What does this PR do?

Symptom

• WeChat image/file delivery via the send_message tool fails consistently with:
  RuntimeError: Timeout context manager should be used inside a task
• The error occurs because aiohttp.TimerContext.current_task() returns None when the session was created on a different event loop than the one calling session.post().
• Text-only messages sent through the gateway's native adapter path were unaffected (they run inside the gateway's own event loop).

Root Cause

• v2026.4.23 introduced a "lazy recreate session" optimization in send_weixin_direct().
• The optimization reused the gateway's long-lived aiohttp.ClientSession (from _LIVE_ADAPTERS) for one-shot sends triggered by the send_message tool.
• These tool calls execute inside a ThreadPoolExecutor worker thread via _run_async().
• The gateway's ClientSession was created on the gateway's event loop, but session.post(timeout=...) was called from the worker thread — a cross-event-loop access that aiohttp.TimerContext does not support.
• TimerContext.__enter__() calls asyncio.current_task(loop=session._loop). Since no task is running on the gateway's loop inside the worker thread, it returns None, raising the RuntimeError.

Intent of the Original Change

• Avoid re-creating TCP/SSL connections (handshake overhead) on every send_message tool invocation.
• Reduce latency for repeated WeChat sends (text + image uploads make 3-4 API calls per message).

Risks of the Original Approach

• Thread-safety violation: aiohttp.ClientSession is explicitly documented as not thread-safe.
• SSL connection corruption: Concurrent writes to the same TCP connector socket can cause response cross-talk between worker threads.
• Cookie/token state pollution: Session-level state can leak between concurrent sends for different users.
• Authentication boundary break: Shared session flattens the isolation between different chat contexts.

Type of Change

• 🐛 Bug fix (non-breaking change that fixes an issue)
• ✨ New feature (non-breaking change that adds functionality)
• 🔒 Security fix
• 📝 Documentation update
• ✅ Tests (adding or improving test coverage)
• ♻️ Refactor (no behavior change)
• 🎯 New skill (bundled or hub)

Changes Made

Fix

1. Added _get_worker_session() to model_tools.py:

   • Each worker thread maintains its own persistent aiohttp.ClientSession via threading.local().
   • The session is bound to the thread's persistent event loop (_get_worker_loop()), so TimerContext.current_task() always finds a valid task.
   • Sessions are lazily created on first use and reused across subsequent calls within the same thread.
   • SSL connector setup mirrors _make_ssl_connector() from gateway/platforms/weixin.py.

2. Removed lazy recreate branch from send_weixin_direct():

   • Deleted the _LIVE_ADAPTERS.get(resolved_token) shortcut (26 lines).
   • Replaced async with aiohttp.ClientSession(trust_env=True, connector=...) with session = _get_worker_session().
   • The adapter is still created fresh per call (adapter lifecycle unchanged).
   • Function reduced from 98 to 72 lines.

Behavior After Fix

• Worker threads send WeChat messages through their own session, bound to their own event loop.
• TCP/SSL connections are still reused within each thread — no per-call handshake penalty.
• No cross-event-loop access: TimerContext.current_task() always returns the running task on the worker's loop.
• The gateway's own adapter sending path is unchanged — it still uses its original session on the gateway loop.

Conflict Resolution

During review, a parallel approach was identified: replacing ClientTimeout with asyncio.wait_for() (chenlinfeng, May 3). This masks the TimerContext error but leaves the underlying ClientSession thread-safety violations intact.

The thread-local session approach eliminates all root-cause risks simultaneously. asyncio.wait_for() only replaces the error type (TimeoutError vs RuntimeError) without fixing the architectural problem.

Files Changed

• model_tools.py (+13 lines): Added _get_worker_session() with thread-local persistent session management.
• gateway/platforms/weixin.py (-21 lines): Removed lazy recreate block; replaced async with ClientSession with persistent worker session getter.

How to Test

Verification

• send_message tool with WeChat image attachments: ✅ success: true, valid message_id returned.
• Gateway logs: No RuntimeError or send failed entries post-fix.
• Thread isolation confirmed: Different worker threads get different sessions; same thread reuses the same session.

Checklist

Code

• I've read the Contributing Guide
• My commit messages follow Conventional Commits (fix(scope):, feat(scope):, etc.)
• I searched for existing PRs to make sure this isn't a duplicate
• My PR contains only changes related to this fix/feature (no unrelated commits)
• I've run pytest tests/ -q and all tests pass
• I've added tests for my changes (required for bug fixes, strongly encouraged for features)
• I've tested on my platform:

Documentation & Housekeeping

• I've updated relevant documentation (README, docs/, docstrings) — or N/A
• I've updated cli-config.yaml.example if I added/changed config keys — or N/A
• I've updated CONTRIBUTING.md or AGENTS.md if I changed architecture or workflows — or N/A
• I've considered cross-platform impact (Windows, macOS) per the compatibility guide — or N/A
• I've updated tool descriptions/schemas if I changed tool behavior — or N/A

For New Skills

• This skill is broadly useful to most users (if bundled) — see Contributing Guide
• SKILL.md follows the standard format (frontmatter, trigger conditions, steps, pitfalls)
• No external dependencies that aren't already available (prefer stdlib, curl, existing Hermes tools)
• I've tested the skill end-to-end: hermes --toolsets skills -q "Use the X skill to do Y"

Screenshots / Logs