete

[BardonNathan]

I had the same issue. I found n8n model list is outdated by enabling debug logging.
The Anthropic Chat Model node try to use claude-3-haiku-20240307 to test creds which is deprecated since February 19, 2026 according to the documentation.

I ignored the issue and try a simple workflow while forcing to use the model claude-haiku-4-5-20251001 (found on the doc) and it works well ! 🎉

[krisn0x]

Hey,

Thank you for bringing this up! It looks like this issue is a duplicate of #XX_insert_id_XX, You can follow that issue where we’re already tracking progress and updates. To keep things organized, we’ll close this issue and continue the discussion over there.

If you have any additional details or context that might help, please feel free to add them to the original issue. Your input is always appreciated!

Thanks again for your contribution, and let us know if there’s anything else we can assist with.

Best regards,
n8n Team

[ReevesL]

@krisn0x : I'm not sure these are entirely the same. It looks like issue #26637 is about unit tests failing and this issue is about an end user's credentials failing when adding new credentials via the n8n UI. See proposed fix here: #26568

Thanks,
Reeves