Extend the existing on_progress callback to carry structured tool-event
payloads alongside the plain-text hint, so channels can render rich
tool execution state (start/finish/error, arguments, results, file
attachments) rather than only the pre-formatted hint string.
Changes
-------
- AgentLoop._tool_event_start_payload() — builds a version-1 start
payload from a ToolCallRequest
- AgentLoop._tool_event_result_extras() — extracts files/embeds from a
tool result dict
- AgentLoop._tool_event_finish_payloads() — maps tool_calls +
tool_results + tool_events from AgentHookContext into finish payloads
- _LoopHook.before_execute_tools() — passes tool_events=[...] to
on_progress together with the existing tool_hint flag
- _LoopHook.after_iteration() — emits a second on_progress call with
the finish payloads once tool results are available
- _bus_progress() — forwards tool_events as _tool_events in OutboundMessage
metadata so channel implementations can read them
- on_progress type widened to Callable[..., Awaitable[None]] on all
public entry points; _cli_progress updated to accept and ignore
tool_events
The contract is additive: callers that only accept (content, *, tool_hint)
continue to work unchanged. Callers that also accept tool_events receive
the structured data.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
