Struct UnifiedMessage 

pub struct UnifiedMessage {
    pub role: MessageRole,
    pub content: MessageContent,
    pub attributes: MessageAttributes,
    pub timestamp: DateTime<Utc>,
}

A provider-agnostic message for LLM interactions.

This is the core type of multi-llm. UnifiedMessage works across all supported providers (OpenAI, Anthropic, Ollama, LM Studio) and provides built-in support for caching hints and priority-based ordering.

Creating Messages

Use the convenience constructors for common cases:

use multi_llm::UnifiedMessage;

// Simple messages
let user = UnifiedMessage::user("What's the weather?");
let system = UnifiedMessage::system("You are a helpful assistant.");
let assistant = UnifiedMessage::assistant("The weather is sunny.");

// Semantic messages with caching defaults
let instruction = UnifiedMessage::system_instruction(
    "You are a weather bot.".to_string(),
    Some("weather-system-v1".to_string())
);

Caching

For Anthropic prompt caching (90% cost savings), use the builder methods:

use multi_llm::UnifiedMessage;

// 5-minute cache (good for development/testing)
let cached = UnifiedMessage::system("Large context...")
    .with_ephemeral_cache();

// 1-hour cache (good for production)
let long_cached = UnifiedMessage::system("Large context...")
    .with_extended_cache();

Tool Calling

For function calling workflows:

use multi_llm::UnifiedMessage;

// Assistant requests a tool call
let tool_request = UnifiedMessage::tool_call(
    "call_abc123".to_string(),
    "get_weather".to_string(),
    serde_json::json!({"city": "London"})
);

// Send the tool result back
let tool_response = UnifiedMessage::tool_result(
    "call_abc123".to_string(),
    "Sunny, 22°C".to_string(),
    false  // not an error
);

Fields

role: MessageRole

Role of this message (system, user, assistant, or tool).

content: MessageContent

Content of this message.

attributes: MessageAttributes

Attributes controlling caching, priority, and metadata.

timestamp: DateTime<Utc>

Timestamp for secondary ordering (after priority).

When messages have equal priority, they’re sorted by timestamp.

Implementations

impl UnifiedMessage

pub fn new(role: MessageRole, content: MessageContent) -> Self

Create a new message with default attributes

pub fn with_attributes( role: MessageRole, content: MessageContent, attributes: MessageAttributes, ) -> Self

Create a new message with custom attributes

pub fn system_instruction(content: String, cache_key: Option<String>) -> Self

Create a system instruction message (cacheable, high priority)

pub fn tool_definition(content: String, cache_key: Option<String>) -> Self

Create a tool definition message (cacheable, high priority)

pub fn context(content: String, cache_key: Option<String>) -> Self

Create a context message (cacheable, medium priority)

pub fn history(role: MessageRole, content: String) -> Self

Create a history message (cacheable, lower priority)

pub fn current_user(content: String) -> Self

Create a current user message (not cacheable, lowest priority)

pub fn tool_call(id: String, name: String, arguments: Value) -> Self

Create a tool call message

pub fn tool_result( tool_call_id: String, content: String, is_error: bool, ) -> Self

Create a tool result message

pub fn simple(role: MessageRole, content: impl Into<String>) -> Self

Create a simple text message

pub fn user(content: impl Into<String>) -> Self

Create a simple user message

pub fn assistant(content: impl Into<String>) -> Self

Create a simple assistant message

pub fn system(content: impl Into<String>) -> Self

Create a simple system message

pub fn with_ephemeral_cache(self) -> Self

Mark this message for ephemeral caching (5-minute TTL)

pub fn with_extended_cache(self) -> Self

Mark this message for extended caching (1-hour TTL)

Trait Implementations

impl Clone for UnifiedMessage

fn clone(&self) -> UnifiedMessage

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for UnifiedMessage

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for UnifiedMessage

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for UnifiedMessage

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

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 UnifiedMessage