When pydantic-ai-slim is installed at a version < 1.73 but the Hooks class can be imported, setup_once() calls _patch_graph_nodes() and returns without registering hooks — but are_request_hooks_available remains True. This causes agent_run.py wrappers (lines 112, 161) to inject {"_sentry_span": None} into every agent run's metadata even though no hook will ever populate that span. Consider setting PydanticAIIntegration.are_request_hooks_available = False before returning in the version-check branch.

Also found at:

• sentry_sdk/integrations/pydantic_ai/__init__.py:183-184

When pydantic-ai-slim version is >= 1.73 but Hooks fails to import, the function returns silently without calling _patch_graph_nodes(), so model request spans are never captured. Before this change, Hooks is None always fell back to _patch_graph_nodes().