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>,
}

What calling a tool does to the world, as the Model Context Protocol’s tool annotations state it, and spelled as they are on its wire (readOnlyHint, …), so an MCP tool’s annotations read straight into one. Each is a hint a tool’s author gives: a host’s policies read them (approval, plan mode, which calls run side by side), never trusting a tool it does not trust for them. A hint left unset takes the protocol’s default, which the accessors apply: not read-only, destructive, not idempotent, open world.

use rig_core::completion::ToolAnnotations;

let read = ToolAnnotations::default().with_read_only(true).with_open_world(false);
assert!(read.read_only() && !read.destructive() && !read.open_world());
let unknown = ToolAnnotations::default();
assert!(!unknown.read_only() && unknown.destructive() && unknown.open_world());
let mcp: ToolAnnotations = serde_json::from_value(serde_json::json!({"readOnlyHint": true}))?;
assert!(mcp.read_only());

Fields

title: Option<String>

A human-readable title for the tool.

read_only_hint: Option<bool>

Whether the tool changes nothing in its environment.

destructive_hint: Option<bool>

Whether a tool that changes things may also destroy or overwrite what was there (rather than only add). Meaningless for a read-only tool.

idempotent_hint: Option<bool>

Whether calling the tool again with the same arguments has no further effect. Meaningless for a read-only tool.

open_world_hint: Option<bool>

Whether the tool reaches beyond a closed set of things, such as the web or a shell; false for one that works on a known store, such as the project’s files.

Implementations

impl ToolAnnotations

pub fn is_empty(&self) -> bool

Whether nothing is stated.

pub fn read_only(&self) -> bool

Whether the tool changes nothing: the hint, else false.

pub fn destructive(&self) -> bool

Whether the tool may destroy or overwrite something: never for a read-only tool, else the hint, else true.

pub fn idempotent(&self) -> bool

Whether repeating a call has no further effect: always for a read-only tool, else the hint, else false.

pub fn open_world(&self) -> bool

Whether the tool reaches an open world: the hint, else true.

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

The same annotations with a title.

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

The same annotations stating whether the tool is read-only.

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

The same annotations stating whether the tool is destructive.

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

The same annotations stating whether the tool is idempotent.

pub fn with_open_world(self, open_world: bool) -> Self

The same annotations stating whether the tool reaches an open world.

Trait Implementations

impl Clone for ToolAnnotations

fn clone(&self) -> Self

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() -> Self

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 Hash for ToolAnnotations

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for ToolAnnotations

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