- Introduce a DEFAULT_RUNNER global and a set_default_runner() function to allow callers to specify a default Runner for agent runs.- Update Runner.run, run_sync, and run_streaming to use DEFAULT_RUNNER if set, otherwise fallback to DefaultRunner.- Add detailed docstrings to run, run_sync, and run_streaming methods for clarity on agent execution flow and exceptions.

This commit renames the abstract and concrete methods run_impl, run_sync_impl, and run_streamed_impl in the Runner and DefaultRunner classes to _run_impl, _run_sync_impl, and _run_streamed_impl (or _start_streaming as appropriate) for improved naming consistency. Updates all method calls and test mocks accordingly. No behavior changes.

…lace global with accessor- Move TraceProvider and related logic from setup.py to new provider.py module- Replace direct GLOBAL_TRACE_PROVIDER references with get_trace_provider() accessor throughout tracing code- Update init and util imports to use get_trace_provider- Call set_trace_provider(TraceProvider()) on init- Remove ID and time generation logic from util, delegate to TraceProvider- Update SpanImpl to always use passed-in span_id

…tructor

…mplementation- Add abstract TraceProvider base class to define tracing API- Move default tracing logic to DefaultTraceProvider- Update __init__.py to export both TraceProvider and DefaultTraceProvider, and use DefaultTraceProvider as default- Aligns span/trace management and enables alternative provider implementations

# Conflicts:#src/agents/__init__.py#src/agents/run.py

…via cls

…itialized- Add get_default_runner to retrieve current default runner.- Always assign DEFAULT_RUNNER to a DefaultRunner at module init.- Replace fallback logic (`DEFAULT_RUNNER or DefaultRunner()`) with direct use of initialized DEFAULT_RUNNER.- Update __all__ in __init__.py to export get_default_runner.- Minor update to tracing/__init__.py __all__ for consistency.

…ls, _get_model) from DefaultRunner to Runner base class

## Summary- rename DefaultRunner to DefaultAgentRunner and extend new AgentRunnerbase- remove `set_default_runner`/`get_default_runner` helpers- rename abstract methods on AgentRunner (no underscore)- update tests and imports for new API## Testing- `make format`- `make lint`- `make mypy`- `make tests`------https://chatgpt.com/codex/tasks/task_i_6851851acce8832099adc70d8197016c

…imports and __all__ entries

…rder in voice workflow tests

# Conflicts:#src/agents/run.py

…reorder imports

…UNNER to new AgentRunner if passed Noneconftest.py: add autouse fixture to clear DEFAULT_AGENT_RUNNER before each test