video-agent-kit (0.4.3): hooks invoke python3, which doesn't exist on Windows — SessionStart/UserPromptSubmit/Stop hooks fail on every trigger

Environment

• OS: Windows 11 (build 10.0.26200)
• ZCode: desktop client
• Plugin: video-agent-kit 0.4.3
• Python: 3.14 (python.org install — exposes python.exe and the py launcher; there is no python3 on PATH)

Symptom

Every SessionStart, UserPromptSubmit, and Stop event logs a hook failure (hook.run.failed in the ZCode log, source plugin.video-agent-kit@zcode-plugins-official.*, ~50 ms duration = command-not-found). Across one day of normal use this produced ~75 failure entries across all open sessions.

Root cause

hooks/hooks.json invokes all three hook scripts through python3:

• env_check.py (SessionStart)
• check_video_input.py (UserPromptSubmit)
• check_closeout.py (Stop)

Windows Python installers do not create a python3 executable, so the command never resolves.

Suggested fix

Any of:

1. Invoke the scripts with python (present on Windows and nearly all dev machines), or
2. Resolve the interpreter dynamically at hook time (prefer python3, fall back to python/py), or
3. Document a python3-on-PATH requirement for Windows users.

Side note: env_doctor.py correctly pins the MCP SDK to >=1.0.0,<2.0.0 — installing MCP SDK 2.x satisfies import mcp but breaks the 1.x Server API the plugin uses, so that version-pinned check is doing real work.

Local workaround (for anyone hitting this)

Patch the three interpreter refs in the plugin's hooks/hooks.json from python3 to python, and/or drop a python3.cmd shim (@python %*) into a PATH directory that Windows processes can see (e.g. the Python install dir). Both verified working on 0.4.3.

Start with hooks/hooks.json and inspect the commands for env_check.py, check_video_input.py, and check_closeout.py. Reproduce the hook invocations on Windows with the available Python launchers, then verify that SessionStart, UserPromptSubmit, and Stop no longer produce command-not-found failures.