Struct Tool 

pub struct Tool { /* private fields */ }

Ad-hoc tool defined inline with a closure handler.

Chain builder methods to configure, then hand the tool to an agent:

let greet = Tool::new("greet", "Say hello")
    .schema(serde_json::json!({"type": "object", "properties": {}}))
    .handler(|_input, _ctx| async {
        Ok(ToolResult::success("hi"))
    });

A handler is required — omitting Tool::handler causes the first invocation to panic. For tools with complex state, implement ToolLike directly on your own type instead.

Implementations

impl Tool

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

A new tool with an empty-object input schema and no handler. Set the handler with Tool::handler before handing the tool to an agent.

pub fn from_tool_file(json: &str) -> Self

Construct a Tool from a .tool.json definition. The returned tool has its name, rendered description, input schema, and read-only flag populated from the JSON; attach a handler via Tool::handler before registering it with an agent. Panics on malformed JSON.

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

Replace the input schema (JSON Schema). Defaults to an empty-object schema.

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

Mark the tool read-only so the loop runs it concurrently with other read-only calls in the same step.

pub fn defer(self, defer: bool) -> Self

Hide the tool’s full definition until it is discovered via ToolSearchTool.

pub fn handler<F, Fut>(self, f: F) -> Self

where F: Fn(Value, ToolContext) -> Fut + Send + Sync + 'static, Fut: Future<Output = ProviderResult<ToolResult>> + Send + 'static,

Install the closure that runs when the model calls this tool. The closure may be a bare async block — the builder boxes the returned future internally. Required: omitting this causes the first invocation to panic.

Trait Implementations

impl ToolLike for Tool

fn name(&self) -> &str

Unique name the model uses to call the tool.

fn description(&self) -> &str

Human-readable description shown to the model.

fn input_schema(&self) -> Value

JSON Schema describing the tool’s arguments.

fn is_read_only(&self) -> bool

Whether this tool has no side effects. Read-only tools in the same step run concurrently; non-read-only tools run serially. Default: false.

fn should_defer(&self) -> bool

Whether the tool’s full definition is hidden until it is discovered via ToolSearchTool. Deferred tools appear to the model as name-only stubs. Default: false.

fn call<'a>( &'a self, input: Value, ctx: &'a ToolContext, ) -> Pin<Box<dyn Future<Output = ProviderResult<ToolResult>> + Send + 'a>>

Run the tool. The future is held by the agent loop and dropped on cancellation; pair long-running work with ToolContext::wait_for_cancel in a tokio::select! to drop the losing branch promptly.