Struct ToolDefinition 

pub struct ToolDefinition {
    pub name: String,
    pub description: Option<String>,
    pub input_schema: Option<Value>,
    pub title: Option<String>,
}

A tool that the LLM may invoke, expressed as a name + JSON Schema.

This is the agent domain’s own type. Adapter layers are responsible for converting their internal tool representations:

• MCP adapter: McpTool → ToolDefinition
• Built-in tools: constructed directly

The agent domain must not reference McpTool or any crate-external tool type directly.

Fields

name: String

Unique function name exposed to the LLM (e.g. "filesystem_read_file").

description: Option<String>

Human-readable description sent to the LLM to explain when to use the tool.

input_schema: Option<Value>

JSON Schema object describing the tool’s input parameters.

title: Option<String>

Human-readable display title from MCP annotations.title.

When present, surfaces prefer this over the heuristic format_tool_display_name(). Not serialized to the LLM.

Implementations

impl ToolDefinition

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

Create a minimal tool definition with only a name.

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

Attach a human-readable description.

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

Attach a JSON Schema for the tool’s input parameters.

Trait Implementations

impl Clone for ToolDefinition

fn clone(&self) -> ToolDefinition

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ToolDefinition

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for ToolDefinition

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for ToolDefinition

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

where __S: Serializer,

Serialize this value into the given Serde serializer.