ContextAdapter

Inject extra context into a chat request.

ContextAdapter is the trait that ContextPipeline calls to add system prompts, RAG snippets, function outputs, and other injected content to a ChatRequest before the model call.

The full file is src/context.rs.

API

#[async_trait]
pub trait ContextAdapter: Send + Sync {
    async fn adapt(&self, input: &ContextInput) -> Result<ContextOutput, ContextError>;
}

pub struct ContextInput {
    pub session: Session,
    pub user_input: String,
    pub current_messages: Vec<Message>,
}

pub struct ContextOutput {
    pub prepend_messages: Vec<Message>,
    pub append_messages: Vec<Message>,
}

Built-in adapters

• StaticAdapter — prepends a fixed system message. Use for "You are a helpful assistant."
• FunctionAdapter<F> — calls a closure to produce messages. Use for dynamic system prompts.
• RagContextAdapter — searches an embedding store and prepends relevant snippets.

See also

• RAG Context Adapter — the RAG implementation.
• ContextPipeline — the caller.