Enum ChatMessage 

pub enum ChatMessage {
    System {
        content: String,
        timestamp: IsoString,
    },
    User {
        content: Vec<ContentBlock>,
        timestamp: IsoString,
    },
    Assistant {
        content: String,
        reasoning: AssistantReasoning,
        timestamp: IsoString,
        tool_calls: Vec<ToolCallRequest>,
    },
    ToolCallResult(Result<ToolCallResult, ToolCallError>),
    Error {
        message: String,
        timestamp: IsoString,
    },
    Summary {
        content: String,
        timestamp: IsoString,
        messages_compacted: usize,
    },
}

A message in the conversation history.

Each variant represents a different role or message type in the conversation sent to the LLM provider.

Variants

• System – The system prompt. Typically the first message in the conversation.
• User – User input, supporting multimodal content via Vec<ContentBlock>.
• Assistant – The model’s response. Includes text content, optional AssistantReasoning, and any ToolCallRequests the model made.
• ToolCallResult – The result of executing a tool call, wrapping Result<ToolCallResult, ToolCallError>.
• Error – An error message recorded in conversation history.
• Summary – A compacted summary replacing multiple earlier messages to reduce context usage. Created by Context::with_compacted_summary.

Helper methods

• is_system, is_tool_result, is_summary – Variant checks.
• timestamp – Returns the message timestamp (all variants except ToolCallResult).
• estimated_bytes – Rough byte-size estimate for pre-flight context checks.

Serialization

Uses #[serde(tag = "type", rename_all = "camelCase")] – each variant is serialized with a "type" field (e.g. {"type": "system", "content": "..."}) for use in JSON-based persistence and wire formats.

Variants

System

Fields

content: String

timestamp: IsoString

User

Fields

content: Vec<ContentBlock>

timestamp: IsoString

Assistant

Fields

content: String

reasoning: AssistantReasoning

timestamp: IsoString

tool_calls: Vec<ToolCallRequest>

ToolCallResult(Result<ToolCallResult, ToolCallError>)

Error

Fields

message: String

timestamp: IsoString

Summary

A compacted summary of previous conversation history. This replaces multiple messages with a structured summary to reduce context usage.

Fields

content: String

timestamp: IsoString

messages_compacted: usize

Number of messages that were compacted into this summary

Implementations

impl ChatMessage

pub fn is_tool_result(&self) -> bool

Returns true if this message is a tool call result

pub fn is_system(&self) -> bool

Returns true if this message is a system prompt

pub fn is_summary(&self) -> bool

Returns true if this message is a compacted summary

pub fn estimated_bytes(&self) -> usize

Rough byte-size estimate of the message content for pre-flight context checks. Not meant to be exact — just close enough to detect overflow before calling the LLM.

pub fn timestamp(&self) -> Option<&IsoString>

Returns the timestamp of this message, if it has one

Trait Implementations

impl Clone for ChatMessage

fn clone(&self) -> ChatMessage

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ChatMessage

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for ChatMessage

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for ChatMessage

fn eq(&self, other: &ChatMessage) -> 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 ChatMessage

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

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl Eq for ChatMessage

impl StructuralPartialEq for ChatMessage