Struct Message 

pub struct Message {
    pub id: String,
    pub role: Role,
    pub content: Content,
    pub tool_calls: Vec<ToolCall>,
    pub tool_call_id: Option<String>,
    pub name: Option<String>,
    pub usage: Option<TokenUsage>,
}

Message type for LLM conversations.

Used in agent workflows with message-based state.

Fields

id: String

Unique message identifier

role: Role

Message role (system, human, ai, tool)

content: Content

Message content (text or multimodal)

tool_calls: Vec<ToolCall>

Tool calls made by the AI (for AI messages)

tool_call_id: Option<String>

Tool call ID this message responds to (for tool messages)

name: Option<String>

Optional name for the message sender

usage: Option<TokenUsage>

Token usage information from LLM API responses

Implementations

impl Message

pub fn human(content: impl Into<String>) -> Self

Create a human message

pub fn ai(content: impl Into<String>) -> Self

Create an AI message

pub fn ai_with_tool_calls( content: impl Into<String>, tool_calls: Vec<ToolCall>, ) -> Self

Create an AI message with tool calls

pub fn system(content: impl Into<String>) -> Self

Create a system message

pub fn tool_result( tool_call_id: impl Into<String>, content: impl Into<String>, ) -> Self

Create a tool result message

pub const fn has_tool_calls(&self) -> bool

Check if message has tool calls

pub fn content_text(&self) -> &str

Extract text content from the message

For Content::Text, returns the text directly. For Content::MultiPart, returns the text of the first ContentPart::Text found, or an empty string if no text part exists.

pub fn remove(id: impl Into<String>) -> Self

Create a remove message sentinel

pub fn remove_all() -> Self

Create a remove-all message sentinel

This message clears the entire messages list when processed by the messages reducer. The sentinel has a special ID (REMOVE_ALL_MESSAGES) that triggers the clear operation.

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 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.