工具定义方式

class Tool(metaclass=_ToolMeta):
    """tool class that defined the data types and content for LLM modules"""

    def __init__(self, card: ToolCard):
        ...

    @abstractmethod
    async def invoke(self, inputs: Input, **kwargs) -> Output:
        """Execute the tool with provided inputs and return final result."""

    @abstractmethod
    async def stream(self, inputs: Input, **kwargs) -> AsyncIterator[Output]:
        ...

# _ToolMeta.__call__ 在实例化时把 invoke/stream 包进 _lifecycle_invoke /
# _lifecycle_stream（同文件 76-158 行），生命周期由框架织入而非工具自理。

pub struct ToolRegistry {
    tools: IndexMap<ToolName, RegisteredTool>,
    first_collision: Option<ToolName>,
}

impl ToolRegistry {
    pub(crate) fn from_tools(tools: impl IntoIterator<Item = Arc<dyn CoreToolRuntime>>) -> Self {
        let mut registry = Self::default();

        for runtime in tools {
            registry.register_trusted(runtime);
        }
        ...

export interface ToolDefinition extends ToolSchema {
  /** Mandatory canonical output declaration. */
  readonly output: ToolOutputDefinition
  /**
   * Run one accepted call and return only its canonical lossless-JSON value.
   * Async work must observe or forward exec.signal and settle only after its
   * owned work reaches quiescence. The registry preserves caller cancellation
   * through around-dispatch signal replacement and does not abandon this
   * promise, but it cannot hard-kill same-process code.
   */
  execute(args: unknown, exec: ToolRunContext): Promise<unknown>

const bashSchema = Type.Object({
	command: Type.String({ description: "Bash command to execute" }),
	timeout: Type.Optional(Type.Number({ description: "Timeout in seconds (optional, no default timeout)" })),
});

export type BashToolInput = Static<typeof bashSchema>;

export function createBashTool<TContext extends ExecutionToolContext = ExecutionToolContext>(
	...
)

// harness/tools/index.ts 的全部导出：createBashTool / createReadTool /
// createWriteTool / createEditTool —— 内核工具就这四个。