AI Coding Agents Overview

MegaLLM supports all major AI coding agents. This unified guide covers configuration for Claude Code, Codex/Windsurf, OpenCode, Kilocode, RooCode, and Cline.

Available Agents

Claude Code

CLI + Editor integration with JSON config

Codex/Windsurf

CLI + Editor with TOML config

OpenCode

CLI + Editor with auto-model fetching

Kilocode

VSCode extension with inline chat (CLI coming soon)

RooCode

Standalone app with visual interface

Cline

VSCode extension with autonomous tasks (CLI coming soon)

Quick Comparison

Agent	Interfaces	Config Format	Config Level	Best For
Claude Code	CLI + VSCode	JSON	System + Project	Terminal workflows, VSCode integration
Codex/Windsurf	CLI + Editor	TOML	System only	Advanced users, Cascade AI
OpenCode	CLI + Editor	JSON	System + Project	Multi-model switching, flexibility
Kilocode	VSCode (CLI soon)	VSCode settings	User + Workspace	Inline chat, code completion
RooCode	Standalone app	JSON	App-level	Visual UI, standalone workflow
Cline	VSCode (CLI soon)	VSCode settings	User + Workspace	Autonomous tasks, terminal ops

Agent Types

CLI-First Agents (with Editor Support)

Claude Code

CLI-first design
VSCode extension available
JSON configuration
System & project-level
Statusline support

Codex/Windsurf

CLI-first design
Editor integrations
TOML configuration
Cascade AI (Windsurf)
Supercomplete features

OpenCode

CLI-first design
Editor plugins available
JSON configuration
Auto-fetch models
Multi-provider support

When to use CLI-first agents:

Terminal-based workflows
CI/CD integration
Server environments
Scripting and automation
Also work great in editors with extensions

Editor-Only Agents (CLI Coming Soon)

Kilocode

VSCode extension (primary)
CLI under maintenance
Inline chat interface
Code completion
File tree integration

RooCode

Standalone app
Visual interface
Multi-project support
Code review features

Cline

VSCode extension (primary)
CLI under maintenance
Autonomous task execution
Terminal integration
Git workflow support

CLI Support for Kilocode & Cline: CLI versions are currently under maintenance and will be available soon. Use the VSCode extensions in the meantime.

When to use editor-focused agents:

Pure visual editing workflows
Inline suggestions and completions
Multi-file refactoring
Code review workflows
IDE-native experience

Getting Started

Choose Your Agent

Select a CLI agent for terminal workflows or a GUI agent for visual editing

Get Your API Key

Configure Your Agent

Follow the specific configuration guide for your chosen agent (linked below)

Start Coding

Launch your agent and start using AI-powered coding assistance

Configuration Guides

CLI-First Agents (also work in editors)

Claude Code - CLI + VSCode

Works as: CLI tool + VSCode extensionConfiguration files:

System: ~/.claude/settings.json
Project: ./.claude/settings.json
Local: ./.claude/settings.local.json

Quick setup:

{
  "env": {
    "ANTHROPIC_BASE_URL": "https://ai.megallm.io",
    "ANTHROPIC_API_KEY": "sk-mega-your-api-key-here"
  }
}

Full Claude Code Configuration Guide →

Codex/Windsurf - CLI + Editor

Works as: CLI tool + Editor integrations (Windsurf is enhanced variant)Configuration file:

System: ~/.codex/config.toml (only)

Quick setup:

model_provider = "megallm"
model = "gpt-5"

[model_providers.megallm]
name = "OpenAI using Chat Completions"
base_url = "https://ai.megallm.io/v1"
env_key = "MEGALLM_API_KEY"

[tools]
web_search = true
file_browser = true

Full Codex/Windsurf Configuration Guide →

OpenCode - CLI + Editor Plugins

Works as: CLI tool + Editor plugins (VSCode, Vim, etc.)Configuration files:

System: ~/.config/opencode/opencode.json
Project: ./.opencode/opencode.json

Quick setup:

{
  "providers": [
    {
      "id": "megallm",
      "name": "MegaLLM",
      "type": "openai",
      "baseURL": "https://ai.megallm.io/v1",
      "apiKey": "sk-mega-your-api-key-here"
    }
  ],
  "defaultProvider": "megallm"
}

Full OpenCode Configuration Guide →

Editor-Only Agents

Kilocode - VSCode Extension

Configuration location:

User Settings (global): VSCode Settings UI or settings.json
Workspace Settings (project): .vscode/settings.json

Quick setup (settings.json):

{
  "kilocode.apiProvider": "custom",
  "kilocode.customProvider": {
    "name": "MegaLLM",
    "baseURL": "https://ai.megallm.io/v1",
    "apiKey": "${env:MEGALLM_API_KEY}"
  },
  "kilocode.defaultModel": "gpt-5"
}

Environment variable:

export MEGALLM_API_KEY="sk-mega-your-api-key-here"

Full Kilocode Configuration Guide →

RooCode - Standalone App

Configuration location:

Windows: %APPDATA%\RooCode\config.json
macOS: ~/Library/Application Support/RooCode/config.json
Linux: ~/.config/roocode/config.json

Quick setup:

{
  "provider": "openai-compatible",
  "api": {
    "baseURL": "https://ai.megallm.io/v1",
    "apiKey": "sk-mega-your-api-key-here",
    "model": "gpt-5"
  },
  "features": {
    "codeCompletion": true,
    "chatInterface": true,
    "codeReview": true,
    "terminalIntegration": false
  }
}

Full RooCode Configuration Guide →

Cline - VSCode Extension with Autonomy

Configuration location:

User Settings (global): VSCode Settings UI or settings.json
Workspace Settings (project): .vscode/settings.json

Quick setup for GPT models (OpenAI format):

{
  "cline.apiProvider": "openai",
  "cline.openai": {
    "apiKey": "${env:MEGALLM_API_KEY}",
    "baseURL": "https://ai.megallm.io/v1"
  },
  "cline.defaultModel": "gpt-5"
}

Quick setup for Claude models (Anthropic format):

{
  "cline.apiProvider": "anthropic",
  "cline.anthropic": {
    "apiKey": "${env:MEGALLM_API_KEY}",
    "baseURL": "https://ai.megallm.io"
  },
  "cline.defaultModel": "claude-sonnet-4"
}

Environment variable:

export MEGALLM_API_KEY="sk-mega-your-api-key-here"

Full Cline Configuration Guide →

Model Selection

All agents support the same models through MegaLLM:

GPT Models

gpt-5 - Latest GPT model (recommended)
gpt-4 - GPT-4
gpt-4o - GPT-4 Optimized
gpt-4o-mini - Fast, cost-effective

Claude Models

claude-opus-4-1-20250805 - Most capable
claude-sonnet-4 - Balanced (recommended)
claude-haiku-4 - Fast, efficient

Gemini Models

gemini-2.5-pro - Latest Gemini
gemini-2.0-flash - Fast responses

See Full Model Catalog →

Environment Variables

Most agents support environment variables for API keys:

# For CLI agents and some GUI agents
export MEGALLM_API_KEY="sk-mega-your-api-key-here"

# For Claude Code specifically
export ANTHROPIC_BASE_URL="https://ai.megallm.io"
export ANTHROPIC_API_KEY="sk-mega-your-api-key-here"

Add to your shell configuration:

Bash: ~/.bashrc
Zsh: ~/.zshrc
Fish: ~/.config/fish/config.fish

Common Configuration Patterns

Pattern 1: System-Level for Personal Use

Best for: Personal projects, single user

Claude Code
Kilocode
RooCode

# System configuration
~/.claude/settings.json

# Environment variables
export ANTHROPIC_BASE_URL="https://ai.megallm.io"
export ANTHROPIC_API_KEY="sk-mega-your-key"

# VSCode User Settings
# File > Preferences > Settings > Search "kilocode"

# Environment variable
export MEGALLM_API_KEY="sk-mega-your-key"

# App configuration
~/.config/roocode/config.json

# Store API key in config or use env var

Pattern 2: Project-Level for Teams

Best for: Team projects, shared configuration

Claude Code
Kilocode
OpenCode

# Shared config (committed)
.claude/settings.json
{
  "env": {
    "ANTHROPIC_BASE_URL": "https://ai.megallm.io"
  }
}

# Personal key (not committed)
.claude/settings.local.json
{
  "env": {
    "ANTHROPIC_API_KEY": "your-personal-key"
  }
}

# .gitignore
.claude/settings.local.json

# Workspace settings (committed)
.vscode/settings.json
{
  "kilocode.apiProvider": "custom",
  "kilocode.customProvider": {
    "name": "MegaLLM",
    "baseURL": "https://ai.megallm.io/v1",
    "apiKey": "${env:MEGALLM_API_KEY}"
  }
}

# Team members set their own env var
export MEGALLM_API_KEY="personal-key"

# Project config (committed)
.opencode/opencode.json
{
  "providers": [{
    "baseURL": "https://ai.megallm.io/v1"
  }]
}

# Personal key via env var
export MEGALLM_API_KEY="personal-key"

Pattern 3: Multi-Model Configuration

Best for: Using different models for different tasks

OpenCode
RooCode

{
  "providers": [
    {
      "id": "megallm-gpt",
      "type": "openai",
      "baseURL": "https://ai.megallm.io/v1",
      "models": ["gpt-5", "gpt-4o"]
    },
    {
      "id": "megallm-claude",
      "type": "anthropic",
      "baseURL": "https://ai.megallm.io",
      "models": ["claude-sonnet-4", "claude-opus-4"]
    }
  ]
}

{
  "providers": [
    {
      "name": "GPT for Chat",
      "model": "gpt-5",
      "useFor": ["chat", "completion"]
    },
    {
      "name": "Claude for Review",
      "model": "claude-sonnet-4",
      "useFor": ["review", "analysis"]
    }
  ]
}

Troubleshooting

API Key Not Working

Verify your API key:

# Check it starts with sk-mega-
echo $MEGALLM_API_KEY

# Test the API directly
curl -H "Authorization: Bearer $MEGALLM_API_KEY" \
     https://ai.megallm.io/v1/models

Common issues:

Missing sk-mega- prefix
Extra spaces or quotes
Wrong environment variable name
Shell config not reloaded (run source ~/.bashrc)

Wrong API Endpoint

Check your base URL:For OpenAI-compatible format (GPT, Gemini):

https://ai.megallm.io/v1  <Icon icon="check" /> (with /v1)

For Anthropic format (Claude):

https://ai.megallm.io  <Icon icon="check" /> (no /v1)

Agent-specific endpoints:

Claude Code: https://ai.megallm.io (no /v1)
Codex/Windsurf: https://ai.megallm.io/v1
OpenCode: https://ai.megallm.io/v1
Kilocode: https://ai.megallm.io/v1
RooCode: https://ai.megallm.io/v1
Cline: https://ai.megallm.io (Anthropic) or https://ai.megallm.io/v1 (OpenAI)

Model Not Found

Verify model name spelling:Check Models Catalog for exact model names:

# Common mistakes:
"gpt5"           <Icon icon="xmark" />  # Missing dash
"gpt-5"          <Icon icon="check" />

"claude-sonnet"  <Icon icon="xmark" />  # Missing version
"claude-sonnet-4" <Icon icon="check" />

"gemini-pro"     <Icon icon="xmark" />  # Wrong version
"gemini-2.5-pro" <Icon icon="check" />

Configuration Not Loading

Check file locations:

# CLI agents
ls -la ~/.claude/settings.json      # Claude Code
ls -la ~/.codex/config.toml         # Codex
ls -la ~/.config/opencode/           # OpenCode

# Project configs
ls -la .claude/settings.json         # Claude Code
ls -la .opencode/opencode.json       # OpenCode
ls -la .vscode/settings.json         # VSCode extensions

# Validate JSON/TOML syntax
jq . ~/.claude/settings.json         # Test JSON
cat ~/.codex/config.toml | grep -    # Test TOML

Check permissions:

chmod 644 ~/.claude/settings.json
chmod 644 ~/.codex/config.toml

Environment Variables Not Set

Reload your shell config:

# Bash
source ~/.bashrc

# Zsh
source ~/.zshrc

# Fish
source ~/.config/fish/config.fish

# Verify
echo $MEGALLM_API_KEY
echo $ANTHROPIC_BASE_URL

Check where it’s defined:

# Search all shell configs
grep -r "MEGALLM_API_KEY" ~/.*rc ~/.config/

Feature Comparison

Interfaces & Usage

Agent	CLI Available	Editor/GUI	Chat Interface
Claude Code	Primary	VSCode ext	CLI + GUI
Codex/Windsurf	Primary	Editor	CLI + GUI
OpenCode	Primary	Plugins	CLI + GUI
Kilocode	Coming soon	VSCode only	GUI
RooCode		Standalone	GUI
Cline	Coming soon	VSCode only	GUI

Integrations

Agent	Terminal Access	Git Integration	Code Review
Claude Code	Native CLI	Native	In editor
Codex/Windsurf	Native CLI	Native	In editor
OpenCode	Native CLI	Native	In editor
Kilocode	Via VSCode	VSCode
RooCode	Built-in	Built-in
Cline	VSCode term	VSCode

Configuration Flexibility

Agent	Project Config	Env Vars	Team Sharing
Claude Code
Codex/Windsurf			Limited
OpenCode
Kilocode
RooCode	Import	Limited	Export
Cline

Best Practices

Use Environment Variables

Store API keys in environment variables, never commit them to version control

Project-Level for Teams

Use project-level config for shared settings, local files for personal keys

Choose Right Agent

CLI for automation/CI/CD, GUI for interactive coding and visual workflows

Test Configuration

Verify API connection with curl before configuring agents

Keep Keys Secure

Add sensitive files to .gitignore, use different keys for dev/prod

Regular Updates

Keep agents updated for latest features, security patches, and bug fixes

Next Steps

Claude Code

CLI with JSON config

Codex/Windsurf

CLI with TOML config

OpenCode

CLI with auto-fetch

Kilocode

VSCode extension

RooCode

Standalone app

Cline

VSCode + autonomy

Models Catalog

Browse all available models

API Reference

Direct API integration

​Available Agents

Claude Code

Codex/Windsurf

OpenCode

Kilocode

RooCode

Cline

​Quick Comparison

​Agent Types

​CLI-First Agents (with Editor Support)

Claude Code

Codex/Windsurf

OpenCode

​Editor-Only Agents (CLI Coming Soon)

Kilocode

RooCode

Cline

​Getting Started

​Configuration Guides

​CLI-First Agents (also work in editors)

​Editor-Only Agents

​Model Selection

​GPT Models

​Claude Models

​Gemini Models

​Environment Variables

​Common Configuration Patterns

​Pattern 1: System-Level for Personal Use

​Pattern 2: Project-Level for Teams

​Pattern 3: Multi-Model Configuration

​Troubleshooting

​Feature Comparison

​Interfaces & Usage

​Integrations

​Configuration Flexibility

​Best Practices

Use Environment Variables

Project-Level for Teams

Choose Right Agent

Test Configuration

Keep Keys Secure

Regular Updates

​Next Steps

Claude Code

Codex/Windsurf

OpenCode

Kilocode

RooCode

Cline

Models Catalog

API Reference

Available Agents

Quick Comparison

Agent Types

CLI-First Agents (with Editor Support)

Editor-Only Agents (CLI Coming Soon)

Getting Started

Configuration Guides

CLI-First Agents (also work in editors)

Editor-Only Agents

Model Selection

GPT Models

Claude Models

Gemini Models

Environment Variables

Common Configuration Patterns

Pattern 1: System-Level for Personal Use

Pattern 2: Project-Level for Teams

Pattern 3: Multi-Model Configuration

Troubleshooting

Feature Comparison

Interfaces & Usage

Integrations

Configuration Flexibility

Best Practices

Next Steps