Duel Agents Routing

Duel Agents Routing

Skill by ara.so — AI Agent Skills collection.

Overview

Duel Agents is an IDE-native routing layer that runs prompts against multiple LLM models simultaneously and selects the cheapest answer that meets quality thresholds. It provides:

• Automatic model selection via duel-auto model name
• Cost optimization by choosing cheaper models when quality is sufficient
• OpenAI-compatible and Anthropic-compatible APIs
• IDE integrations for Claude Code, Cursor, Codex, and OpenClaw
• TypeScript SDK for building custom agents and applications

The service routes traffic through https://duelagents.com/v1 using Duel API keys (duel_<prefix>_<secret>).

Prerequisites

You must have a Duel API key. Raw Anthropic or OpenAI keys will not work.

1. Subscribe at https://duelagents.com/dashboard/settings
2. Create an API key from the dashboard
3. Key format: duel_ + 8 characters + _ + 32 characters

Installation

Quick Start (All Tools)

# Set your API key
export DUEL_API_KEY=duel_yourprefix_yoursecret

# Install for all supported tools
npx @duel-agents/install all

# Verify installation
npx @duel-agents/install doctor

Per-Tool Installation

# Claude Code
npx @duel-agents/install claude-code

# Cursor IDE
npx @duel-agents/install cursor

# Codex CLI
npx @duel-agents/install codex

# OpenClaw
npx @duel-agents/install openclaw

SDK for Custom Applications

npm install @duel-agents/sdk

Configuration

Environment Variables

Setting Environment Variables

.env file:

DUEL_API_KEY=duel_abc12345_def67890ghijklmnopqrstuvwxyz12

Shell export:

export DUEL_API_KEY=duel_abc12345_def67890ghijklmnopqrstuvwxyz12

SDK Usage

OpenAI-Compatible API

import { DuelClient } from "@duel-agents/sdk";

const duel = new DuelClient({
  apiKey: process.env.DUEL_API_KEY!, // required
});

// Chat completions
const response = await duel.chat.completions.create({
  model: "duel-auto", // automatic model selection
  messages: [
    { role: "system", content: "You are a helpful coding assistant." },
    { role: "user", content: "Explain TypeScript generics briefly." }
  ],
  temperature: 0.7,
  max_tokens: 500,
});

console.log(response.choices[0].message.content);

Anthropic-Compatible API

import { DuelClient } from "@duel-agents/sdk";

const duel = new DuelClient({
  apiKey: process.env.DUEL_API_KEY!,
});

const message = await duel.messages.create({
  model: "duel-auto",
  max_tokens: 1024,
  messages: [
    { role: "user", content: "Write a Python function to parse JSON safely." }
  ],
});

console.log(message.content);

Streaming Responses

const stream = await duel.chat.completions.create({
  model: "duel-auto",
  messages: [{ role: "user", content: "Count to 10" }],
  stream: true,
});

for await (const chunk of stream) {
  const content = chunk.choices[0]?.delta?.content;
  if (content) {
    process.stdout.write(content);
  }
}

Error Handling

import { DuelClient } from "@duel-agents/sdk";

const duel = new DuelClient({
  apiKey: process.env.DUEL_API_KEY!,
});

try {
  const response = await duel.chat.completions.create({
    model: "duel-auto",
    messages: [{ role: "user", content: "Hello" }],
  });
} catch (error) {
  if (error.status === 401) {
    console.error("Invalid API key or subscription inactive");
  } else if (error.status === 429) {
    console.error("Rate limit exceeded");
  } else {
    console.error("Request failed:", error.message);
  }
}

IDE Integrations

Claude Code

# Clone repo and install plugin
git clone https://github.com/2aronS/Duel-Agents.git
cd duel-agents
claude plugin install ./integrations/claude-plugin

# Run installer
npx @duel-agents/install claude-code

In Claude Code:

/duel-agents:setup

Follow the guided setup to configure your API key and preferences.

Cursor

The installer copies a skill to .cursor/skills/duel-agents/ and writes DUEL_API_KEY to your project .env.

Manual configuration required:

1. Open Cursor Settings → Models
2. Set Override OpenAI Base URL to: https://duelagents.com/v1
3. Set API Key to your Duel key: duel_yourprefix_yoursecret
4. Select duel-auto as your model

npx @duel-agents/install cursor

Codex CLI

The installer writes OPENAI_BASE_URL and OPENAI_API_KEY to .env:

npx @duel-agents/install codex
# Restart Codex after installation

OpenClaw

Patches ~/.openclaw/openclaw.json with a duel provider and sets the default model:

npx @duel-agents/install openclaw

# Validate configuration
openclaw config validate

Manual configuration (~/.openclaw/openclaw.json):

{
  "providers": {
    "duel": {
      "apiKey": "duel_yourprefix_yoursecret",
      "baseURL": "https://duelagents.com/v1"
    }
  },
  "defaultModel": "duel/duel-auto"
}

A backup is created at openclaw.json.bak before patching.

CLI Commands

Install Command

# Install for specific tool
npx @duel-agents/install <tool>

# Available tools:
# - claude-code
# - cursor
# - codex
# - openclaw
# - all

Doctor Command

Validates your setup and connectivity:

npx @duel-agents/install doctor

Checks:

• API key format validity
• Connectivity to duelagents.com/v1
• Subscription status
• Environment variable configuration

Common Patterns

Multi-Agent System

import { DuelClient } from "@duel-agents/sdk";

const duel = new DuelClient({
  apiKey: process.env.DUEL_API_KEY!,
});

async function coordinatedAgents(task: string) {
  // Planner agent
  const plan = await duel.chat.completions.create({
    model: "duel-auto",
    messages: [
      { role: "system", content: "You are a task planning agent." },
      { role: "user", content: `Create a plan for: ${task}` }
    ],
  });

  const steps = plan.choices[0].message.content;

  // Executor agent
  const execution = await duel.chat.completions.create({
    model: "duel-auto",
    messages: [
      { role: "system", content: "You are a task execution agent." },
      { role: "user", content: `Execute this plan:\n${steps}` }
    ],
  });

  return execution.choices[0].message.content;
}

Cost-Aware Routing

import { DuelClient } from "@duel-agents/sdk";

const duel = new DuelClient({
  apiKey: process.env.DUEL_API_KEY!,
});

async function analyzeCode(code: string, complexity: "simple" | "complex") {
  // Duel automatically routes to cheaper models for simple tasks
  const response = await duel.chat.completions.create({
    model: "duel-auto",
    messages: [
      {
        role: "user",
        content: `Analyze this ${complexity} code:\n\n${code}`
      }
    ],
    // Duel uses prompt complexity to select optimal model
  });

  return response.choices[0].message.content;
}

Use with Existing OpenAI Code

Replace only the client initialization:

// Before:
// import OpenAI from "openai";
// const client = new OpenAI({ apiKey: process.env.OPENAI_API_KEY });

// After:
import { DuelClient } from "@duel-agents/sdk";
const client = new DuelClient({
  apiKey: process.env.DUEL_API_KEY!,
});

// All existing OpenAI code works unchanged
const response = await client.chat.completions.create({
  model: "duel-auto", // or keep your existing model name
  messages: [{ role: "user", content: "Hello" }],
});

Fallback Strategy

import { DuelClient } from "@duel-agents/sdk";

const duel = new DuelClient({
  apiKey: process.env.DUEL_API_KEY!,
});

async function robustCompletion(prompt: string) {
  try {
    // Try Duel routing first (cost-optimized)
    return await duel.chat.completions.create({
      model: "duel-auto",
      messages: [{ role: "user", content: prompt }],
    });
  } catch (error) {
    console.warn("Duel routing failed, using direct fallback");
    // Fallback logic here if needed
    throw error;
  }
}

Troubleshooting

Invalid API Key Format

Symptom: Invalid API key format error

Solution:

• Key must match pattern: duel_ + 8 chars + _ + 32 chars
• Create a new key at https://duelagents.com/dashboard/settings
• Verify no extra whitespace: echo "$DUEL_API_KEY" | wc -c should be 46

401 Unauthorized

Symptom: 401 error when running doctor or making requests

Solution:

• Key may be revoked or subscription inactive
• Check billing status at dashboard
• Generate a new API key
• Ensure key is exported: echo $DUEL_API_KEY

Could Not Reach Duel API

Symptom: Connection errors to duelagents.com/v1

Solution:

• Verify internet connectivity
• Check if duelagents.com is accessible: curl https://duelagents.com/v1/health
• Proxy may be temporarily down; retry after a few minutes
• Check for firewall or VPN restrictions

Cursor Still Uses OpenAI

Symptom: Cursor not routing through Duel

Solution:

1. Open Settings → Models → Override OpenAI Base URL
2. Set to: https://duelagents.com/v1
3. Set API key field to your duel_* key (not OpenAI key)
4. Restart Cursor
5. Select duel-auto or duel/duel-auto as model

OpenClaw Won't Start

Symptom: OpenClaw fails after Duel installation

Solution:

# Validate configuration
openclaw config validate

# Restore from backup if needed
cp ~/.openclaw/openclaw.json.bak ~/.openclaw/openclaw.json

# Reinstall
npx @duel-agents/install openclaw

Skill Copy Failed

Symptom: Cursor skill not found after npm install

Solution:

# Rebuild the package
git clone https://github.com/2aronS/Duel-Agents.git
cd duel-agents
npm install
npm run build

# Reinstall
npx @duel-agents/install cursor

TypeScript Type Errors

Symptom: TypeScript errors with SDK

Solution:

# Ensure latest version
npm install @duel-agents/sdk@latest

# Check TypeScript version (>= 4.5 recommended)
npm list typescript

Model Selection

Available Models

• duel-auto - Automatic routing (recommended)
• Any OpenAI model name (routed through Duel)
• Any Anthropic model name (routed through Duel)

How Auto-Routing Works

Duel analyzes:

1. Prompt complexity
2. Required capabilities (code, reasoning, creative)
3. Token length
4. Historical quality metrics

Then selects the cheapest model that meets the quality threshold for that specific request.

Advanced Configuration

Custom Base URL (Staging)

import { DuelClient } from "@duel-agents/sdk";

const duel = new DuelClient({
  apiKey: process.env.DUEL_API_KEY!,
  baseURL: process.env.DUEL_PROXY_URL || "https://duelagents.com/v1",
});

Timeout Configuration

import { DuelClient } from "@duel-agents/sdk";

const duel = new DuelClient({
  apiKey: process.env.DUEL_API_KEY!,
  timeout: 60000, // 60 seconds
});

Repository Structure

packages/
  core/       @duel-agents/core    - Validation, env handling, connectivity
  cli/        @duel-agents/install - Installer CLI tool
  sdk/        @duel-agents/sdk     - TypeScript API client

integrations/
  claude-plugin/  - Claude Code plugin
  cursor-skill/   - Cursor IDE skill
  openclaw-skill/ - OpenClaw integration

templates/
  cursor-models.override.md - Cursor configuration example
  openclaw.duel.json5       - OpenClaw configuration example

Development

# Clone repository
git clone https://github.com/2aronS/Duel-Agents.git
cd duel-agents

# Install dependencies
npm install

# Build all packages
npm run build

# Run tests
npm test

# Run installer locally
npm run cli -- install doctor

License

MIT License - see repository for full text.