Enum Message 

pub enum Message {
    System {
        content: MessageContent,
        cache_control: Option<CacheControl>,
    },
    Developer {
        content: MessageContent,
        cache_control: Option<CacheControl>,
    },
    User {
        content: MessageContent,
    },
    Assistant {
        content: MessageContent,
        tool_calls: Option<Vec<ToolCall>>,
        cache_control: Option<CacheControl>,
        reasoning_content: Option<String>,
    },
    Tool {
        content: MessageContent,
        tool_call_id: String,
        is_error: bool,
    },
}

消息 —— 对话中的单条消息

使用 enum 而非 flat struct，让非法状态不可表示：

• 只有 Assistant 可以携带 tool_calls
• 只有 Tool 必须携带 tool_call_id
• 编译时就能发现角色与字段的错误组合

Variants

System

Fields

content: MessageContent

cache_control: Option<CacheControl>

Developer

Fields

content: MessageContent

cache_control: Option<CacheControl>

User

Fields

content: MessageContent

Assistant

Fields

content: MessageContent

文本内容（可能为空，如 LLM 仅发起 tool call）

tool_calls: Option<Vec<ToolCall>>

LLM 发起的工具调用

cache_control: Option<CacheControl>

缓存控制标记

reasoning_content: Option<String>

推理/思考过程（DeepSeek reasoning_content, 通义千问等）

Tool

Fields

content: MessageContent

tool_call_id: String

is_error: bool

Implementations

impl Message

pub fn system(text: &str) -> Self

pub fn developer(text: &str) -> Self

pub fn user(text: &str) -> Self

pub fn assistant(text: &str) -> Self

pub fn tool_result(tool_call_id: &str, content: &str) -> Self

pub fn tool_error(tool_call_id: &str, error: &str) -> Self

pub fn role_str(&self) -> &'static str

返回消息的角色标识字符串

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 Display for Message

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

Formats the value using the given formatter.

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.