Chat Prompt Template

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Node Details

• Name: chatPromptTemplate
• Type: ChatPromptTemplate
• Version: 2.0
• Category: Prompts

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Base Classes

• ChatPromptTemplate
• BasePromptTemplate

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Parameters

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Inputs

1. System Message (Required)
   • Type: string
   • Description: Initial system message that sets the context or role for the AI
   • Example: "You are a helpful assistant that translates {input_language} to {output_language}."
2. Human Message (Required)
   • Type: string
   • Description: Human message prompt added at the end of the message sequence
   • Example: “{text}”
3. Format Prompt Values (Optional)
   • Type: JSON
   • Description: Variables specification for use in prompts
   • Example:
     Copy

     {
       "input_language": "English",
       "output_language": "Spanish"
     }
     

4. Messages History (Optional)
   • Type: Tabs
   • Default: messageHistoryCode
   • Description: Additional messages after System Message for few-shot examples
   • Tabs:
     • Add Messages (Code)
       • Type: code
       • Description: Custom message history using JavaScript code

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Functionality

1. Message Management
   • System message handling
   • Human message formatting
   • History integration
   • Variable substitution
2. Template Processing
   • Dynamic execution
   • Code sandboxing
   • Context building
   • Error handling

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Use Cases

1. Conversational AI
   • Customer service
   • Language translation
   • Task assistance
   • Knowledge base queries
2. Context Management
   • Role definition
   • Few-shot learning
   • Conversation history
   • Dynamic responses

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Integration Notes

• Uses @langchain/core/prompts
• Supports JavaScript execution
• Handles JSON parsing
• Implements sandboxed environments

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Best Practices

1. System Message Design
   • Clear instructions
   • Specific role definition
   • Consistent context
   • Appropriate constraints
2. Message History
   • Relevant examples
   • Progressive complexity
   • Clear structure
   • Safe code execution
3. Variable Management
   • Clear naming
   • Type consistency
   • Error handling
   • Default values

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Input/Output

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Input

• The node takes in the defined parameters (system message, human message, prompt values, and optional message history).
• If message history code is provided, it is executed in a sandboxed environment.

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Output

• The node outputs a ChatPromptTemplate object that includes:
  • A system message
  • Optional message history (if provided and valid)
  • A human message

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Usage

1. Setting up consistent system instructions across multiple interactions.
2. Defining a standard format for human inputs.
3. Incorporating few-shot examples or specific conversation context through the message history feature.
4. Allowing for dynamic prompt creation by using variables in the system and human messages.

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Implementation Details

• The node uses the @langchain/core/prompts library to create the chat prompt template.
• It supports dynamic execution of JavaScript code for creating custom message histories.
• The node handles JSON parsing for prompt values, allowing for variable substitution in the prompts.
• Error handling is implemented for invalid JSON or message history code execution.

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Notes

• The message history feature uses a sandboxed VM for executing user-provided code, ensuring safety and isolation.
• The node is designed to be flexible, allowing for both simple prompt creation and more complex setups with custom message histories.
• It integrates with a database (likely for storing or retrieving additional context), as indicated by the use of DataSource and IDatabaseEntity.