wehub-resource-sync
3.2 KiB
Session model override
The in-chat (bottom) model picker selects a model for the current conversation only — it never rewrites config.yaml, so the Settings global default is preserved (#688), and carries the full model identity so cross-provider switches route correctly.
The override is held in renderer state on each <Chat> run (src/renderer/src/screens/Chat/Chat.tsx), persisted by session id, and sent with every message; it is cleared when the conversation is cleared/reset and is absent on a fresh chat, so new conversations start on the global default. This is distinct from the persisted model-context default that non-chat surfaces read.
Full identity, not just the model name
The override is a SessionModelOverride ({provider, model, baseUrl}), not a bare model string — because switching across providers must change routing, not only the model field.
The picker builds it via src/renderer/src/screens/Chat/hooks/useModelConfig.ts#effectiveOverrideBaseUrl, the same baseUrl rule selectModel applies (keep the URL only for custom/ollama-cloud; clear it for named providers that have a canonical base URL), so the session pick and a persisted save can't drift. It is threaded renderer → preload IPC → main sendMessage as modelOverride.
Desktop-only persistence
The selected model/provider is saved in a desktop-owned table keyed by session id, without storing API keys.
src/main/session-model-override-store.ts holds desktop_session_model_overrides with provider, model, and base_url only. src/renderer/src/screens/Chat/Chat.tsx#Chat restores the saved value for a resumed session, applies it to the local picker with persist:false, and saves later changes once a gateway session id exists. Deleting a session removes the row through src/main/sessions.ts#deleteSessionRows.
Text-only legacy fallback routes via CLI
Text-only legacy turns can use the CLI fallback when a session override changes provider or base URL away from config.yaml.
The upstream desktop model applies the session switch on the active gateway session with /model <model> --provider <provider>, then attaches media and submits on that same session. Hermes Desktop's dashboard transport follows that path; src/main/hermes.ts#shouldForceCliForSessionOverride keeps the CLI escape hatch only for text-only legacy fallback, where it can pass -m <model> and --provider without dropping attachments. Same-provider model swaps stay on the gateway/API path, where the new model string is sufficient. Remote (SSH) mode has no local CLI transport, so it remains limited to the model string.
Attachment turns stay on session transport
Attachment turns must not be forced through the CLI override fallback because the CLI path cannot carry multimodal input.
src/main/hermes.ts#sendMessageViaCli can inline text-file attachments but ignores images, while the gateway/API path preserves image parts and path refs through src/main/hermes.ts#buildUserContent. When a session override is active and the user sends attachments, src/main/hermes.ts#shouldForceCliForSessionOverride leaves the turn eligible for the dashboard/gateway or API transport instead of silently dropping media.