GitHub Repo Explainer

curl "https://your-worker.workers.dev/repo?url=https://github.com/cloudflare/workers-sdk"

{
  "summary": "Workers SDK is the official development toolkit for building Cloudflare Workers. It provides CLI tools, TypeScript types, and local development servers for developers building serverless applications on Cloudflare's edge network. The project includes Wrangler, the primary CLI for managing Workers, along with templates and testing utilities.",
  "mainTechnologies": [
    "TypeScript",
    "Node.js",
    "Vitest",
    "esbuild",
    "Miniflare",
    "WebAssembly",
    "Service Workers API"
  ],
  "howItWorks": "The SDK is organized as a monorepo containing Wrangler CLI, Miniflare local simulator, and supporting packages. Wrangler provides commands for building, testing, and deploying Workers, while Miniflare simulates the Workers runtime locally. Developers write TypeScript/JavaScript, and the toolchain bundles and deploys to Cloudflare's edge. To run: install dependencies with `pnpm install`, build with `pnpm run build`, and test with `pnpm test`.",
  "keyFeatures": [
    "Wrangler CLI for Worker development and deployment",
    "Local development server with hot reload",
    "TypeScript type definitions for Workers APIs",
    "Miniflare local runtime simulator",
    "D1 database and KV storage integration",
    "Tail logs and real-time debugging",
    "Pages deployment support"
  ],
  "projectStructure": "Monorepo with packages/ directory containing Wrangler, Miniflare, and shared libraries. Source code lives in packages/*/src/, with TypeScript configs at the root. Each package has its own package.json and build configuration.",
  "gettingStarted": "Install pnpm globally, then run `pnpm install` in the repo root. Build all packages with `pnpm run build`. Run tests with `pnpm test`. For Wrangler development, use `pnpm --filter wrangler dev`. See the Wrangler documentation at developers.cloudflare.com/workers/wrangler/.",
  "notableDependencies": [
    "esbuild",
    "miniflare",
    "vitest",
    "unenv",
    "nanoid",
    "undici",
    "@cloudflare/workers-types"
  ],
  "useCases": [
    "Developing Cloudflare Workers applications",
    "Testing Workers locally before deployment",
    "Managing Workers projects with CLI automation",
    "Building edge-first serverless applications"
  ]
}

{
  "error": "Missing query parameter: url",
  "code": "INVALID_URL"
}

{
  "error": "Invalid GitHub repo URL",
  "code": "INVALID_URL"
}

{
  "error": "Failed to fetch or explain repo",
  "code": "FETCH_OR_AI_ERROR"
}

// From src/lib/github.ts
export const GITHUB_API_BASE = "https://api.github.com";
export const MAX_CONTENT_CHARS = 24_000;

const COMMON_HEADERS = {
  "User-Agent": "Cloudflare-Experiments-GithubRepoExplainer/1.0",
};

const priorityNames = [
  "package.json", "package-lock.json", "Cargo.toml", "pyproject.toml", "go.mod",
  "tsconfig.json", "vite.config.ts", "vite.config.js", "next.config.js", "next.config.mjs",
];

// From src/constants/defaults.ts
export const AI_MODEL = "@cf/meta/llama-3.1-8b-instruct";
export const AI_MAX_TOKENS = 2048;
export const FETCH_TIMEOUT_MS = 15_000;

app.get("/repo", async (c) => {
  const urlParam = c.req.query("url");
  if (!urlParam?.trim()) return jsonError(c, "Missing query parameter: url", "INVALID_URL");

  const parsed = parseRepoUrl(urlParam);
  if (!parsed) return jsonError(c, "Invalid GitHub repo URL", "INVALID_URL");

  try {
    const content = await fetchRepoContent(parsed.owner, parsed.repo);
    const result = await explainRepo(c.env, parsed.owner, parsed.repo, content);
    return jsonSuccess(c, result);
  } catch (e) {
    const message = e instanceof Error ? e.message : "Failed to fetch or explain repo";
    return jsonError(c, message, "FETCH_OR_AI_ERROR", 502);
  }
});

const prompt = `You are a technical explainer. Analyze the following content from the GitHub repo "${owner}/${repo}" (README and key files).

CRITICAL: Your entire response must be exactly one valid JSON object. Do not output any text before or after it. Do not wrap in markdown or code blocks. Do not say "Here is the JSON". Start your response with { and end with }.

Use exactly these keys (all required):

1. "summary": A substantive paragraph (4-6 sentences) describing what the project is, who it's for, and what problem it solves...

2. "mainTechnologies": Array of 5-15 strings: languages, frameworks, runtimes, build tools...

[... 6 more detailed field specifications ...]

Content:
${context}`;

name = "github-repo-explainer"
main = "src/index.ts"
compatibility_date = "2024-01-01"

[ai]
binding = "AI"

{
  "dependencies": {
    "hono": "^4.6.12",
    "jsonrepair": "^3.13.2"
  },
  "devDependencies": {
    "@cloudflare/workers-types": "^4.20241127.0",
    "typescript": "^5.7.2",
    "wrangler": "^4"
  }
}

const priorityNames = [
  "package.json",
  "requirements.txt", // Add Python projects
  "Dockerfile",       // Add Docker configs
  "README.md",
  // ... your custom files
];