Nano Banana MCP Server

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generate_image

Create images from text descriptions using Google's Gemini AI model. Save generated images to a specified directory for use in projects or visual content creation.

Instructions

Generate images using Google Gemini Nano Banana Pro (gemini-3-pro-image-preview) model

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "prompt": "<prompt>"
    },
    "name": "generate_image"
  }
}

Input Schema

Name	Required	Description	Default
`prompt`	Yes	Text description of the image to generate
`output_dir`	No	Directory to save the generated image(s)	.

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Feb 20, 2026

TDQS

C2.9/5.0

Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations provided, the description carries the full burden of behavioral disclosure. It mentions the model but fails to describe key traits like rate limits, authentication needs, output format (e.g., image type), or whether the operation is idempotent. This leaves significant gaps for a generative AI tool.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is a single, efficient sentence with zero wasted words. It's front-loaded with the core function and includes necessary model specification, making it appropriately concise for this tool.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the complexity of an image generation tool with no annotations and no output schema, the description is inadequate. It lacks details on behavioral traits, usage context, and output handling, leaving the agent with insufficient information to invoke it effectively beyond basic parameter passing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so the schema fully documents both parameters. The description adds no additional parameter semantics beyond what's in the schema, such as prompt formatting tips or output_dir constraints. Baseline 3 is appropriate when the schema handles parameter documentation.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool's function with a specific verb ('Generate') and resource ('images'), specifying the model used ('Google Gemini Nano Banana Pro'). However, with no sibling tools mentioned, it cannot demonstrate differentiation from alternatives, though it's not required in this context.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description provides no guidance on when to use this tool versus alternatives, prerequisites, or contextual constraints. It simply states what the tool does without indicating appropriate scenarios or limitations.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

Deploy Server

Other Tools

generate_imageC