Prompts

Synaptic provides two levels of prompt template:

• PromptTemplate -- simple string interpolation with {{ variable }} syntax. Takes a HashMap<String, String> and returns a rendered String.
• ChatPromptTemplate -- produces a Vec<Message> from a sequence of MessageTemplate entries. Each entry can be a system, human, or AI message template, or a Placeholder that injects an existing list of messages.

Both template types implement the Runnable trait, so they compose directly with chat models, output parsers, and other runnables using the LCEL pipe operator (|).

Quick Example

use synaptic::prompts::{PromptTemplate, ChatPromptTemplate, MessageTemplate};

// Simple string template
let pt = PromptTemplate::new("Hello, {{ name }}!");
let mut values = std::collections::HashMap::new();
values.insert("name".to_string(), "world".to_string());
assert_eq!(pt.render(&values).unwrap(), "Hello, world!");

// Chat message template (produces Vec<Message>)
let chat = ChatPromptTemplate::from_messages(vec![
    MessageTemplate::system("You are a {{ role }} assistant."),
    MessageTemplate::human("{{ question }}"),
]);

Sub-Pages

• Chat Prompt Template -- build multi-message prompts with variable interpolation and placeholders
• Few-Shot Prompting -- inject example conversations for few-shot learning