Shawn Jasper 55474011c9
fix(subagent): inherit parent agent's tool_groups in task_tool (#2305)
* fix(subagent): inherit parent agent's tool_groups in task_tool

When a custom agent defines tool_groups (e.g. [file:read, file:write, bash]),
the restriction is correctly applied to the lead agent. However, when the lead
agent delegates work to a subagent via the task tool, get_available_tools() is
called without the groups parameter, causing the subagent to receive ALL tools
(including web_search, web_fetch, image_search, etc.) regardless of the parent
agent's configuration.

This fix propagates tool_groups through run metadata so that task_tool passes
the same group filter when building the subagent's tool set.

Changes:
- agent.py: include tool_groups in run metadata
- task_tool.py: read tool_groups from metadata and pass to get_available_tools()

* fix: initialize metadata before conditional block and update tests for tool_groups propagation

- Initialize metadata = {} before the 'if runtime is not None' block to
  avoid Ruff F821 (possibly-undefined variable) and simplify the
  parent_tool_groups expression.
- Update existing test assertion to expect groups=None in
  get_available_tools call signature.
- Add 3 new test cases:
  - test_task_tool_propagates_tool_groups_to_subagent
  - test_task_tool_no_tool_groups_passes_none
  - test_task_tool_runtime_none_passes_groups_none
2026-04-18 22:17:37 +08:00
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