Enum Message 

pub enum Message {
    System {
        content: String,
        cache_markers: Vec<SystemCacheMarker>,
    },
    Context {
        content: String,
    },
    User {
        content: String,
    },
    Multimodal {
        parts: Vec<ContentPart>,
    },
    Assistant {
        content: String,
        tool_calls: Vec<ToolCall>,
        reasoning: Option<AssistantReasoning>,
    },
    Tool {
        result: MessageToolResult,
    },
}

A message in the conversation.

Variants

System

System-level instruction (identity, rules, tool guide).

Fields

content: String

System prompt content.

cache_markers: Vec<SystemCacheMarker>

Stable prompt ranges suitable for provider-side caching.

Context

Workspace context (AGENTS.md, history summary, retrieved files).

Fields

content: String

Context content.

User

Message from the user.

Fields

content: String

The user’s message text.

Multimodal

Multimodal user message with ordered text and image parts (ADR-050).

The existing User { content: String } variant is preserved for text-only backward compatibility. This variant is additive and requires a pre-1.0 minor release for exhaustive match migration.

Fields

parts: Vec<ContentPart>

Ordered content parts — text and image interleaved in the order the user composed them.

Assistant

Response from the assistant.

Fields

content: String

The assistant’s response text.

tool_calls: Vec<ToolCall>

Tool calls requested by the assistant.

reasoning: Option<AssistantReasoning>

Provider-native reasoning blocks attached to this message.

Request-history metadata only — never display content. See ADR-034.

Tool

Result of a tool execution.

Fields

result: MessageToolResult

The tool result.

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

Equality operator ==.

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

Inequality operator !=.

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