When parent_agent.enabled_toolsets is None (the default, meaning all tools
are enabled), subagents incorrectly fell back to DEFAULT_TOOLSETS
(['terminal', 'file', 'web']) instead of inheriting the parent's full
toolset.
Root cause:
- Line 188 used 'or' fallback: None or DEFAULT_TOOLSETS evaluates to
DEFAULT_TOOLSETS
- Line 192 checked truthiness: None is falsy, falling through to else
Fix:
- Use 'is not None' checks instead of truthiness
- When enabled_toolsets is None, derive effective toolsets from
parent_agent.valid_tool_names via the tool registry
Fixes the bug introduced in f75b1d21b and repeated in e5d14445e (PR #3269).
ad567c9a8f