Enum MessageRole 

#[non_exhaustive]
pub enum MessageRole {
    System,
    User,
    Assistant,
    Tool,
}

Role of a message in an LLM conversation.

Each role has specific semantics that LLM providers understand:

• MessageRole::System: Instructions that guide the model’s behavior
• MessageRole::User: Input from the human user
• MessageRole::Assistant: Responses from the AI model
• MessageRole::Tool: Results from tool/function executions

Example

use multi_llm::{MessageRole, UnifiedMessage};

// Explicit role usage
let msg = UnifiedMessage::simple(MessageRole::User, "Hello!");

// Or use convenience constructors (preferred)
let msg = UnifiedMessage::user("Hello!");

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

System instructions that guide the model’s behavior.

System messages typically contain:

• Persona definitions (“You are a helpful assistant”)
• Behavioral constraints (“Never reveal confidential information”)
• Output format instructions (“Respond in JSON format”)

User

Input from the human user.

User messages contain the actual queries, questions, or commands that the model should respond to.

Assistant

Response from the AI assistant.

Assistant messages are typically generated by the LLM but can also be provided as conversation history or to demonstrate expected output.

Tool

Result from a tool/function execution.

Tool messages contain the output of function calls. They must reference the tool_call_id of the corresponding tool call from an assistant message.

Trait Implementations

impl Clone for MessageRole

fn clone(&self) -> MessageRole

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for MessageRole

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for MessageRole

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Display for MessageRole

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

Formats the value using the given formatter.

impl Hash for MessageRole

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for MessageRole

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

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 MessageRole

impl StructuralPartialEq for MessageRole