opencode-anthropic-proxy/claude-proxy.mjs

import http from "node:http";
import { execFile } from "node:child_process";
import { promisify } from "node:util";

const execFileAsync = promisify(execFile);

const PORT = process.env.CLAUDE_PROXY_PORT || 3000;

const MODEL_MAP = {
  "claude-opus-4-7": "opus",
  "claude-sonnet-4-6": "sonnet",
  "claude-haiku-4-5": "haiku",
};

const TOOL_MAP = {
  bash: "Bash",
  read: "Read",
  write: "Write",
  edit: "Edit",
  glob: "Glob",
  grep: "Grep",
  webfetch: "WebFetch",
  websearch: "WebSearch",
  question: "Question",
  task: "Task",
  todowrite: "TodoWrite",
  skill: "Skill",
};

function parseBody(req) {
  return new Promise((resolve, reject) => {
    const chunks = [];
    req.on("data", (c) => chunks.push(c));
    req.on("end", () => {
      try {
        resolve(JSON.parse(Buffer.concat(chunks).toString()));
      } catch (e) {
        reject(e);
      }
    });
    req.on("error", reject);
  });
}

function buildMessages(body) {
  const messages = body.messages || [];
  const parts = [];
  for (const msg of messages) {
    if (msg.role === "system") {
      parts.push(`System: ${msg.content}`);
    } else if (msg.role === "user") {
      parts.push(`User: ${msg.content}`);
    } else if (msg.role === "assistant") {
      parts.push(`Assistant: ${msg.content}`);
    }
  }
  return parts.join("\n\n");
}

function extractTools(body) {
  const tools = body.tools || [];
  const claudeTools = [];
  for (const tool of tools) {
    const name = tool.function?.name || tool.name;
    if (name) {
      const mapped = TOOL_MAP[name.toLowerCase()] || name;
      claudeTools.push(mapped);
    }
  }
  return claudeTools;
}

async function callClaude(prompt, model, allowedTools) {
  const modelWithoutPrefix = model.includes("/") ? model.split("/").pop() : model;
  const modelAlias = MODEL_MAP[modelWithoutPrefix] || modelWithoutPrefix;
  const args = ["-p", prompt, "--model", modelAlias, "--no-session-persistence", "--output-format", "json", "--permission-mode", "bypassPermissions"];
  if (allowedTools.length > 0) {
    args.push("--allowedTools", ...allowedTools);
  }
  const { stdout } = await execFileAsync("/home/kenny/.local/bin/claude", args, {
    timeout: 300000,
    maxBuffer: 1024 * 1024 * 10,
  });
  return JSON.parse(stdout);
}

async function handleRequest(req, res) {
  if (req.method === "GET" && req.url === "/v1/models") {
    res.writeHead(200, { "Content-Type": "application/json" });
    res.end(JSON.stringify({
      object: "list",
      data: Object.keys(MODEL_MAP).map((id) => ({
        id,
        object: "model",
        created: Math.floor(Date.now() / 1000),
        owned_by: "anthropic",
      })),
    }));
    return;
  }

  if (req.method !== "POST" || !req.url.startsWith("/v1/chat/completions")) {
    res.writeHead(404, { "Content-Type": "application/json" });
    res.end(JSON.stringify({ error: "Not found" }));
    return;
  }

  try {
    const body = await parseBody(req);
    const prompt = buildMessages(body);
    const model = body.model || "claude-sonnet-4-6";
    const stream = body.stream || false;
    const allowedTools = extractTools(body);

    const result = await callClaude(prompt, model, allowedTools);

    const response = {
      id: `chatcmpl-${Date.now()}`,
      object: "chat.completion",
      created: Math.floor(Date.now() / 1000),
      model,
      choices: [
        {
          index: 0,
          message: {
            role: "assistant",
            content: result.result || result.content || JSON.stringify(result),
          },
          finish_reason: "stop",
        },
      ],
      usage: {
        prompt_tokens: result.usage?.input_tokens || 0,
        completion_tokens: result.usage?.output_tokens || 0,
        total_tokens: (result.usage?.input_tokens || 0) + (result.usage?.output_tokens || 0),
      },
    };

    if (stream) {
      res.writeHead(200, {
        "Content-Type": "text/event-stream",
        "Cache-Control": "no-cache",
        "Connection": "keep-alive",
      });
      const chunk = {
        id: response.id,
        object: "chat.completion.chunk",
        created: response.created,
        model: response.model,
        choices: [{ index: 0, delta: { role: "assistant", content: response.choices[0].message.content }, finish_reason: null }],
      };
      res.write(`data: ${JSON.stringify(chunk)}\n\n`);
      const endChunk = {
        id: response.id,
        object: "chat.completion.chunk",
        created: response.created,
        model: response.model,
        choices: [{ index: 0, delta: {}, finish_reason: "stop" }],
      };
      res.write(`data: ${JSON.stringify(endChunk)}\n\n`);
      res.write("data: [DONE]\n\n");
      res.end();
    } else {
      res.writeHead(200, { "Content-Type": "application/json" });
      res.end(JSON.stringify(response));
    }
  } catch (err) {
    console.error(`[${new Date().toISOString()}] Proxy error:`, err);
    res.writeHead(500, { "Content-Type": "application/json" });
    res.end(JSON.stringify({ error: err.message }));
  }
}

const server = http.createServer(handleRequest);
server.listen(PORT, () => {
  console.log(`Claude proxy listening on http://localhost:${PORT}`);
});