Struct ToolAnnotations 

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

MCP tool annotations per MCP 2025-11-25 spec.

Hints about tool behavior — not security guarantees.

Fields

read_only_hint: Option<bool>

If true, the tool does not modify any state.

destructive_hint: Option<bool>

If true, the tool may perform destructive / irreversible operations.

idempotent_hint: Option<bool>

If true, calling the tool multiple times with the same arguments produces the same result as calling it once.

open_world_hint: Option<bool>

If true, the tool may interact with an unbounded set of external entities (e.g., the filesystem, network).

Implementations

impl ToolAnnotations

pub const fn read_only() -> Self

Read-only tool — does not modify state.

pub const fn destructive() -> Self

Destructive tool — may perform irreversible operations.

pub const fn idempotent() -> Self

Idempotent tool — safe to call multiple times with the same args.

pub const fn mutating() -> Self

Plain mutating tool — creates or updates state but not destructive.

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 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.