Claude Chat

Chat with Anthropic Claude models using the Messages API.

Overview

Sends a user message to Anthropic’s Claude chat completion API (POST /v1/messages) and returns the model’s response text. Supports Claude Opus, Sonnet, and Haiku models with configurable system prompt, temperature, top_p, top_k, and max_tokens. Each input item produces one API call. The response text is stored in a configurable output field (default: “response”) along with model name, token usage, and stop reason.

Category: AI
Tool Name: claude_chat
Version: 1

Appearance: Icon: anthropic | Color: #d4a574

Node Type

Action — processes input items and produces output

Input / Output

Direction	Port(s)
Input	Input
Output	Output, Error

Credentials

This tool requires Anthropic credentials. See the Credentials Guide for setup instructions.

Parameters

Parameter	Type	Required	Default	Description
Model	options	No	Claude Sonnet	The Claude model to use for chat completion. Always uses the latest version (auto-updated).
				Options: Claude Opus (most capable — complex analysis, coding and multi-step reasoning), Claude Sonnet (balanced — strong quality at lower cost and latency), Claude Haiku (fastest — simple tasks, classification and high-volume work). Each option tracks the current release of its tier, so the underlying model ID updates without any change to your node.
System Prompt	string	No	—	Optional system prompt to set the model’s behavior and context. Leave empty for default behavior. Supports expressions.
User Message	string	Yes	—	The user message to send to Claude. Falls back to item.message or item.prompt if empty. Supports expressions like {{ $json.text }}.
Attachment File ID	string	No	—	Optional Anthropic file_id from a previous Claude File Upload node. When set, the file is attached to the user message alongside your text. Falls back to item.fileId if empty. Supports expressions.
Attachment Type	options	No	document	How Claude should interpret the attached file. Ignored when Attachment File ID is empty.
				Options: document (PDF, plaintext, or other document file), image (JPG, PNG, GIF, or WebP image)
Options	collection	No	{}	Advanced sampling and output settings.
— Max Tokens	number	No	4096	Maximum number of tokens to generate in the response.
— Temperature	number	No	1	Sampling temperature (0-1). Lower values are more deterministic, higher values more creative.
— Top P	number	No	—	Nucleus sampling: only consider tokens with cumulative probability up to this value.
— Top K	number	No	—	Only sample from the top K most likely tokens at each step.
— Response Field Name	string	No	response	The output field name where the Claude response text will be stored.
Include Input	boolean	No	false	Whether to include the original input item fields in the output alongside the response.
Max Concurrency	number	No	10	Maximum number of items to process concurrently.

Output Data

One API call per input item, and one output item per input item. The response text lands on the field named by Response Field Name (response by default), and binary data on the input item is forwarded unchanged. With Include Input on, the original item fields are merged in alongside the result.

{
  "response": "The model's reply text",
  "model": "claude-...",
  "usage": { "input_tokens": 412, "output_tokens": 268 },
  "stopReason": "end_turn"
}

• model is the model that actually answered, as reported by Anthropic.
• usage is the token accounting Anthropic returned for the call.
• stopReason says why generation stopped — for example end_turn (finished naturally) or max_tokens (hit the Max Tokens cap).

Reference the result downstream by expression, e.g. {{ $json.response }}.

Usage Examples

• Ask Claude a question and get a text response
• Summarize text using Claude Sonnet
• Generate creative content with a system prompt
• Classify input items using Claude Haiku for speed
• Extract structured information from unstructured text

Example Configuration

Minimal — send one message per item:

{
  "type": "claude_chat",
  "parameters": {
    "userMessage": "Summarize the following article: {{ $json.articleText }}"
  }
}

Add a system prompt to control tone and format:

{
  "type": "claude_chat",
  "parameters": {
    "systemPrompt": "You are a concise technical writer. Respond only with well-structured bullet points.",
    "userMessage": "Explain the concept of backpressure in stream processing.",
    "includeInput": false,
    "maxConcurrency": 10
  }
}

Deterministic classification into a named output field:

{
  "type": "claude_chat",
  "parameters": {
    "systemPrompt": "Classify the sentiment of the input text. Respond with exactly one word: POSITIVE, NEGATIVE, or NEUTRAL.",
    "userMessage": "{{ $json.reviewText }}",
    "includeInput": true,
    "maxConcurrency": 20,
    "options": {
      "maxTokens": 10,
      "temperature": 0,
      "responseFieldName": "sentiment"
    }
  }
}

Ask a question about a file uploaded by a Claude File Upload node:

{
  "type": "claude_chat",
  "parameters": {
    "userMessage": "What are the payment terms in this contract?",
    "attachmentFileId": "{{ $json.fileId }}",
    "attachmentType": "document",
    "options": {
      "maxTokens": 1024,
      "temperature": 0.2,
      "responseFieldName": "contractAnswer"
    }
  }
}

Error Handling

Mode	Behavior
stop	Halts workflow on first error
continue	Skips failed items, passes successful ones through
errorPort	Routes failed items to Error output port

Tips

Claude Chat sends user messages to the Anthropic Messages API and returns conversational responses from Claude Opus, Sonnet, or Haiku models. Use it when a workflow step requires natural language generation, reasoning, or instruction-following with configurable temperature, top_p, top_k, and max_tokens parameters. Each input item produces one API call, and the output fields include response text, model name, token usage counts, and stop reason.