The live v1beta API rejects the legacy responseFormat.image block
(enum-based aspectRatio/imageSize fields) for gemini-3.1-flash-lite-image
with INVALID_ARGUMENT, even for documented plain-string values. Gemini
Flash image models accept plain-string hints under
generationConfig.imageConfig instead (e.g. aspectRatio 16:9, imageSize
1K), which the API accepts. Switch the flash path to imageConfig and
update the provider tests accordingly. Other providers (aihubmix,
ollama, imagen) are untouched.
Address review feedback that the capability checks were broader than the
documented per-model matrix:
- Drop the extreme aspect ratios (1:4, 4:1, 1:8, 8:1) from the Flash
allow-list. They are only documented for 3.1 Flash / Flash Lite, so the
global set could send an unsupported ratio to 2.5 Flash Image or 3.1 Pro
Image. Keep the ratios common to every Flash image model.
- Identify imageSize support positively via "gemini-3" instead of excluding
"2.5". The old predicate also matched gemini-2.0-flash-preview-image-
generation, which (with the default 1K size) altered that model's request
shape even though only Gemini 3+ image models accept a configurable size.
Add tests for the gemini-2.0 image-size drop and the extreme-ratio drop.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The Gemini Flash image path (`generateContent`) dropped both `aspect_ratio`
and `image_size`: `generate()` never forwarded them and
`_generate_gemini_flash` did not accept them, so every request fell back to
1:1 / input-matched output. The Imagen path was unaffected.
Forward the hints and emit them under
`generationConfig.responseFormat.image` per the current Gemini API. Aspect
ratio is validated against the accepted set; `imageSize` is validated against
{512,1K,2K,4K} and only sent to Gemini 3+ image models, since
`gemini-2.5-flash-image` supports only `aspectRatio`.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Maintainer edit: preserve provider-specific size hints for custom image generation endpoints while keeping the default 1K mapping compatible. Clarify the custom provider contract in docs and cover response_format/size overrides in tests.
Maintainer edit: require providers.custom.apiBase before making custom image requests and allow unauthenticated local endpoints by omitting Authorization when no apiKey is configured.
Add two new image generation providers:
- `openai` — uses the standalone OpenAI Images API
(`/v1/images/generations`) with an API key. Supports DALL-E
and gpt-image-* models, with automatic parameter adjustment
(gpt-image models don't accept response_format or n).
- `openai_codex` — uses the Codex Responses API with the
`image_generation` tool, authenticated via OAuth subscription
token. The same mechanism ChatGPT uses internally.
Also remove the API key pre-check in ImageGenerationTool so
providers that handle their own auth fallback (like Codex OAuth)
can work without a configured key.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Adds GeminiImageGenerationClient covering both Imagen 4 (:predict) and
Gemini Flash (:generateContent), wires the gemini ProviderConfig through
the SDK, API server, and gateway entry points, and updates the
image-generation docs and skill. Errors from the Gemini endpoints are
logged and surface with the HTTP status and parsed message instead of an
empty string.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
