🔁 AgentLoop

The AI agent starter you can actually read. The full agent loop — streaming + tool use — in ~150 lines. No framework, no 40-file SaaS template to gut. Clone, add a key, deploy.

Quickstart · How it works · Add a tool · Pro

---

The AI-starter shelf is crowded with two kinds of repo: black-box frameworks that hide the loop, and giant SaaS kits you spend a day deleting. AgentLoop is neither. It's the actual agent loop — model calls a tool, you run it, the result goes back, repeat — written plainly enough to learn from and solid enough to build on.

What you get (free, MIT)

• ✅ Streaming chat — tokens render as they arrive. Plain fetch + ReadableStream, zero UI deps, no SDK lock-in.
• ✅ Real tool use — a working agent loop, not a single if.
• ✅ Two example tools (get_current_time, calculate) + a one-function extension point.
• ✅ Typed & commented — Next.js App Router + the official Anthropic SDK. Current with today's Claude models.
• ✅ One-command deploy to Vercel.

Quickstart

git clone https://github.com/mnifzied-create/agentloop.git
cd agentloop
npm install
cp .env.example .env.local      # then paste your ANTHROPIC_API_KEY
npm run dev                     # http://localhost:3000

Get a key at console.anthropic.com. Ask the agent what is (12 * 9) + 7? and watch it call the calculate tool.

Deploy

Set ANTHROPIC_API_KEY in your Vercel project env vars and you're live.

How it works

The whole agent lives in app/api/chat/route.ts:

1. Stream a Claude turn, forwarding text tokens to the browser as they arrive.
2. When the model emits a tool_use block, run the matching tool from lib/tools.ts.
3. Feed the tool result back as the next turn and loop (bounded to 5 steps).
4. Stop when the model returns a normal text answer.

That's the entire pattern behind "AI agents" — no framework required.

Add your own tool

Two edits, one file:

// lib/tools.ts
export const tools = [
  // ...existing tools
  {
    name: "get_weather",
    description: "Get the current weather for a city.",
    input_schema: {
      type: "object",
      properties: { city: { type: "string" } },
      required: ["city"],
    },
  },
];

export async function runTool(name, input) {
  switch (name) {
    // ...existing cases
    case "get_weather":
      return JSON.stringify(await fetchWeather(input.city));
  }
}

Claude reads your description to decide when to call it. That's the whole contract.

Tech

Next.js (App Router) · TypeScript · @anthropic-ai/sdk · zero UI dependencies.

---

🔁 AgentLoop Pro

The free core is the loop. Pro is every pattern you'll reach for next — each one as minimal and readable as the core. Not a bloated SaaS kit; the same teach-by-reading philosophy, leveled up.

Pattern	Free	Pro
Streaming + single-tool loop	✅	✅
Parallel & multi-tool orchestration	—	✅
Structured outputs (typed JSON)	—	✅
Persistent memory (SQLite threads)	—	✅
Retries, timeouts & error handling	—	✅
Human-in-the-loop approval gate	—	✅
Sub-agents / delegation	—	✅
Eval harness (catch regressions)	—	✅
Written guide explaining every pattern	—	✅

→ Get AgentLoop Pro — $29 one-time: ko-fi.com/aimnifzied

_{MIT core. Built in public by an indie dev shipping fast.}