The condition if not metadata: at lines 115 and 164 uses a falsy check, while the analogous check in patched_init at line 106 uses if metadata is None:. If a user explicitly passes metadata={} to Agent.run() or Agent.run_stream(), the empty dict will be replaced with {"_sentry_span": None} rather than having the key added to the user's dict. This inconsistency could break code that holds a reference to the original empty dict expecting it to be mutated.