List image models

Instructions

Implementation Reference

• src/tools/models.ts:1-41 (handler)

  The registerModelsTool function that registers the 'list_models' MCP tool. The handler iterates over all MODELS and returns JSON with default model and per-model capabilities (sizes, qualities, features).

  import type { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
  import { MODELS, defaultModel } from "../models.js";
  
  export function registerModelsTool(server: McpServer): void {
    server.registerTool(
      "list_models",
      {
        title: "List image models",
        description:
          "List supported OpenAI image models with their capabilities (sizes, qualities, edit/variation support, etc.). Use this before calling generate_image or edit_image to check which options a model accepts.",
        inputSchema: {},
      },
      async () => {
        const rows = Object.values(MODELS).map((m) => ({
          id: m.id,
          family: m.family,
          sizes: m.sizes,
          qualities: m.qualities,
          max_images_per_request: m.maxN,
          supports: {
            edit: m.supportsEdit,
            variation: m.supportsVariation,
            background: m.supportsBackground,
            output_format: m.supportsOutputFormat,
            input_fidelity: m.supportsInputFidelity,
            moderation: m.supportsModeration,
            style: m.supportsStyle,
            url_response: m.supportsUrlResponse,
          },
          notes: m.notes,
        }));
        const payload = {
          default_model: defaultModel(),
          models: rows,
        };
        return {
          content: [{ type: "text", text: JSON.stringify(payload, null, 2) }],
        };
      },
    );
  }

• src/tools/models.ts:6-11 (schema)

  The tool's input schema (empty object, no parameters required) and title/description metadata for the 'list_models' tool.

  "list_models",
  {
    title: "List image models",
    description:
      "List supported OpenAI image models with their capabilities (sizes, qualities, edit/variation support, etc.). Use this before calling generate_image or edit_image to check which options a model accepts.",
    inputSchema: {},

• src/server.ts:19-19 (registration)

  Registration call: registerModelsTool(server) is called during server creation to wire up the 'list_models' tool.

  registerModelsTool(server);

• src/server.ts:5-5 (registration)

  Import of registerModelsTool from ./tools/models.js.

  import { registerModelsTool } from "./tools/models.js";

• src/models.ts:1-113 (helper)

  The MODELS data structure and ModelInfo type that provides the model capability data consumed by the list_models handler.

  export type Model =
    | "gpt-image-1.5"
    | "gpt-image-1"
    | "gpt-image-1-mini"
    | "dall-e-3"
    | "dall-e-2";
  
  export interface ModelInfo {
    id: Model;
    family: "gpt-image" | "dall-e-3" | "dall-e-2";
    sizes: readonly string[];
    qualities: readonly string[];
    maxN: number;
    supportsBackground: boolean;
    supportsOutputFormat: boolean;
    supportsInputFidelity: boolean;
    supportsModeration: boolean;
    supportsStyle: boolean;
    supportsEdit: boolean;
    supportsVariation: boolean;
    supportsUrlResponse: boolean;
    notes: string;
  }
  
  export const MODELS: Record<Model, ModelInfo> = {
    "gpt-image-1.5": {
      id: "gpt-image-1.5",
      family: "gpt-image",
      sizes: ["auto", "1024x1024", "1536x1024", "1024x1536"],
      qualities: ["auto", "low", "medium", "high"],
      maxN: 10,
      supportsBackground: true,
      supportsOutputFormat: true,
      supportsInputFidelity: true,
      supportsModeration: true,
      supportsStyle: false,
      supportsEdit: true,
      supportsVariation: false,
      supportsUrlResponse: false,
      notes: "Latest GPT Image model. Always returns base64; URL response_format is not supported.",
    },
    "gpt-image-1": {
      id: "gpt-image-1",
      family: "gpt-image",
      sizes: ["auto", "1024x1024", "1536x1024", "1024x1536"],
      qualities: ["auto", "low", "medium", "high"],
      maxN: 10,
      supportsBackground: true,
      supportsOutputFormat: true,
      supportsInputFidelity: true,
      supportsModeration: true,
      supportsStyle: false,
      supportsEdit: true,
      supportsVariation: false,
      supportsUrlResponse: false,
      notes: "GPT Image 1. Always returns base64.",
    },
    "gpt-image-1-mini": {
      id: "gpt-image-1-mini",
      family: "gpt-image",
      sizes: ["auto", "1024x1024", "1536x1024", "1024x1536"],
      qualities: ["auto", "low", "medium", "high"],
      maxN: 10,
      supportsBackground: true,
      supportsOutputFormat: true,
      supportsInputFidelity: true,
      supportsModeration: true,
      supportsStyle: false,
      supportsEdit: true,
      supportsVariation: false,
      supportsUrlResponse: false,
      notes: "Smaller/cheaper GPT Image. Always returns base64.",
    },
    "dall-e-3": {
      id: "dall-e-3",
      family: "dall-e-3",
      sizes: ["1024x1024", "1792x1024", "1024x1792"],
      qualities: ["standard", "hd"],
      maxN: 1,
      supportsBackground: false,
      supportsOutputFormat: false,
      supportsInputFidelity: false,
      supportsModeration: false,
      supportsStyle: true,
      supportsEdit: false,
      supportsVariation: false,
      supportsUrlResponse: true,
      notes:
        "DALL·E 3. Generates a single image per request; does not support edits or variations. Deprecated 2026-05-12.",
    },
    "dall-e-2": {
      id: "dall-e-2",
      family: "dall-e-2",
      sizes: ["256x256", "512x512", "1024x1024"],
      qualities: ["standard"],
      maxN: 10,
      supportsBackground: false,
      supportsOutputFormat: false,
      supportsInputFidelity: false,
      supportsModeration: false,
      supportsStyle: false,
      supportsEdit: true,
      supportsVariation: true,
      supportsUrlResponse: true,
      notes: "DALL·E 2. Only model with variations. Deprecated 2026-05-12.",
    },
  };
  
  export function defaultModel(): Model {
    const env = process.env.DALLE_DEFAULT_MODEL as Model | undefined;
    if (env && env in MODELS) return env;
    return "gpt-image-1.5";
  }