Enum Message 

#[non_exhaustive]
pub enum Message {
    System {
        id: String,
        meta: MessageMeta,
        content: String,
    },
    User {
        id: String,
        meta: MessageMeta,
        content: Vec<ContentPart>,
    },
    Assistant {
        id: String,
        meta: MessageMeta,
        content: Vec<AssistantContent>,
    },
    Tool {
        id: String,
        meta: MessageMeta,
        tool_call_id: String,
        content: Vec<ContentPart>,
    },
}

A single message in the conversation history.

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.

System

Fields

id: String

meta: MessageMeta

content: String

User

Fields

id: String

meta: MessageMeta

content: Vec<ContentPart>

Assistant

Fields

id: String

meta: MessageMeta

content: Vec<AssistantContent>

Tool

Fields

id: String

meta: MessageMeta

tool_call_id: String

content: Vec<ContentPart>

Implementations

impl Message

pub fn system(content: &str) -> Message

pub fn user(content: &str) -> Message

pub fn assistant(content: &str) -> Message

pub fn assistant_with_tool_call(content: &str, call: ToolCallRef) -> Message

pub fn assistant_with_tool_calls( content: &str, calls: Vec<ToolCallRef>, ) -> Message

pub fn tool_result(id: impl Into<String>, content: &str) -> Message

pub fn user_with_parts(parts: Vec<ContentPart>) -> Message

Construct a User message from an arbitrary list of content parts. Order is preserved on the wire.

pub fn tool_result_with_parts( tool_call_id: impl Into<String>, parts: Vec<ContentPart>, ) -> Message

Construct a Tool-result message from an arbitrary list of content parts.

pub fn user_with_image_base64( prompt: &str, media_type: impl Into<String>, data: impl Into<String>, ) -> Message

Convenience: User message with a text prompt followed by a base64 image. If prompt is empty, the text part is omitted.

pub fn user_with_image_url(prompt: &str, url: impl Into<String>) -> Message

Convenience: User message with a text prompt followed by a URL image. If prompt is empty, the text part is omitted.

pub fn tool_result_with_image_base64( tool_call_id: impl Into<String>, text: &str, media_type: impl Into<String>, data: impl Into<String>, ) -> Message

Convenience: Tool result with a leading text followed by a base64 image. If text is empty, the text part is omitted.

pub fn tool_result_with_image_url( tool_call_id: impl Into<String>, text: &str, url: impl Into<String>, ) -> Message

Convenience: Tool result with a leading text followed by a URL image. If text is empty, the text part is omitted.

pub fn user_with_document_base64( prompt: &str, media_type: impl Into<String>, data: impl Into<String>, ) -> Message

Convenience: User message with a text prompt followed by a base64 document. If prompt is empty, the text part is omitted.

pub fn user_with_document_url(prompt: &str, url: impl Into<String>) -> Message

Convenience: User message with a text prompt followed by a URL document. If prompt is empty, the text part is omitted.

pub fn user_with_pdf_base64(prompt: &str, data: impl Into<String>) -> Message

Hardcodes application/pdf as the media type. If prompt is empty, the text part is omitted.

pub fn user_with_pdf_url(prompt: &str, url: impl Into<String>) -> Message

Convenience: User message with a text prompt followed by a PDF URL. If prompt is empty, the text part is omitted.

pub fn role(&self) -> Role

pub fn id(&self) -> &String

pub fn meta(&self) -> &MessageMeta

pub fn meta_mut(&mut self) -> &mut MessageMeta

pub fn text(&self) -> String

All text content concatenated. Non-text parts are skipped.

pub fn approx_visible_chars(&self) -> usize

Approximate number of prompt-visible characters for token estimation.

Includes all currently-known assistant block types so estimators do not undercount when non-Text blocks (e.g. Reasoning, Compaction) are present. Unknown future block variants fall back to serialized length.

pub fn tool_calls(&self) -> Vec<&ToolCallRef>

Tool call references on an assistant message; empty for other roles.

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

For Tool role messages, the id of the tool call this is a result for.

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<(), Error>

Formats the value using the given formatter.

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

fn deserialize<__D>( __deserializer: __D, ) -> Result<Message, <__D as Deserializer<'de>>::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 as Serializer>::Ok, <__S as Serializer>::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for Message