Struct ToolAnnotations 

pub struct ToolAnnotations {
    pub destructive: Option<bool>,
    pub idempotent: Option<bool>,
    pub read_only: Option<bool>,
    pub open_world_hint: Option<bool>,
}

Tool annotations for additional metadata.

These annotations provide hints about tool behavior to help clients make informed decisions about tool usage.

Fields

destructive: Option<bool>

Whether the tool may cause destructive side effects. True means the tool modifies external state (e.g., deleting files). Serialized as the MCP-spec destructiveHint field.

idempotent: Option<bool>

Whether the tool is idempotent (safe to retry without side effects). True means calling the tool multiple times has the same effect as calling it once. Serialized as the MCP-spec idempotentHint field.

read_only: Option<bool>

Whether the tool is read-only (has no side effects). True means the tool only reads data without modifying anything. Serialized as the MCP-spec readOnlyHint field.

open_world_hint: Option<bool>

Whether the tool interacts with an “open world” of external entities. Per the MCP spec openWorldHint is a boolean: true if the tool may reach external/unknown systems, false if it operates over a closed/local domain.

Implementations

impl ToolAnnotations

pub fn new() -> Self

Creates a new empty annotations struct.

pub fn destructive(self, value: bool) -> Self

Sets the destructive annotation.

pub fn idempotent(self, value: bool) -> Self

Sets the idempotent annotation.

pub fn read_only(self, value: bool) -> Self

Sets the read_only annotation.

pub fn open_world_hint(self, value: bool) -> Self

Sets the open_world_hint annotation.

Per the MCP spec openWorldHint is a boolean: true if the tool interacts with an open world of external entities, false for a closed/local domain.

pub fn is_empty(&self) -> bool

Returns true if any annotation is set.

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 Eq for ToolAnnotations

impl PartialEq for ToolAnnotations

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

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

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