Struct Tool 

pub struct Tool {
    pub name: String,
    pub title: Option<String>,
    pub description: Option<String>,
    pub input_schema: ToolInputSchema,
    pub output_schema: Option<ToolOutputSchema>,
    pub annotations: Option<ToolAnnotations>,
    pub meta: Option<HashMap<String, Value>>,
}

Represents a tool that can be executed by an MCP server, as per the MCP 2025-06-18 specification.

A Tool definition includes its programmatic name, a human-readable description, and JSON schemas for its inputs and outputs.

Fields

name: String

The programmatic name of the tool, used to identify it in CallToolRequest.

title: Option<String>

An optional, user-friendly title for the tool. Display name precedence is: title, annotations.title, then name.

description: Option<String>

A human-readable description of what the tool does, which can be used by clients or LLMs.

input_schema: ToolInputSchema

The JSON Schema object defining the parameters the tool accepts.

output_schema: Option<ToolOutputSchema>

An optional JSON Schema object defining the structure of the tool’s successful output.

annotations: Option<ToolAnnotations>

Optional, additional metadata providing hints about the tool’s behavior.

meta: Option<HashMap<String, Value>>

A general-purpose metadata field for custom data.

Implementations

impl Tool

pub fn new(name: impl Into<String>) -> Self

Creates a new Tool with a given name.

Panics

Panics if the name is empty or contains only whitespace.

pub fn with_description( name: impl Into<String>, description: impl Into<String>, ) -> Self

Creates a new Tool with a name and a description.

Panics

Panics if the name is empty or contains only whitespace.

pub fn with_input_schema(self, schema: ToolInputSchema) -> Self

Sets the input schema for this tool.

Example

let schema = ToolInputSchema::empty();
let tool = Tool::new("my_tool").with_input_schema(schema);

pub fn with_output_schema(self, schema: ToolOutputSchema) -> Self

Sets the output schema for this tool.

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

Sets the user-friendly title for this tool.

pub fn with_annotations(self, annotations: ToolAnnotations) -> Self

Sets the annotations for this tool.

Trait Implementations

impl Clone for Tool

fn clone(&self) -> Tool

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Tool

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

Formats the value using the given formatter.

impl Default for Tool

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for Tool

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for Tool

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.