Struct ToolAnnotations 

pub struct ToolAnnotations {
    pub title: Option<String>,
    pub read_only_hint: Option<bool>,
    pub destructive_hint: Option<bool>,
    pub idempotent_hint: Option<bool>,
    pub open_world_hint: Option<bool>,
}

Tool-specific annotations (2025-11-25 Schema Compliance)

NOTE: all properties in ToolAnnotations are hints. They are not guaranteed to provide a faithful description of tool behavior (including descriptive properties like title).

Clients should never make tool use decisions based on ToolAnnotations received from untrusted servers.

Fields

title: Option<String>

A human-readable title for the tool

read_only_hint: Option<bool>

If true, the tool does not modify its environment Default: false

destructive_hint: Option<bool>

If true, the tool may perform destructive updates to its environment If false, the tool performs only additive updates (This property is meaningful only when readOnlyHint == false) Default: true

idempotent_hint: Option<bool>

If true, calling the tool repeatedly with the same arguments will have no additional effect on its environment (This property is meaningful only when readOnlyHint == false) Default: false

open_world_hint: Option<bool>

If true, this tool may interact with an “open world” of external entities If false, the tool’s domain of interaction is closed For example, the world of a web search tool is open, whereas that of a memory tool is not Default: true

Implementations

impl ToolAnnotations

pub fn new() -> Self

Create new empty tool annotations

pub fn with_title<S: Into<String>>(self, title: S) -> Self

Set the human-readable title for the tool

pub fn read_only(self) -> Self

Mark tool as read-only (does not modify environment)

pub fn destructive(self) -> Self

Mark tool as destructive (may perform destructive updates)

pub fn idempotent(self) -> Self

Mark tool as idempotent (same input produces same result)

pub fn open_world(self) -> Self

Mark tool as interacting with open world of external entities

pub fn closed_world(self) -> Self

Mark tool as interacting with closed world (limited domain)

impl ToolAnnotations

pub fn from_improved_metadata( metadata: &ImprovedToolMetadata, title_override: Option<String>, ) -> Self

Create ToolAnnotations from improved metadata with explicit title override

pub fn from_behavior_hints(hints: &ToolBehaviorHints) -> Self

Create minimal ToolAnnotations from behavior hints

Trait Implementations

impl Clone for ToolAnnotations

fn clone(&self) -> ToolAnnotations

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ToolAnnotations

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

Formats the value using the given formatter.

impl Default for ToolAnnotations

fn default() -> ToolAnnotations

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for ToolAnnotations

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl From<&ImprovedToolMetadata> for ToolAnnotations

fn from(metadata: &ImprovedToolMetadata) -> Self

Converts to this type from the input type.

impl From<&ToolBehaviorHints> for ToolAnnotations

fn from(hints: &ToolBehaviorHints) -> Self

Converts to this type from the input type.

impl PartialEq for ToolAnnotations

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

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 ToolAnnotations