fix(model-switch): resolve bare model names via custom_providers catalog

[rzbdz]

Problem

When a user types /model claude-sonnet-4.6 while on a custom provider (e.g. smt-claude), the switch fails with:

✗ Note: `claude-sonnet-4.6` was not found in this custom endpoint's model listing (https://openrouter.ai/api/v1/models).
  Similar models: `anthropic/claude-sonnet-4.6`, ...

Three root causes:

1. cli.py: _handle_model_switch only loaded custom_providers in the no-args picker path. When a model name was given, switch_model was called with custom_providers=None.

2. model_switch.py: No step searched the user's custom_providers models catalog before falling through to a live API probe, which could hit the wrong URL.

3. model_switch.py / models.py: custom:smt-claude slugs weren't recognized as custom in the is_custom guard or in validate_requested_model.

Fix

• New _find_model_in_custom_providers() helper scans every custom_providers entry's models dict/list. Matching is case-insensitive and normalises dots↔hyphens (claude-sonnet-4.6 matches claude-sonnet-4-6).
• Inserted as step c2 in PATH B of switch_model() — before any live API probe.
• cli.py loads custom_provs unconditionally before calling switch_model().
• is_custom guard extended to cover custom:* slugs.
• validate_requested_model normalises custom:* → "custom".

Tests

5 new tests in tests/hermes_cli/test_model_switch_custom_providers.py. All 2440 existing tests pass.

[alt-glitch]

Note: #13760 was a prior closed attempt at the same fix; this is the replacement PR.

[alt-glitch]

Note: #13760 was a prior closed attempt at the same fix; this is the replacement PR.

[trevorgordon981]

I have tested this solution locally. The model-switch logic now correctly resolves bare model names via the custom_providers catalog. This ensures that users can switch to custom providers using simple model names without needing fully qualified strings. The fix is stable and ready for merge.\n\nTested and confirmed. ✅

[trevorgordon981]

I have tested this solution locally. The model-switch logic now correctly resolves bare model names via the custom_providers catalog. This ensures that users can switch to custom providers using simple model names without needing fully qualified strings. The fix is stable and ready for merge.\n\nTested and confirmed. ✅

[zons-zhaozhy]

This fix covers custom_providers path, but providers: dict has same problem.

Reproduce:

# config.yaml
model:
  default: sensenova-6.7-flash-lite
  provider: sensenova
providers:
  sensenova:
    base_url: https://token.sensenova.cn/v1
    api_key: sk-xxx

Run /model sensenova-6.7-flash-lite under sensenova provider, model name got sensenova/ prefix added, provider silently switched to OpenRouter.

Root cause is same — detect_provider_for_model() matched model in OpenRouter catalog, but is_custom guard not cover non-built-in provider defined in providers: dict.

I did a general check using get_provider(current_provider) is None, both paths covered: zons-zhaozhy@917afabc6

Tests: zons-zhaozhy@c64056e30

[teknium1]

Closing as superseded by #28908.

Triage notes (medium confidence):
Merged PR #28908 'fix(model): match bare custom provider by active base URL' (plus #17891, #18185) added custom_providers resolution before live API probe in hermes_cli/model_switch.py (see custom_providers and isinstance(custom_providers, list) block ~line 948).

Thanks for the contribution — the underlying problem this PR addresses has been resolved by the linked PR on current main. If you believe this was closed in error, please comment and we'll reopen.

(Bulk-closed during a CLI PR triage sweep.)