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Tool

adk_tool

Trait Tool 

Source 
pub trait Tool: Send + Sync {
    // Required methods
    fn name(&self) -> &str;
    fn description(&self) -> &str;
    fn execute<'life0, 'async_trait>(
        &'life0 self,
        ctx: Arc<dyn ToolContext>,
        args: Value,
    ) -> Pin<Box<dyn Future<Output = Result<Value, AdkError>> + Send + 'async_trait>>
       where 'life0: 'async_trait,
             Self: 'async_trait;

    // Provided methods
    fn declaration(&self) -> Value { ... }
    fn enhanced_description(&self) -> String { ... }
    fn is_long_running(&self) -> bool { ... }
    fn is_builtin(&self) -> bool { ... }
    fn parameters_schema(&self) -> Option<Value> { ... }
    fn response_schema(&self) -> Option<Value> { ... }
    fn required_scopes(&self) -> &[&str] { ... }
    fn is_read_only(&self) -> bool { ... }
    fn is_concurrency_safe(&self) -> bool { ... }
}
Expand description

The core trait for all tools that agents can invoke.

Tools extend agent capabilities with custom functions. Each tool has a name, description, optional parameter schema, and an async execute method.

Required Methods§

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fn name(&self) -> &str

Returns the unique name of this tool.

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fn description(&self) -> &str

Returns a human-readable description of what this tool does.

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fn execute<'life0, 'async_trait>( &'life0 self, ctx: Arc<dyn ToolContext>, args: Value, ) -> Pin<Box<dyn Future<Output = Result<Value, AdkError>> + Send + 'async_trait>>
where 'life0: 'async_trait, Self: 'async_trait,

Executes the tool with the given context and arguments.

Provided Methods§

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fn declaration(&self) -> Value

Returns the tool declaration that should be exposed to model providers.

The default implementation produces the standard ADK function-tool declaration (name, description, optional parameters, optional response). Provider-specific built-in tools may override this to attach additional metadata that the provider adapters understand.

§Example
ⓘ
fn declaration(&self) -> serde_json::Value {
    serde_json::json!({
        "name": self.name(),
        "description": self.description(),
        "x-adk-openai-tool": {
            "type": "web_search_2025_08_26"
        }
    })
}
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fn enhanced_description(&self) -> String

Returns an enhanced description that may include additional notes. For long-running tools, this includes a warning not to call the tool again if it has already returned a pending status. Default implementation returns the base description.

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fn is_long_running(&self) -> bool

Indicates whether the tool is a long-running operation. Long-running tools typically return a task ID immediately and complete the operation asynchronously.

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fn is_builtin(&self) -> bool

Indicates whether this tool is a built-in server-side tool (e.g., google_search, url_context).

Built-in tools are executed server-side by the model provider and should not be executed locally by the agent. The default implementation returns false.

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fn parameters_schema(&self) -> Option<Value>

Returns the JSON Schema for this tool’s parameters, if any.

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fn response_schema(&self) -> Option<Value>

Returns the JSON Schema for this tool’s response, if any.

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fn required_scopes(&self) -> &[&str]

Returns the scopes required to execute this tool.

When non-empty, the framework can enforce that the calling user possesses all listed scopes before dispatching execute(). The default implementation returns an empty slice (no scopes required).

§Example
ⓘ
fn required_scopes(&self) -> &[&str] {
    &["finance:write", "verified"]
}
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fn is_read_only(&self) -> bool

Indicates whether this tool performs no side effects. Read-only tools may be executed concurrently in Auto mode.

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fn is_concurrency_safe(&self) -> bool

Indicates whether this tool is safe for concurrent execution. Used by the Parallel strategy to validate dispatch safety.

Dyn Compatibility§

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors§