Summary

• pass live agent context through the agent loop to plugin-provided tools
• keep built-in tool behavior unchanged by only exposing agent to plugin tool names
• add tests proving plugin handlers can receive and use live runtime context

Why

Maintainers requested a plugin-first path for the reasoning effort feature. Plugin tool handlers currently cannot access the live AIAgent, which blocks plugin-owned session-state mutations like updating agent.reasoning_config.

This PR adds a small generic seam so plugin tools can receive:

• agent
• task_id
• session_id
• tool_call_id

That enables richer plugin behaviors without hardcoding feature logic into core.

Implementation notes

• model_tools.handle_function_call(...) now accepts optional agent
• run_agent.py passes agent=self from the live agent loop
• only plugin-provided tools receive the live agent kwarg
• PluginContext.register_tool(...) docs now mention runtime kwargs

Test plan

uv run --with pyyaml --with pytest --with pytest-asyncio python -m pytest -o addopts='' tests/hermes_cli/test_plugins.py tests/run_agent/test_run_agent.py -q

Passed locally:

• 270 passed

Closes #7344