Enum Message 

pub enum Message {
    System(SystemMessage),
    Assistant(AssistantMessage),
    User(UserMessage),
    Result(ResultMessage),
    StreamEvent(StreamEvent),
    RateLimitEvent(RateLimitEvent),
}

The top-level message type emitted by the Claude Code CLI on stdout.

Each NDJSON line deserialises into one of these variants. The "type" field drives the outer discriminant; inner subtypes are carried by nested fields.

Variants

System(SystemMessage)

A system-level message (e.g., session initialisation, tool list).

Assistant(AssistantMessage)

A message produced by the assistant (Claude).

User(UserMessage)

A user turn in the conversation.

Result(ResultMessage)

The final result message containing cost and usage summary.

StreamEvent(StreamEvent)

A streaming event emitted during tool execution or other async operations.

RateLimitEvent(RateLimitEvent)

A rate limit status event emitted after API calls.

Implementations

impl Message

pub fn session_id(&self) -> Option<&str>

Returns the session ID if present on this message variant.

pub fn is_error_result(&self) -> bool

Returns true if this is a Message::Result that indicates an error.

pub fn is_stream_event(&self) -> bool

Returns true if this is a Message::StreamEvent.

pub fn assistant_text(&self) -> Option<String>

Extract text content from an Message::Assistant message, joining all ContentBlock::Text blocks with newlines.

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