build.ts

import { z } from "zod";
import type { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { compactDualOutput, assertNoFlagInjection, INPUT_LIMITS } from "@paretools/shared";
import { docker } from "../lib/docker-runner.js";
import { parseBuildOutput } from "../lib/parsers.js";
import { formatBuild, compactBuildMap, formatBuildCompact } from "../lib/formatters.js";
import { DockerBuildSchema } from "../schemas/index.js";

export function registerBuildTool(server: McpServer) {
  server.registerTool(
    "build",
    {
      title: "Docker Build",
      description:
        "Builds a Docker image and returns structured build results including image ID, duration, and errors. Use instead of running `docker build` in the terminal.",
      inputSchema: {
        path: z
          .string()
          .max(INPUT_LIMITS.PATH_MAX)
          .optional()
          .describe("Build context path (default: cwd)"),
        tag: z
          .string()
          .max(INPUT_LIMITS.SHORT_STRING_MAX)
          .optional()
          .describe("Image tag (e.g., myapp:latest)"),
        file: z
          .string()
          .max(INPUT_LIMITS.PATH_MAX)
          .optional()
          .describe("Dockerfile path (default: Dockerfile)"),
        args: z
          .array(z.string().max(INPUT_LIMITS.STRING_MAX))
          .max(INPUT_LIMITS.ARRAY_MAX)
          .optional()
          .default([])
          .describe("Additional build arguments"),
        compact: z
          .boolean()
          .optional()
          .default(true)
          .describe(
            "Auto-compact when structured output exceeds raw CLI tokens. Set false to always get full schema.",
          ),
      },
      outputSchema: DockerBuildSchema,
    },
    async ({ path, tag, file, args, compact }) => {
      if (tag) assertNoFlagInjection(tag, "tag");
      if (file) assertNoFlagInjection(file, "file");
      for (const a of args ?? []) {
        assertNoFlagInjection(a, "args");
      }

      const cwd = path || process.cwd();
      const dockerArgs = ["build", "."];
      if (tag) dockerArgs.push("-t", tag);
      if (file) dockerArgs.push("-f", file);
      if (args) dockerArgs.push(...args);

      const start = Date.now();
      const result = await docker(dockerArgs, cwd);
      const duration = Math.round((Date.now() - start) / 100) / 10;

      const data = parseBuildOutput(result.stdout, result.stderr, result.exitCode, duration);
      return compactDualOutput(
        data,
        result.stdout,
        formatBuild,
        compactBuildMap,
        formatBuildCompact,
        compact === false,
      );
    },
  );
}