Rebased onto current main, where the OpenRouter tool-use 404 is now
handled natively (the bundled demo's exact reason to exist), so the demo
plugin is removed per the standalone-repo policy and every test now uses
a synthetic unclaimed error (fake provider, neutral message, no status
code) that no present or future built-in rule can claim.
classify_api_error is now explicitly Python-plugin-only: VALID_HOOKS
doubles as the shell-hook allow-list, but the shell response parser has
no channel for the classification directive, so shell registrations are
refused at config parse with a warning instead of being silently
ignored (new SHELL_UNSUPPORTED_HOOKS set + regression test).
The hook is documented in the hooks reference as the third
behavior-changing hook, with the full kwargs contract, return shape,
and the Python-only note.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PnMCvi2vXqfs996AjVeF2F
0180907fe8