Summary

Skip redundant any_to_str() call in _run_sequential_workflow when agent.run() already returns a string (the common path).

Changes

• Added isinstance(current_task, str) guard before any_to_str() call at line 577
• Near-zero cost check that avoids function call overhead on every agent step

Before

current_task = agent.run(task=self.conversation.get_str(), img=img)
current_task = any_to_str(current_task)  # Always called, even when already str

After

current_task = agent.run(task=self.conversation.get_str(), img=img)
if not isinstance(current_task, str):
    current_task = any_to_str(current_task)  # Only when needed

Test plan

• Existing tests pass unchanged (behavior is identical)
• any_to_str() still called for non-string returns (dicts, lists, objects)
• String returns skip the redundant conversion

Fixes #1462

📚 Documentation preview 📚: https://swarms--1492.org.readthedocs.build/en/1492/