Claude Code clone

import os, json, subprocess
from openai import OpenAI

client = OpenAI(base_url="https://api.opper.ai/v3/compat", api_key=os.environ["OPPER_API_KEY"])
WORKDIR = "workspace"
os.makedirs(WORKDIR, exist_ok=True)

def read_file(path):
    p = os.path.join(WORKDIR, path)
    return open(p).read() if os.path.exists(p) else f"(no file at {path})"

def write_file(path, content):
    with open(os.path.join(WORKDIR, path), "w") as f:
        f.write(content)
    return f"Wrote {len(content)} bytes to {path}"

def run_command(command):
    r = subprocess.run(command, shell=True, cwd=WORKDIR, capture_output=True, text=True, timeout=30)
    return (r.stdout + r.stderr).strip() or "(no output)"

TOOLS = {"read_file": read_file, "write_file": write_file, "run_command": run_command}

specs = [
    {"type": "function", "function": {"name": "read_file", "description": "Read a file in the workspace.",
        "parameters": {"type": "object", "properties": {"path": {"type": "string"}}, "required": ["path"]}}},
    {"type": "function", "function": {"name": "write_file", "description": "Create or overwrite a file in the workspace.",
        "parameters": {"type": "object", "properties": {"path": {"type": "string"}, "content": {"type": "string"}}, "required": ["path", "content"]}}},
    {"type": "function", "function": {"name": "run_command", "description": "Run a shell command in the workspace and return its output.",
        "parameters": {"type": "object", "properties": {"command": {"type": "string"}}, "required": ["command"]}}},
]

SYSTEM = (
    "You are a coding agent. Use the tools to read, write, and run code in the "
    "workspace until the task is done. Verify your work, then give a short summary."
)

messages = [{"role": "system", "content": SYSTEM}]

def send(user_message):
    messages.append({"role": "user", "content": user_message})
    # Keep going while the model wants to call tools.
    while True:
        r = client.chat.completions.create(model="anthropic/claude-sonnet-4-6", messages=messages, tools=specs)
        msg = r.choices[0].message
        messages.append(msg)
        if not msg.tool_calls:
            return msg.content
        for call in msg.tool_calls:
            args = json.loads(call.function.arguments)
            print(f"  · {call.function.name}")
            messages.append({"role": "tool", "tool_call_id": call.id,
                             "content": TOOLS[call.function.name](**args)})

print(send("Write fizzbuzz.py with a fizzbuzz(n) function, then run it for n=15."))
print(send("Now add a test that fizzbuzz(5) ends with 'Buzz', and run it."))

import OpenAI from "openai";
import { readFileSync, writeFileSync, existsSync, mkdirSync } from "node:fs";
import { execSync } from "node:child_process";
import path from "node:path";

const client = new OpenAI({ baseURL: "https://api.opper.ai/v3/compat", apiKey: process.env.OPPER_API_KEY });
const WORKDIR = "workspace";
if (!existsSync(WORKDIR)) mkdirSync(WORKDIR);

const TOOLS: Record<string, (args: any) => string> = {
  read_file: ({ path: p }) =>
    existsSync(path.join(WORKDIR, p)) ? readFileSync(path.join(WORKDIR, p), "utf8") : `(no file at ${p})`,
  write_file: ({ path: p, content }) => {
    writeFileSync(path.join(WORKDIR, p), content);
    return `Wrote ${content.length} bytes to ${p}`;
  },
  run_command: ({ command }) => {
    try {
      return execSync(command, { cwd: WORKDIR, timeout: 30000 }).toString().trim() || "(no output)";
    } catch (e: any) {
      return ((e.stdout?.toString() || "") + (e.stderr?.toString() || "")).trim() || String(e);
    }
  },
};

const specs = [
  { type: "function" as const, function: { name: "read_file", description: "Read a file in the workspace.", parameters: { type: "object", properties: { path: { type: "string" } }, required: ["path"] } } },
  { type: "function" as const, function: { name: "write_file", description: "Create or overwrite a file in the workspace.", parameters: { type: "object", properties: { path: { type: "string" }, content: { type: "string" } }, required: ["path", "content"] } } },
  { type: "function" as const, function: { name: "run_command", description: "Run a shell command in the workspace and return its output.", parameters: { type: "object", properties: { command: { type: "string" } }, required: ["command"] } } },
];

const SYSTEM =
  "You are a coding agent. Use the tools to read, write, and run code in the " +
  "workspace until the task is done. Verify your work, then give a short summary.";

const messages: any[] = [{ role: "system", content: SYSTEM }];

async function send(userMessage: string) {
  messages.push({ role: "user", content: userMessage });
  // Keep going while the model wants to call tools.
  while (true) {
    const r = await client.chat.completions.create({ model: "anthropic/claude-sonnet-4-6", messages, tools: specs });
    const msg = r.choices[0].message;
    messages.push(msg);
    if (!msg.tool_calls) return msg.content;
    for (const call of msg.tool_calls) {
      const args = JSON.parse(call.function.arguments);
      console.log(`  · ${call.function.name}`);
      messages.push({ role: "tool", tool_call_id: call.id, content: TOOLS[call.function.name](args) });
    }
  }
}

console.log(await send("Write fizzbuzz.js with a fizzbuzz(n) function, then run it with node for n=15."));
console.log(await send("Now add a test that fizzbuzz(5) ends with 'Buzz', and run it with node."));

pip install openai
export OPPER_API_KEY="your-api-key"
python app.py

npm install openai
export OPPER_API_KEY="your-api-key"
npx tsx app.ts