Struct CreateMessageRequestBuilder 

pub struct CreateMessageRequestBuilder { /* private fields */ }

Builder for CreateMessageRequest.

Implementations

impl CreateMessageRequestBuilder

pub fn model(self, m: impl Into<ModelId>) -> Self

Set the model. Required.

pub fn max_tokens(self, n: u32) -> Self

Set the max output tokens. Required.

pub fn system(self, s: impl Into<SystemPrompt>) -> Self

Set the system prompt.

pub fn messages(self, msgs: Vec<MessageInput>) -> Self

Replace the entire conversation history.

pub fn user(self, content: impl Into<MessageContent>) -> Self

Append a user-authored message to the history.

pub fn assistant(self, content: impl Into<MessageContent>) -> Self

Append an assistant-authored message (typically used for prefill).

pub fn tools(self, tools: Vec<Tool>) -> Self

Set the available tools.

pub fn tool_choice(self, choice: ToolChoice) -> Self

Set the tool-use policy.

pub fn temperature(self, t: f32) -> Self

Set the sampling temperature.

pub fn top_p(self, p: f32) -> Self

Set the nucleus sampling cutoff.

pub fn top_k(self, k: u32) -> Self

Set the top-k sampling cutoff.

pub fn stop_sequences(self, seqs: Vec<String>) -> Self

Set custom stop sequences.

pub fn metadata(self, m: MessageMetadata) -> Self

Set request metadata (currently user_id only).

pub fn service_tier(self, tier: RequestServiceTier) -> Self

Set the request-side service tier.

pub fn thinking(self, t: ThinkingConfig) -> Self

Set the extended-thinking config.

pub fn mcp_servers(self, servers: Vec<McpServerConfig>) -> Self

Set the MCP servers exposed on this request.

pub fn container(self, id: impl Into<String>) -> Self

Set the container ID for the code-execution built-in tool.

pub fn cache_control_on_system(self) -> Self

Sugar: apply an ephemeral cache breakpoint at the end of the system prompt.

• Some(Text(s)) becomes a single text block with cache_control: ephemeral.
• Some(Blocks(_)) has cache_control: ephemeral set on the last text block.
• None is a no-op.

pub fn cache_system(self) -> Self

Shorter alias for Self::cache_control_on_system.

pub fn cache_system_with_ttl(self, ttl: impl Into<String>) -> Self

Like Self::cache_system but with an explicit TTL ("5m", "1h"). The "1h" form requires the extended-cache-ttl-2025-04-11 beta header.

pub fn cache_control_on_last_user(self) -> Self

Sugar: apply an ephemeral cache breakpoint to the last user-authored message in the history.

String content is converted to a single text block carrying cache_control: ephemeral. Block content has cache_control set on the last block that supports it (text, image, document, tool_result). No-op if there are no user-authored messages.

pub fn cache_last_user(self) -> Self

Shorter alias for Self::cache_control_on_last_user.

pub fn cache_last_user_with_ttl(self, ttl: impl Into<String>) -> Self

Like Self::cache_last_user but with an explicit TTL.

pub fn cache_control_on_tools(self) -> Self

Sugar: apply an ephemeral cache breakpoint to the last tool definition. The server caches all tool definitions up to that point; useful when the same tool list is reused across many requests. No-op if no tools are configured.

pub fn cache_tools(self) -> Self

Shorter alias for Self::cache_control_on_tools.

pub fn cache_tools_with_ttl(self, ttl: impl Into<String>) -> Self

Like Self::cache_tools but with an explicit TTL.

pub fn build(self) -> Result<CreateMessageRequest>

Finalize the request.

Errors

Returns Error::InvalidConfig if model or max_tokens was not set.

Trait Implementations

impl Debug for CreateMessageRequestBuilder

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

Formats the value using the given formatter.

impl Default for CreateMessageRequestBuilder

fn default() -> CreateMessageRequestBuilder

Returns the “default value” for a type.