The gpt-5-mini calls were Lobe's System Agent -- a background model,
separate from the chat model, used for auto-naming conversations, history
summarization, translation, query rewrite, thread naming, and assistant
metadata. Its default is openai/gpt-5-mini, which our OpenAI provider (the
gateway) forwards verbatim; the scoped key blocks it, so every background
task 403'd and the log filled with 'Tried to access gpt-5-mini' while
auto-naming silently failed.
Set SYSTEM_AGENT to route all six documented keys (topic, translation,
agentMeta, queryRewrite, historyCompress, thread) at fleet models --
summarizer for the naming/summarize tasks (same seat as gen at temp 0),
gen where quality matters. Any key left unset falls back to the gpt-5-mini
default, so all six are explicit.
Notably this one IS env-configurable (SYSTEM_AGENT), unlike the per-model
output-token cap which is UI-only -- a mixed result on the
manageable-by-agent axis.
Replacement candidate for the hand-rolled gateway-chat HTML surface, which
the operator does not want to keep improving -- it has already produced two
defects tonight.
Chosen over Open WebUI on weight, measured from the registries rather than
recalled: Lobe 143 MB compressed / 1 layer vs Open WebUI 1,825 MB / 19
layers, a 12.8x difference. Open WebUI was declined in June 2026 on weight
and that still holds; its secondary recorded objection (empty-tools 400
against vLLM) is now moot since strip_empty_tools covers the normal API
path and only missed LiteLLM's built-in playground.
CREDENTIAL POSTURE: deliberately NOT the shared all-agents key, which
reaches the paid GLM/Kimi passthroughs -- a LAN-exposed chat UI holding it
would let anyone reaching the port spend vendor credits from a pool shared
across every project. Minted a scoped LiteLLM virtual key
(key_alias lobe-chat-esh) limited to the 20 free local models, and verified
the scoping BOTH ways: gen answers, glm-5.2 / kimi-k3 / gen-frontier all
return 'key not allowed to access model'. Secrets vaulted, host .env 0600.
Verified from INSIDE the container, not just from the host: /v1/models
returns the fleet seats and a gen round-trip returns 'ok', so the app's own
network path and key both work. Container healthy, / -> 307 -> /chat -> 200.
Documents the open question this deploy exists to answer: whether Lobe's
TTS is ENV-configurable or UI-only. That is the operator's deciding
criterion and is NOT yet established -- Open WebUI has dedicated AUDIO_TTS_*
vars, Lobe documents a shared OPENAI_PROXY_URL which should carry TTS since
LiteLLM serves audio/speech on the same base, but that is inference.
Also records the ext-tts voice foot-gun: unknown voices 404 and can trip
the router cooldown, so the voice must be pinned rather than left at a UI
default.
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