Ultimate Gemini MCP

MCP server for Google's Gemini 3.1 Flash Image — fast image generation with advanced reasoning, 512px–4K resolution, up to 14 reference images, Google Search grounding, and automatic thinking mode.

Setup

Claude Desktop

Add to your mcp config (mcp.json / .claude.json):

config.json

{
  "mcpServers": {
    "ultimate-gemini": {
      "command": "uvx",
      "args": ["ultimate-gemini-mcp@latest"],
      "env": {
        "GEMINI_API_KEY": "your-api-key-here"
      }
    }
  }
}

All generated images include invisible SynthID watermarks for authenticity and provenance tracking.

Features

Gemini 3.1 Flash Image

High-Resolution Output: 512px, 1K, 2K, and 4K resolution
Advanced Text Rendering: Legible, stylized text in infographics, menus, diagrams, and logos
Up to 14 Reference Images: Up to 10 objects + 4 characters for style/character consistency
Google Search Grounding: Real-time data (weather, stocks, events, maps)
Google Image Search: Visual context from web images — the model can FIND real images of anything
Thinking Mode: Configurable reasoning - "minimal" (fast) or "high" (best quality)
Transparent Backgrounds: Flip one flag → ready-to-use transparent PNG/WebP cut-outs with a real alpha channel, recovered by a two-pass difference matte (generate on white → edit to black → solve for alpha). True soft edges/glow/glass, no color halo. Pillow only — no extra dependencies. Costs a second model call (~2x).
Dedicated App-Icon / Logo Tool: generate_app_icon forces a square, transparent, 1024px PNG every time — no way to get a non-square or opaque-background icon

This model is different. Unlike traditional image generators that rely solely on training data, Gemini 3.1 Flash has live access to Google Search and Image Search. It can find actual references for products, people, events, or anything that exists online. "Way of Wade 12" → generates the REAL shoe. "Tony Hawk" → finds real photos. Don't over-prompt — let the model cook.

Server Features

Batch Processing: Generate multiple images in parallel (up to 8 concurrent)
26 Expert Prompt Templates: MCP slash commands for photography, cinematics, storyboards, and more
Flexible Aspect Ratios: 14 options — 1:1, 1:4, 1:8, 2:3, 3:2, 3:4, 4:1, 4:3, 4:5, 5:4, 8:1, 9:16, 16:9, 21:9
Configurable via Environment Variables: Output directory, default size, timeouts, and more

Showcase

Photorealistic Capabilities

Jensen Huang — GPU Surfing Jensen surfing on GPU through cyberpunk city

Elon Musk — Mars Chess Match Elon playing chess with robot on Mars

Jensen Huang — GPU Kitchen Jensen cooking with GPU appliances

Elon Musk — Cybertruck Symphony Elon conducting Cybertruck orchestra

Jensen Huang — Underwater Data Center Jensen scuba diving in data center

Elon Musk — SpaceX Skateboarding Elon skateboarding at SpaceX

Google Search Grounding

Current Weather in San Francisco Weather search

Google Image Search

Butterfly on Flower Butterfly image search

Different Resolutions

512px (fastest) Cat 512px

1K Rose 1K

2K Cyberpunk 2K

Quick Start

Prerequisites

Python 3.11+
Google Gemini API key (free tier available)

Installation

Using uvx (recommended — no install needed):

bash

uvx ultimate-gemini-mcp@latest

Note: Use @latest to ensure uv always fetches the newest version from PyPI. Without it, uv may use a cached environment.

Using pip:

Terminal

pip install ultimate-gemini-mcp

From source:

bash

git clone https://github.com/anand-92/ultimate-image-gen-mcp
cd ultimate-image-gen-mcp
uv sync

Config file locations:

macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
Windows: %APPDATA%\Claude\claude_desktop_config.json

macOS spawn uvx ENOENT error: Use the full path — find it with which uvx, then set "command": "/Users/you/.local/bin/uvx".

Claude Code

Terminal

claude mcp add ultimate-gemini \
  --env GEMINI_API_KEY=your-api-key \
  -- uvx ultimate-gemini-mcp@latest

Cursor

Add to .cursor/mcp.json:

config.json

{
  "mcpServers": {
    "ultimate-gemini": {
      "command": "uvx",
      "args": ["ultimate-gemini-mcp@latest"],
      "env": {
        "GEMINI_API_KEY": "your-api-key-here"
      }
    }
  }
}

Images are saved to ~/gemini_images by default. Add "OUTPUT_DIR": "/your/path" to customize.

Tools

`generate_image`

Generate an image with Gemini 3.1 Flash Image.

Parameter	Type	Default	Description
`prompt`	string	required	Text description. Less is more — "Tony Hawk kickflip" beats a long description. The model with search can find references automatically.
`aspect_ratio`	string	`1:1`	One of: `1:1` `1:4` `1:8` `2:3` `3:2` `3:4` `4:1` `4:3` `4:5` `5:4` `8:1` `9:16` `16:9` `21:9`
`image_size`	string	`2K`	`512px`, `1K`, `2K`, or `4K`
`output_format`	string	`png`	`png`, `jpeg`, or `webp`
`reference_image_paths`	list	`[]`	Up to 14 local image paths (10 objects + 4 characters)
`enable_google_search`	bool	`false`	USE THIS for products, people, events — anything that exists now. The model searches Google for real info.
`enable_image_search`	bool	`false`	USE THIS for visual references. The model finds actual images to work from. This is huge — it can reference real photos of anyone/anything.
`thinking_level`	string	`minimal`	`minimal` (fast) or `high` (best quality)
`response_modalities`	list	`["TEXT","IMAGE"]`	`["TEXT","IMAGE"]`, `["IMAGE"]`, or `["TEXT"]`
`transparent_background`	bool	`false`	Produce a transparent PNG/WebP cut-out via the two-pass difference matte (~2x cost; see below)
`preserve_original`	bool	`true`	Also keep the pass-1 (white-background) image, not just the cut-out
`alpha_output_format`	string	`png`	Alpha-capable output format: `png` or `webp`

Image size guide:

512px — fastest, lowest cost (0.5K)
1K — fast, good for testing (~1-2 MB)
2K — recommended for most use cases (~3-5 MB)
4K — maximum quality for production assets (~8-15 MB)

Transparent backgrounds — set one flag, get a real alpha cut-out

Just set transparent_background=true. You get back a ready-to-use transparent PNG/WebP (real alpha channel) at transparent_path — no manual masking, no second tool, no follow-up steps.

Generating an app icon or logo? Use the dedicated generate_app_icon tool instead — it forces square + transparent + 1024px PNG so the icon constraints can't be set wrong.

Under the hood this is a two-pass difference matte. The subject is rendered once on a pure white (#FFFFFF) background, that image is edited to a pure black (#000000) background, and the two frames are combined to solve for alpha per pixel: since obs_white − obs_black = (1−α)·255 on every channel, α = 1 − mean(obs_white − obs_black)/255, and the foreground colour is un-premultiplied from the black frame. Because there's no colour key, there's no green spill/halo; alpha is fractional, so soft edges, glow, glass, and faint shadows all survive. Pillow-only, zero ML downloads — but it costs a second model call (~2x tokens/latency).

The technique assumes the edit pass changed only the background. If the model drifts the subject between passes, the matte degrades — the result still returns (aligned/alignment_error flag it, with a loud post_processing_warnings entry) so you can decide whether to regenerate.

Each returned image gains: transparent_path, background_removed, background_removal_mode ("difference_matte"), aligned, alignment_error, alpha_output_format, and post_processing_warnings. By default the pass-1 (white-background) original is preserved alongside the cut-out (preserve_original=true).

jsonc

// generate_image(prompt="a friendly robot mascot", transparent_background=true)
{
  "images": [{
    "path": "/path/to/a-friendly-robot-mascot-...png",            // pass-1 (white bg)
    "transparent_path": "/path/to/a-friendly-robot-mascot-...-transparent.png",
    "background_removed": true,
    "background_removal_mode": "difference_matte",
    "aligned": true,
    "alignment_error": 0.004,
    "alpha_output_format": "png",
    "post_processing_warnings": []
  }]
}

It nails crisp-edged subjects and soft glow/glass. The one failure mode is the edit pass drifting the subject (flagged via aligned: false) — regenerate if edges look ghosted.

`generate_app_icon`

Purpose-built for app icons and logos. Square, transparent, and 1024px are forced — there is no aspect_ratio, image_size, output_format, or transparent_background knob to get wrong. Every result is a real alpha-channel PNG at transparent_path, ready to drop into a .iconset directory and convert with iconutil -c icns.

Parameter	Type	Default	Description
`prompt`	string	required	Describe the icon/logo mark only — framing & transparency are handled
`reference_image_paths`	str \| list	`null`	Brand/style reference image path(s), up to 14
`enable_google_search`	bool	`false`	Ground design in real web references
`enable_image_search`	bool	`false`	Use Google Image Search for visual context
`thinking_level`	string	`high`	`minimal` or `high` (icons reward `high`)
`allow_icon_words_in_prompt`	bool	`false`	Escape hatch — bypass the prompt guard only when a word like "logo" is genuinely part of the subject

The prompt must describe ONLY the subject, never the deliverable. This tool already turns whatever you describe into an icon, so framing words like "app icon", "logo", "favicon", or "squircle" in the prompt are rejected (set allow_icon_words_in_prompt=true only if such a word is literally part of the depicted subject). Right: "a glowing electric-blue magnifying glass over a network graph". Wrong: "an app icon of a magnifying glass".

jsonc

// generate_app_icon(prompt="a glowing electric-blue magnifying glass over a network graph")
{
  "images": [{
    "transparent_path": "/path/to/...-transparent.png",  // square, 1024px, alpha
    "background_removed": true,
    "alpha_output_format": "png"
  }]
}

`batch_generate`

Generate multiple images in parallel.

Parameter	Type	Default	Description
`prompts`	list	required	List of prompt strings (max 8)
`aspect_ratio`	string	`1:1`	Aspect ratio applied to all images
`image_size`	string	`2K`	Resolution for all images
`output_format`	string	`png`	Format for all images
`response_modalities`	list	`["TEXT","IMAGE"]`	Modalities for all images
`batch_size`	int	`8`	Max concurrent requests
`enable_image_search`	bool	`false`	Use Google Image Search for visual context
`thinking_level`	string	`minimal`	`minimal` or `high`
`transparent_background`	bool	`false`	Apply the two-pass difference matte to every image (each costs a second model call)
`preserve_original`	bool	`true`	Keep the pass-1 (white-background) images too
`alpha_output_format`	string	`png`	Transparent output format: `png` or `webp`

MCP Prompt Templates

26 expert prompt templates are available as MCP slash commands in Claude Code (type / to browse). Each template returns a crafted prompt and recommended parameters ready to pass directly to generate_image or batch_generate. For app icons and logos, use the dedicated generate_app_icon tool instead.

Command	Description	Default aspect ratio
`photography_shot`	Photorealistic shot with lens/lighting specs	16:9
`cinematic_scene`	Film still with cinematography language	21:9
`product_mockup`	Commercial e-commerce photography	1:1 or 4:5
`batch_storyboard`	Multi-scene storyboard → calls `batch_generate`	16:9
`macro_shot`	Extreme macro with micro-snoot lighting	1:1
`fashion_portrait`	Editorial fashion with gobo shadow patterns	4:5
`technical_cutaway`	Stephen Biesty-style cutaway diagram	3:2, 4K, IMAGE only
`flat_lay`	Overhead knolling photography	1:1
`action_freeze`	High-speed strobe with motion blur background	16:9
`night_street`	Moody night street with practical light sources	16:9
`drone_aerial`	Straight-down golden hour aerial	4:5, 4K, IMAGE only
`stylized_3d_render`	UE5-style render with subsurface scattering	1:1, IMAGE only
`sem_microscopy`	Scanning electron microscope false-color	1:1, IMAGE only
`double_exposure`	Silhouette-blended double exposure	2:3, IMAGE only
`architectural_viz`	Ray-traced architectural visualization	3:2, 4K
`isometric_illustration`	Orthographic isometric 3D illustration	1:1, IMAGE only
`food_photography`	High-end backlit food photography	4:5
`motion_blur`	Rear-curtain sync slow shutter sequence	16:9
`typography_physical`	Text embedded in physical environment	16:9, 4K, IMAGE only
`retro_futurism`	1970s cassette-futurism analog sci-fi	4:3, IMAGE only
`surreal_dreamscape`	Surrealist impossible physics scene	1:1, IMAGE only
`character_sheet`	Video game character concept art sheet	3:2, 4K, IMAGE only
`pbr_texture`	Seamless PBR texture map with raking light	1:1, IMAGE only
`historical_photo`	Period-accurate photography with film emulation	4:5
`bioluminescent_nature`	Long-exposure bioluminescence macro	1:1
`silhouette_shot`	Cinematic pure-black silhouette master shot	21:9, 4K

Configuration

Variable	Default	Description
`GEMINI_API_KEY`	—	Required. Google Gemini API key
`OUTPUT_DIR`	`~/gemini_images`	Directory where images are saved
`DEFAULT_IMAGE_SIZE`	`2K`	Default resolution (`1K`, `2K`, `4K`)
`DEFAULT_MODEL`	`gemini-3-pro-image-preview`	Default model
`ENABLE_PROMPT_ENHANCEMENT`	`false`	Auto-enhance prompts by default
`ENABLE_GOOGLE_SEARCH`	`false`	Enable Google Search grounding by default
`REQUEST_TIMEOUT`	`60`	API timeout in seconds
`MAX_BATCH_SIZE`	`8`	Max parallel requests in batch mode
`LOG_LEVEL`	`INFO`	Logging level

Troubleshooting

spawn uvx ENOENT — Claude Desktop can't find uvx. Use the full path:

json

"command": "/Users/yourusername/.local/bin/uvx"

Find it with: which uvx

GEMINI_API_KEY not found — Set the key in your MCP config env block or in a .env file. Get a free key at Google AI Studio.

Content blocked by safety filters — Rephrase the prompt to avoid sensitive content.

Rate limit exceeded — Wait and retry, or upgrade your API quota.

Images not saving — Check OUTPUT_DIR exists and is writable: mkdir -p /your/output/path.

License

MIT — see LICENSE for details.

MCP Registry

mcp-name: io.github.nikships/ultimate-image-gen-mcp

Ultimate Gemini MCP README