Struct ChatMessage

Source

pub struct ChatMessage {
    pub role: ChatRole,
    pub content: Vec<ContentBlock>,
}

Expand description

A single message in a conversation.

Use the convenience constructors for common cases:

use llm_stack::ChatMessage;

let user  = ChatMessage::user("What is 2+2?");
let asst  = ChatMessage::assistant("4");
let sys   = ChatMessage::system("You are a math tutor.");
let tool  = ChatMessage::tool_result("call_123", "4");

For multi-block content (images, multiple tool results), construct the content vec directly.

Fields§

§role: ChatRole

Who sent this message.

§content: Vec<ContentBlock>

The content blocks that make up the message body.

Implementations§

Source §

impl ChatMessage

Source

pub fn text(role: ChatRole, text: impl Into<String>) -> Self

Creates a message with a single ContentBlock::Text block.

Source

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

Shorthand for a ChatRole::User text message.

Source

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

Shorthand for a ChatRole::Assistant text message.

Source

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

Shorthand for a ChatRole::System text message.

Source

pub fn tool_result( tool_call_id: impl Into<String>, content: impl Into<String>, ) -> Self

Creates a ChatRole::Tool message with a single successful ToolResult.

Use ChatMessage::tool_error when the tool invocation failed.

Source

pub fn tool_error( tool_call_id: impl Into<String>, content: impl Into<String>, ) -> Self

Creates a ChatRole::Tool message indicating the tool call failed. The content should describe the error.

Source

pub fn is_empty(&self) -> bool

Returns true if the message has zero content blocks.

This checks the block count only — a message containing a single ContentBlock::Text("") returns false. Use this to detect structurally empty messages (no blocks at all).

Source

pub fn to_json(&self) -> Result<Value, Error>

Serializes the message to a stable JSON format.

This format is documented and versioned for persistence use cases (conversation history, checkpointing, etc.). The format is guaranteed to be backward compatible within the same major version.

§Stability Guarantees

Field names are stable within major versions
New optional fields may be added in minor versions
The output is deterministic for the same input

§Example

use llm_stack::ChatMessage;

let msg = ChatMessage::user("Hello, world!");
let json = msg.to_json().expect("serialization should succeed");
assert!(json["content"][0]["text"].as_str() == Some("Hello, world!"));

Source

pub fn from_json(value: &Value) -> Result<Self, Error>

Deserializes a message from the stable JSON format.

Accepts JSON produced by to_json. This method is the inverse of to_json and maintains roundtrip fidelity.

§Example

use llm_stack::ChatMessage;
use serde_json::json;

let json = json!({
    "role": "User",
    "content": [{"text": "Hello!"}]
});
let msg = ChatMessage::from_json(&json).expect("valid message");
assert_eq!(msg.role, llm_stack::ChatRole::User);

Source

pub fn from_json_owned(value: Value) -> Result<Self, Error>

Deserializes a message from the stable JSON format, consuming the value.

This is more efficient than from_json when you have an owned Value that you don’t need afterward, as it avoids cloning.

§Example

use llm_stack::ChatMessage;
use serde_json::json;

let json = json!({
    "role": "User",
    "content": [{"text": "Hello!"}]
});
let msg = ChatMessage::from_json_owned(json).expect("valid message");
assert_eq!(msg.role, llm_stack::ChatRole::User);