Nano Banana

Instructions

Implementation Reference

• mcp-server/src/server.ts:584-597 (handler)

  Executes the generate_diagram tool by constructing a specialized prompt and delegating to the ImageGenerator for actual image creation.

  case "generate_diagram": {
    const diagramRequest: ImageGenerationRequest = {
      prompt: this.buildDiagramPrompt(args),
      outputCount: 1,
      mode: "generate",
      preview: args?.preview as boolean,
      noPreview:
        (args?.noPreview as boolean) ||
        (args?.["no-preview"] as boolean),
    };
    response =
      await this.imageGenerator.generateTextToImage(diagramRequest);
    break;
  }

• mcp-server/src/server.ts:395-459 (registration)

  Registers the generate_diagram tool with its input schema in the list of available tools.

  {
    name: "generate_diagram",
    description:
      "Generate technical diagrams, flowcharts, and architectural mockups",
    inputSchema: {
      type: "object",
      properties: {
        prompt: {
          type: "string",
          description: "Description of the diagram content and structure",
        },
        type: {
          type: "string",
          enum: [
            "flowchart",
            "architecture",
            "network",
            "database",
            "wireframe",
            "mindmap",
            "sequence",
          ],
          description: "Type of diagram to generate",
          default: "flowchart",
        },
        style: {
          type: "string",
          enum: ["professional", "clean", "hand-drawn", "technical"],
          description: "Visual style of the diagram",
          default: "professional",
        },
        layout: {
          type: "string",
          enum: ["horizontal", "vertical", "hierarchical", "circular"],
          description: "Layout orientation",
          default: "hierarchical",
        },
        complexity: {
          type: "string",
          enum: ["simple", "detailed", "comprehensive"],
          description: "Level of detail in the diagram",
          default: "detailed",
        },
        colors: {
          type: "string",
          enum: ["mono", "accent", "categorical"],
          description: "Color scheme",
          default: "accent",
        },
        annotations: {
          type: "string",
          enum: ["minimal", "detailed"],
          description: "Label and annotation level",
          default: "detailed",
        },
        preview: {
          type: "boolean",
          description:
            "Automatically open generated images in default viewer",
          default: false,
        },
      },
      required: ["prompt"],
    },
  },

• mcp-server/src/server.ts:666-681 (helper)

  Helper function that builds a detailed, specialized prompt string for generating diagrams based on user arguments.

  private buildDiagramPrompt(args?: DiagramPromptArgs): string {
    const basePrompt = args?.prompt || "system diagram";
    const type = args?.type || "flowchart";
    const style = args?.style || "professional";
    const layout = args?.layout || "hierarchical";
    const complexity = args?.complexity || "detailed";
    const colors = args?.colors || "accent";
    const annotations = args?.annotations || "detailed";
  
    let prompt = `${basePrompt}, ${type} diagram, ${style} style, ${layout} layout`;
    prompt += `, ${complexity} level of detail, ${colors} color scheme`;
    prompt += `, ${annotations} annotations and labels`;
    prompt += ", clean technical illustration, clear visual hierarchy";
  
    return prompt;
  }

• mcp-server/src/types.ts:64-72 (schema)

  TypeScript interface defining the shape of arguments for the diagram prompt builder, matching the tool's inputSchema.

  export interface DiagramPromptArgs {
    prompt?: string;
    type?: string;
    style?: string;
    layout?: string;
    complexity?: string;
    colors?: string;
    annotations?: string;
  }