Enum Message 

#[non_exhaustive]
pub enum Message {
    User {
        blocks: Vec<UserBlock>,
    },
    Assistant {
        blocks: Vec<AssistantBlock>,
    },
}

One turn in the conversation history exchanged with a provider.

Message is the wire shape: every provider adapter maps this enum to its own block model (Anthropic Messages, OpenAI Chat Completions, etc.). Only the user and assistant roles live here — system instructions are passed separately through crate::ChatRequest::system_prompt because most providers represent them out-of-band.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

User

A user-authored turn: free text, tool results from the previous step, or a mix.

Fields

blocks: Vec<UserBlock>

Blocks rendered in order. Tool results live here because, on the wire, they are sent back to the model as user content.

Assistant

A turn produced by the model: visible text, tool calls, reasoning. Tool results are in the next User turn.

Fields

blocks: Vec<AssistantBlock>

Blocks rendered in order. Ordering is provider-significant for reasoning + tool-use chains (Anthropic extended thinking).

Implementations

impl Message

pub fn user(text: impl Into<String>) -> Message

Shorthand for a user turn containing a single text block.

pub fn assistant_text(text: impl Into<String>) -> Message

Shorthand for an assistant turn containing a single text block. Use the Message::Assistant variant directly when seeding history with tool calls or reasoning.

Trait Implementations

impl Clone for Message

fn clone(&self) -> Message

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Message

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for Message

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for Message

fn eq(&self, other: &Message) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for Message

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for Message