The Copilot API returns HTTP 400 "model_not_supported" when it receives a
model ID it doesn't recognize (vendor-prefixed like
`anthropic/claude-sonnet-4.6` or dash-notation like `claude-sonnet-4-6`).
Two bugs combined to leave both formats unhandled:
1. `_COPILOT_MODEL_ALIASES` in hermes_cli/models.py only covered bare
dot-notation and vendor-prefixed dot-notation. Hermes' default Claude
IDs elsewhere use hyphens (anthropic native format), and users with an
aggregator-style config who switch `model.provider` to `copilot`
inherit `anthropic/claude-X-4.6` — neither case was in the table.
2. The Copilot branch of `normalize_model_for_provider()` only stripped
the vendor prefix when it matched the target provider (`copilot/`) or
was the special-cased `openai/` for openai-codex. Every other vendor
prefix survived to the Copilot request unchanged.
Fix:
- Add dash-notation aliases (`claude-{opus,sonnet,haiku}-4-{5,6}` and the
`anthropic/`-prefixed variants) to the alias table.
- Rewire the Copilot / Copilot-ACP branch of
`normalize_model_for_provider()` to delegate to the existing
`normalize_copilot_model_id()`. That function already does alias
lookups, catalog-aware resolution, and vendor-prefix fallback — it was
being bypassed for the generic normalisation entry point.
Because `switch_model()` already calls `normalize_model_for_provider()`
for every `/model` switch (line 685 in model_switch.py), this single fix
covers the CLI startup path (cli.py), the `/model` slash command path,
and the gateway load-from-config path.
Closes#6879
Credits dsr-restyn (#6743) who independently diagnosed the dash-notation
case; their aliases are folded into this consolidated fix alongside the
vendor-prefix stripping repair.
29d5d36b14