Struct ToolChoice 

pub struct ToolChoice {
    pub mode: Option<ToolChoiceMode>,
}

Controls tool selection behavior for sampling requests (MCP 2025-11-25 draft, SEP-1577)

Fields

mode: Option<ToolChoiceMode>

Controls the tool use ability of the model

• “auto”: Model decides whether to use tools (default)
• “required”: Model MUST use at least one tool before completing
• “none”: Model MUST NOT use any tools

Implementations

impl ToolChoice

pub fn auto() -> Self

Create a new ToolChoice with auto mode

pub fn required() -> Self

Create a new ToolChoice requiring tool use

pub fn none() -> Self

Create a new ToolChoice forbidding tool use

Trait Implementations

impl Clone for ToolChoice

fn clone(&self) -> ToolChoice

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ToolChoice

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

Formats the value using the given formatter.

impl Default for ToolChoice

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for ToolChoice

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for ToolChoice

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

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 ToolChoice

impl StructuralPartialEq for ToolChoice