[VitorCoelho]

What

HighLevelActionSet.to_tool_description() now reads each action's signature from the function registered in the action set, instead of globals()[tool_name] in highlevel.py.

Why

globals() of the highlevel module only contains the built-in actions, so:

• an action set built with custom_actions raised KeyError on the first custom action, so tool-use agents could not describe custom actions at all;
• a custom action that reuses a built-in name (e.g. its own click(bid, note)) was silently described with the built-in click(bid, button, modifiers) signature.

def my_action(bid: str, times: int = 2):
    """
    Clicks an element several times.

    Examples:
        my_action('a51', 3)
    """

HighLevelActionSet(subsets=["custom"], custom_actions=[my_action]).to_tool_description()
# main: KeyError: 'my_action'

The functions are kept in a private _action_functions dict filled in __init__, next to action_set. to_python_code() and the rest of the public API are unchanged.

How it was tested

• New test_tool_description_custom_actions in tests/core/test_actions_highlevel.py (no browser needed): checks the schema of a custom action and of a custom action named click, for both the openai and anthropic formats. It fails on main with KeyError and passes with the fix.
• pytest -n 5 -m 'not pricy' tests/core (headless Chromium, Playwright 1.56 instead of the pinned 1.44): everything passes except test_task.py::test_mock_image_goal_task (needs internet access, which my environment does not have) and test_observation.py::test_axtree_to_text; both fail the same way on main here, so they are unrelated to this change.
• black 24.2.0 (repo config) is clean.