# Claude agent vs Claude Code: which one are you actually building?

> Source: <https://dev.to/zied_mnif_2f4225fb8d70342/claude-agent-vs-claude-code-which-one-are-you-actually-building-5ek9>
> Published: 2026-06-05 00:02:54+00:00

Search "claude agent boilerplate" and you'll drown in Claude **Code** results — the agentic CLI, `CLAUDE.md`

files, slash commands, hooks. Great tools. But none of that is what you want if you're trying to **build your own agent** on the Anthropic SDK.

Here's the disambiguation, and the ~40 lines that are actually the whole thing.

Most "agent frameworks" just hide that loop from you. It's small enough that you don't need them.

``` python
import Anthropic from "@anthropic-ai/sdk";
const client = new Anthropic();

async function runAgent(userText, tools, runners) {
  const messages = [{ role: "user", content: userText }];

  for (let i = 0; i < 10; i++) {
    const res = await client.messages.create({
      model: "claude-sonnet-4-6",
      max_tokens: 1024,
      tools,
      messages,
    });

    messages.push({ role: "assistant", content: res.content });

    // No tool requested -> the model is done.
    if (res.stop_reason !== "tool_use") {
      return res.content.filter((b) => b.type === "text").map((b) => b.text).join("");
    }

    // Run every tool it asked for this turn, collect one result each.
    const results = [];
    for (const block of res.content) {
      if (block.type === "tool_use") {
        const out = await runners[block.name](block.input);
        results.push({ type: "tool_result", tool_use_id: block.id, content: out });
      }
    }
    messages.push({ role: "user", content: results });
  }
}
```

That's it. The four things people get wrong:

`tool_result`

per request, matched by `tool_use_id`

.If you'd rather start from a streaming Next.js app you can deploy in one command, I open-sourced exactly this (MIT): ** AgentLoop** — the whole agent in ~150 readable lines, no framework. Clone it, add a key, deploy.

There's a $29 Pro pack for the patterns you hit in production (parallel tools, persistent memory, retries, rate limiting, approval gates, evals, token metering, and a multi-provider seam so it runs on any model) — but the free core stands alone forever.

Build the loop. Own it. Don't import a black box.