Feature clarification: AI provider enhancements — thinking mode, vision image input, and API host normalization

Background

We run a self-hosted Apache Answer as a community FAQ site, with an OpenAI-compatible LLM gateway (SenseNova). While integrating the AI feature we hit three concrete gaps. Following @LinkinStars's suggestion on #1594, this issue clarifies the proposed feature set before the PR is resubmitted.

Proposed enhancements

1. API host normalization (bugfix)

The admin AI settings accept an "API host", but the model-listing endpoint concatenates api_host + "/v1/models" while the chat client auto-appends /v1. A base URL that already contains /v1 — the normal convention for OpenAI-compatible gateways (SenseNova, SiliconFlow, OneAPI relays, vLLM, SGLang...) — therefore produces /v1/v1/models and fails with the gateway's NOT_FOUND error, which is passed through to the UI verbatim.

Proposal: a shared NormalizeAPIHost() helper (trim whitespace/trailing slashes, append /v1 when missing, keep /v1beta/* endpoints intact) used by both code paths, plus concise upstream error summaries instead of echoing raw response bodies.

2. Per-provider thinking mode switch

Reasoning-capable models are increasingly common (DeepSeek V4, Qwen3, SenseNova, ...). Proposal: an admin switch per AI provider that injects the OpenAI-compatible enable_thinking: true flag into chat completion requests. The existing reasoning_content streaming/rendering path already displays the thought process, so no front-end change is required for display.

3. Per-provider vision (image input) switch

Proposal: an admin switch enabling image attachments in AI conversations — up to 4 PNG/JPEG/WebP images (≤4 MB decoded each) sent as base64 data URLs or HTTPS links, converted to MultiContent parts. The switch is exposed via site info (ai_vision_enabled) so the chat input only shows the attach button for vision-capable providers. History records keep a textual placeholder instead of persisting image data, so no DB schema change is needed.

Scope / non-goals

• No new provider protocols (OpenAI-compatible only); Anthropic removed from the default provider list since the backend speaks the OpenAI protocol.
• No multi-provider routing or per-user model selection.
• No persistence of image attachments in conversation history.

Related

• #1594 (will be closed and resubmitted referencing this issue).
• Regarding the security reminder in #1594: the flagged constant was the base64 of a standard 1×1-pixel PNG placeholder used in a unit test, not a credential. To avoid any misreading, the test now constructs the image at runtime from its signature bytes and the source contains no base64 blob.

Happy to hear feedback on the scope before resubmitting. Thanks!