Struct CreateMessageRequest 

pub struct CreateMessageRequest {
    pub messages: Vec<SamplingMessage>,
    pub model_preferences: Option<ModelPreferences>,
    pub system_prompt: Option<String>,
    pub include_context: Option<IncludeContext>,
    pub temperature: Option<f64>,
    pub max_tokens: u32,
    pub stop_sequences: Option<Vec<String>>,
    pub tools: Option<Vec<Tool>>,
    pub tool_choice: Option<ToolChoice>,
    pub task: Option<TaskMetadata>,
    pub _meta: Option<Value>,
}

Create message request (for LLM sampling)

Fields

messages: Vec<SamplingMessage>

Messages to include in the sampling request

model_preferences: Option<ModelPreferences>

Model preferences (optional)

system_prompt: Option<String>

System prompt (optional)

include_context: Option<IncludeContext>

Include context from other servers

temperature: Option<f64>

Temperature for sampling (0.0 to 2.0)

max_tokens: u32

Maximum number of tokens to generate (required by MCP spec)

stop_sequences: Option<Vec<String>>

Stop sequences

tools: Option<Vec<Tool>>

Tools that the model may use during generation (MCP 2025-11-25 draft, SEP-1577) The client MUST return an error if this field is provided but ClientCapabilities.sampling.tools is not declared

tool_choice: Option<ToolChoice>

Controls how the model uses tools (MCP 2025-11-25 draft, SEP-1577) The client MUST return an error if this field is provided but ClientCapabilities.sampling.tools is not declared Default is { mode: "auto" }

task: Option<TaskMetadata>

Task metadata for task-augmented sampling (MCP 2025-11-25 draft, SEP-1686)

When present, indicates the client should execute this sampling request as a long-running task and return a CreateTaskResult instead of the immediate CreateMessageResult. The actual result can be retrieved later via tasks/result.

_meta: Option<Value>

Optional metadata per MCP 2025-11-25 specification

Trait Implementations

impl Clone for CreateMessageRequest

fn clone(&self) -> CreateMessageRequest

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for CreateMessageRequest

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for CreateMessageRequest

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for CreateMessageRequest

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.