nano-banana-pro

Design

Generate or edit a single image via OpenRouter (google/gemini-3.1-flash-image-preview by default). Accepts a text prompt and optional --input-image for image-to-image editing. Trigger when the user asks for an AI image, illustration, concept art, product render, or wants to modify an existing image.

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Prompt to paste

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Source SKILL.md: https://github.com/opensquilla/opensquilla/blob/HEAD/src/opensquilla/skills/bundled/nano-banana-pro/SKILL.md

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Copying this prompt does not install or run the skill. Review third-party files before use. Codex skill guide

nano-banana-pro — single-image generator via OpenRouter

Generates one PNG from a text prompt (optionally seeded with an input image for editing). Used by meta-short-drama for per-shot first-frame generation, but standalone for any single-image request.

Inputs (`with:`)

key	required	default	notes
`prompt`	yes	—	Plain English prompt. Append `--ar 9:16` etc. as text.
`filename`	yes	—	Output path. Relative resolves against process cwd.
`aspect_ratio`	no	`1:1`	One of `1:1`, `3:2`, `2:3`, `4:3`, `3:4`, `16:9`, `9:16`.
`image_size`	no	`1K`	`1K`, `2K`, `4K`. Higher = slower + costlier.
`model`	no	`google/gemini-3.1-flash-image-preview`	Any OpenRouter image-capable model.
`max_retries`	no	`0`	Extra retries on the primary `model` before moving on to `fallback_model`.
`fallback_model`	no	`""`	Tried ONCE after the primary exhausts retries. Empty disables it. Common pick: `google/gemini-3-pro-image-preview`.
`placeholder_on_fail`	no	`no`	`yes` / `no`. When every model refuses, write a 720x1280 solid-colour PNG with a "Scene placeholder" label so a downstream merge step still has a file in this slot.

To pass an input image for edit mode, invoke the script directly with --input-image PATH. The meta-skill engine does not route input images through with: by convention; for edit workflows call the script.

Auth

API-key resolution order (first hit wins):

--api-key CLI argument (rarely used; meta-skills don't pass it)
OPENROUTER_API_KEY environment variable (gateway injects from .env)
OPENSQUILLA_LLM_API_KEY environment variable, only when the effective OpenSquilla LLM provider resolves to openrouter.
llm.api_key or llm.api_key_env from the selected OpenSquilla TOML config file. Config discovery matches GatewayConfig.load: explicit OPENSQUILLA_GATEWAY_CONFIG_PATH first; otherwise ./opensquilla.toml, then default_opensquilla_home()/config.toml. OPENSQUILLA_STATE_DIR changes default_opensquilla_home(), so a state-dir profile does not fall through to ~/.opensquilla. Config-file credentials are consumed only when the selected config's llm.provider is openrouter or omitted.

No Google Gemini key needed — OpenRouter routes the request to the Gemini image model on the user's behalf.

Output

Prints the absolute path of the saved PNG on stdout. Non-zero exit on any error; stderr carries the diagnostic.

Cost / latency

1K ~ 4-8s
2K ~ 8-15s
4K ~ 20-40s
Use 1K for draft, 4K only when the prompt is locked.

Common failures

no OpenRouter API key found → set OPENROUTER_API_KEY, pass --api-key, or configure [llm] provider = "openrouter" with api_key / api_key_env in the selected OpenSquilla config.
OpenRouter returned no image → the model rejected the prompt (content moderation or unsupported request). Rewrite prompt; check IP-safety rules in ai-video-script.
OpenRouter HTTP 402 / 429 → out of credits / rate-limited.

Other versions