mcp-server-docker

Instructions

Implementation Reference

• src/docker.ts:181-189 (handler)

  The handler function that executes the list_images tool logic. It calls docker.listImages() to fetch Docker images and maps the results to ImageInfo objects with formatted id, tags, size, and created date.

  export async function listImages(): Promise<ImageInfo[]> {
    const images = await docker.listImages();
    return images.map((img) => ({
      id: img.Id.replace("sha256:", "").slice(0, 12),
      tags: img.RepoTags ?? ["<none>"],
      size: formatBytes(img.Size),
      created: new Date(img.Created * 1000).toISOString(),
    }));
  }

• src/docker.ts:24-29 (schema)

  Type definition for the image data returned by the list_images tool, defining the structure of ImageInfo with id, tags, size, and created fields.

  export interface ImageInfo {
    id: string;
    tags: string[];
    size: string;
    created: string;
  }

• src/index.ts:155-173 (registration)

  Registration of the list_images tool with the MCP server. The tool takes no parameters (empty schema {}) and returns a formatted text output of all Docker images.

  server.tool("list_images", "List Docker images on the host.", {}, async () => {
    const images = await listImages();
    return {
      content: [
        {
          type: "text",
          text:
            images.length === 0
              ? "No images found."
              : images
                  .map(
                    (img) =>
                      `${img.id}  ${img.tags.join(", ").padEnd(40)}  ${img.size.padEnd(10)}  ${img.created}`,
                  )
                  .join("\n"),
        },
      ],
    };
  });

• src/docker.ts:31-37 (helper)

  Helper utility function used by listImages to convert raw byte values into human-readable format (B, KB, MB, GB).

  function formatBytes(bytes: number): string {
    if (bytes === 0) return "0 B";
    const k = 1024;
    const sizes = ["B", "KB", "MB", "GB"];
    const i = Math.floor(Math.log(bytes) / Math.log(k));
    return `${(bytes / Math.pow(k, i)).toFixed(1)} ${sizes[i]}`;
  }