Fixes:
- app.js was tracking primaryBackend locally but never included
model: primaryBackend in the /chat POST body, so the server always
used settings.primary_backend regardless of what the user clicked.
Now model: primaryBackend is sent on every chat request.
- Responses were only annotated when fallback occurred. Now every
assistant message shows a small model tag at the bottom right.
chat.py:
- _backend_label() resolves human-readable name:
claude → "Claude", gemini → "Gemini",
local → registry label (e.g. "Gemma 4 E4B") or model_name
- SSE payload now includes backend_label field
app.js:
- model: primaryBackend added to /chat fetch body
- After every response, appends .model-tag div with backend_label
- Fallback shows "⚡ fallback → <label>" in amber; normal is muted
- Removed separate system message for fallback (tag covers it)
style.css:
- .model-tag: small muted text, right-aligned, separated by thin line
- .model-tag.fallback: amber (#f59e0b)
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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