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     kolbo-api/src/config/systemPrompt.js (lines ~968–1061).
     When that function changes, update this file in the same session. -->

# Nano Banana — Prompt Rules

Load this file when the user wants a **Nano Banana 2 (Gemini 3.1 Flash Image)** or **Nano Banana Pro (Gemini 3 Pro Image)** image. For other image models see `models/gpt-image.md`, `models/creative-director.md`, or `models/prompt-copilot.md`.

**Kolbo MCP routing:** call `generate_image` or `generate_image_edit`. Pass `model: "nano-banana-2"` or `model: "nano-banana-pro"` when the user named one; otherwise consult `list_models({ type: "text_to_img" })`.

## CRITICAL Kolbo Platform Rules

- **Resolution and aspect ratio are MCP-tool params.** **NEVER include resolution strings ("1K/2K/4K/512px"), aspect-ratio tags ("16:9", "9:16", "1:1"), or any size syntax inside the `prompt` body.** Pass them as separate `aspect_ratio` / `resolution` params.
- Do not write Python / Vertex AI / Gemini SDK code, `generationConfig`, `aspectRatio:`, or any API call syntax. The user is generating through Kolbo's MCP tools.

## Model Awareness (use only to inform recommendations, never in the prompt body)

- **Nano Banana 2 (Gemini 3.1 Flash Image)**: fast, 512px / 1K / 2K / 4K, very wide aspect range incl. 1:4, 4:1, 1:8, 8:1, 21:9, supports real-time web-search grounding. Default for most use cases.
- **Nano Banana Pro (Gemini 3 Pro Image)**: max-fidelity, 1K / 2K / 4K, standard aspect range. Use for posters, brand-final assets, dense text rendering, identity-sensitive edits.
- Both: knowledge cutoff Jan 2025, output includes C2PA Content Credentials + SynthID watermark, support up to 14 reference images in one prompt.

## Best Practices (apply to EVERY prompt)

- **Be specific**: concrete details on subject, lighting, composition. No vague keyword soup.
- **Positive framing**: describe what you WANT, not what you don't ("empty street" not "no cars"; "calm water" not "no waves").
- **Camera control language**: use photographic / cinematic terms ("low angle", "aerial view", "macro", "Dutch tilt", "rack focus").
- **Iterate conversationally**: refine with small follow-ups, not a giant rewrite.
- **Start with a strong verb** that declares the primary operation: `Generate`, `Transform`, `Render`, `Compose`, `Edit`, `Replace`, `Translate`, `Localize`.
- Detect the user's language; reply in their language but write the prompt itself in English.

## The 5 Frameworks

### 1. Text-to-image (no references)
Narrative description, not keyword list. You are the director.
**Formula**: `[Subject] + [Action] + [Location/context] + [Composition] + [Style]`
Example shape: `[Subject] A striking fashion model in a tailored brown dress, sleek boots, structured handbag. [Action] Posing with confidence, slightly turned. [Location] Seamless deep cherry-red studio backdrop. [Composition] Medium-full shot, center-framed. [Style] Editorial fashion magazine, medium-format analog film, pronounced grain, high saturation, cinematic lighting.`

### 2. Multimodal generation (with reference images)
For character consistency, product placement, sketch-to-render, fabric/material transfer, etc.
**Formula**: `[Reference images] + [Relationship instruction] + [New scenario]`
Example shape: `Using @image1 as the structure and @image2 as the texture/style/material, transform this into <output>. Place it in <new scenario>.`
- Reference images by tag (`@image1`, `@image2`, …) and state explicitly what role each plays (structure / texture / palette / character / product) — see `workflows/visual-dna.md`.
- You can mix up to 14 reference images in a single prompt — be explicit about each one's role.

### 3. Image editing
Two modes:
- **Conversational / inpaint (no new references)**: call `generate_image_edit` with a single `source_image`. Surgical edit, explicit preserve list. Use **semantic masking** — define the masked region in plain English ("the man in the foreground", "only the sky behind the building"). Always say what to keep exactly the same. Example: `Remove the man from @image1. Keep the building, sky, lighting, perspective, and all other subjects exactly the same.`
- **With new references**: composition ("add the object from @image2 into @image1, placed on the left counter, lighting matched") or style transfer ("recreate @image1's exact content in the style of @image2 / Van Gogh / 1980s anime cel / etc.").

### 4. Real-time web-search grounding (Nano Banana 2 strength)
Instead of describing a fictional scene, instruct the model to retrieve real-world data and then visualize it.
**Formula**: `[Source/Search request] + [Analytical task] + [Visual translation]`
Example shape: `Search for the current weather and date in San Francisco. Analytically, use this data to modify the scene (e.g., if raining, make it look grey and rainy). Visualize this in a miniature city-in-a-cup concept embedded within a realistic, modern smartphone UI.`
- Use when the user asks for "today's weather", "current price", "live data", "what's playing now", "as of right now", etc.
- Recommend Nano Banana 2 (Flash) for this — Pro doesn't add value here.

### 5. Text rendering & localization (both models excel)
- **Always quote** literal text: `"Happy Birthday"`, `"URBAN EXPLORER"`, `"10% OFF"`.
- **Describe typography** explicitly: "bold white sans-serif", "Century Gothic 12px", "flowing Brush Script", "heavy blocky Impact font". You can use ALL CAPS to emphasize render style.
- **Multilingual**: write the prompt in English and specify the target language for the in-image text ("Then render the same text in Korean and Arabic").
- **Text-first hack**: when text is the hero, recommend the user first conversationally generate the copy/concepts, THEN ask for the image with that text — better typographic fidelity.
- Cut-out / negative-space text trick: `bold letters spell "<WORD>", filling the center of the frame. The text acts as a cut-out window. A photograph of <scene> is visible ONLY inside the letterforms.`
- For small / dense / multi-font text → recommend `resolution: "2K"` or `"4K"` + Nano Banana Pro.

## Prompt Like a Creative Director (the upgrade layer)

Layer these onto any framework to lift good → breathtaking.

### Lighting (design it, don't just name it)
- **Studio**: "three-point softbox setup", "ring light at eye level", "rim light from camera-left".
- **Dramatic**: "chiaroscuro lighting with harsh high contrast", "single Rembrandt key from the right", "underlit horror-key from below".
- **Natural**: "golden hour backlighting with long shadows", "overcast diffused light", "blue-hour twilight ambient".

### Camera, lens, focus (hardware = visual DNA)
- **Hardware vibe**: `GoPro` for distorted action immersion · `Fujifilm` for authentic color science · `disposable camera` for raw nostalgic flash · `Hasselblad medium format` for editorial fashion · `iPhone` for everyday realism · `ARRI ALEXA` for cinematic.
- **Lens / focus**: "low-angle shot, shallow depth of field f/1.8", "wide-angle for vast scale", "macro for intricate detail", "85mm portrait compression", "anamorphic 2.39:1 bokeh".

### Color grading & film stock (emotional tone)
- Nostalgic / gritty: "as if shot on 1980s color film, slightly grainy", "expired Kodak Gold", "VHS color bleed".
- Modern / moody: "cinematic color grading with muted teal tones", "high-contrast bleach bypass", "warm amber + cool steel-blue duotone".
- Editorial: "professional color grading, rich saturation, no clipping in highlights".

### Materiality & texture (specify physical makeup)
- Don't say "suit" — say "navy blue tweed with subtle herringbone".
- Don't say "armor" — say "ornate elven plate armor etched with silver leaf patterns".
- Don't say "mug" — say "minimalist matte ceramic coffee mug with a hairline rim".
- This applies to logos, products, characters, environments.

## Output Discipline

- Pass the prompt as the `prompt` field on `generate_image` / `generate_image_edit`.
- **NEVER** include resolution / size / aspect / "9:16" / "2K" inside the prompt body.
- When summarizing the call to the user, state separately:
  - **Model:** Nano Banana 2 (Flash) or Nano Banana Pro — with a one-line why
  - **Aspect / Resolution preset:** `<1:1 | 3:2 | 2:3 | 4:3 | 3:4 | 4:5 | 5:4 | 9:16 | 16:9 | 21:9 | 1:4 | 4:1 | 1:8 | 8:1>` + `<1K | 2K | 4K | 512px>` — one-line why
  - **Why this works:** 1 line on the key creative-director choice (lens / lighting / material / framework)
- For follow-up tweaks, write a short conversational edit prompt rather than re-doing the whole thing.
