AI coding agents
AI coding agents compared
Quick picks
- Best overall in the terminal: Claude Code or OpenAI Codex
- Best free tier: Gemini CLI or GitHub Copilot
- Best open source, any model: OpenCode or Cline
- Best inside an editor: Cursor or GitHub Copilot
- Best for handing off tickets: Devin or OpenAI Codex
- Best for specs before code: Kiro or Augment Code
Terminal agents
Run in your shell, read the repo, edit files and run commands. Pair with any editor.
| Agent | Best for | Free plan | Paid from | Models |
|---|---|---|---|---|
| Claude Code Anthropic's agent that reads your codebase, edits files and runs commands. Terminal, IDE extension, cloud | A general-purpose agent bundled with a Claude subscription | None (not in the Free Claude plan) | $20/mo Pro ($17/mo billed annually) | Claude models only (Opus, Sonnet, Haiku) |
| OpenAI CodexCLI: Apache-2.0 OpenAI's coding agent: CLI, IDE extension, desktop app and cloud tasks. Terminal, IDE extension, desktop app, cloud | ChatGPT subscribers who want one agent for local and cloud work | Included in ChatGPT Free for quick coding tasks | $8/mo Go (light use); $20/mo Plus adds web, CLI and IDE | OpenAI models on ChatGPT plans; or any model your OpenAI API key can use |
| Gemini CLIApache-2.0 Google's open-source terminal agent running on Gemini models. Terminal | The most generous free tier, with a 1M-token context | Personal Google account: 60 requests/min, 1,000 requests/day | Gemini API key or Gemini Code Assist license (pay as you go) | Gemini models only (Flash and Pro mix on the free tier) |
| OpenCodeopen source Open-source, provider-agnostic coding agent with a terminal UI. Terminal, desktop app, IDE extension | Reusing a model subscription or API keys you already pay for | Free tool; includes some free models (limits not stated) | Free (pay your model provider) | 75+ providers and local models; sign in with GitHub Copilot or ChatGPT Plus/Pro |
| AiderApache-2.0 Open-source pair programmer that edits your repo and commits each change to git. Terminal | Git-centric terminal workflows with any model, including local ones | Free; no paid plans | Free (pay your model provider) | Any LLM, including local models; bring your own API key |
| Amp Coding agent that runs in sandboxed cloud environments (orbs) or locally via its CLI. Terminal, cloud | Agents that run unattended in the cloud, reviewed from any device | Hobby: all features; bring your own keys or ChatGPT/Claude subscription; orbs pay as you go | $20/mo Individual (45,000 orb minutes) | Bring your own keys or link ChatGPT/Claude; Amp credits for Claude and GPT |
| Warp A modern terminal with a built-in agent and Oz cloud agents. Terminal app, cloud | An agentic terminal you can share with a team | Terminal and agent with your own AI keys; limited cloud agents | $20/mo Build ($18/mo annual), includes $20 of usage | OpenAI, Anthropic, Google, xAI and open models; bring your own key |
- Claude Code: Shares one usage pool with Claude chat: 5-hour windows plus weekly limits. (source)
- OpenAI Codex: Plan usage is capped per 5 hours with weekly limits; the API-key route has no cloud features. (source)
- Gemini CLI: Free tier stops at 1,000 requests a day and is limited to Gemini models. (source)
- OpenCode: You bring and pay for the models (API keys, subscriptions or the paid Zen service). (source)
- Aider: No hosted service or bundled credits: you supply and pay for the model. (source)
- Amp: Cloud environment time is metered beyond what the plan includes. (source)
- Warp: Free plan includes no agent usage: bring your own key or upgrade. (source)
AI IDEs and editors
An editor built around the agent: diffs, review and tab completions in one window.
| Agent | Best for | Free plan | Paid from | Models |
|---|---|---|---|---|
| Cursor AI-first code editor with a built-in agent, cloud agents and AI code review. IDE | An agent inside a VS Code-style editor | Limited agent and chat requests | $8/mo Plus (Grok models only); $30/mo Premium adds cloud agents and other models | Grok models included; Claude, GPT and others at API list price, billed separately |
| Windsurf (Devin Desktop) AI IDE, now Devin Desktop, for running local and cloud agents in one place. IDE, JetBrains plugin | One editor to manage several agents (Devin, Codex, Claude) | Light agent quota, limited models, unlimited Tab completions | $20/mo Pro | OpenAI, Claude, Gemini and open models, plus Cognition's SWE models |
| Kiro AWS's agentic IDE built around specs: requirements and a plan before code. IDE, Terminal, web | Teams that want specs before code, especially on AWS | 50 credits a month (Claude Sonnet and open-weight models) | $20/mo Pro (1,000 credits) | Auto mode, Claude, GPT and open-weight models |
| ZedGPL-3.0 Fast open-source editor with an agent panel; runs Claude Code, Codex and other agents via ACP. Editor | A fast native editor where you plug in your own keys or agents | Free forever with your own API keys or external agents | $10/mo Pro | Bring your own key (Anthropic, OpenAI, Google, Ollama, OpenRouter) or Zed-hosted models |
- Cursor: Third-party models (Claude, GPT) are billed on top of every plan. (source)
- Windsurf (Devin Desktop): Quotas refresh daily and weekly; extra usage is billed at API prices. (source)
- Kiro: Credits don't roll over; extra credits cost $0.04 each. (source)
- Zed: Pro includes only $5 of tokens a month; more is API price plus 10%. (source)
Editor extensions
Add an agent to the editor you already use (VS Code, JetBrains and others).
| Agent | Best for | Free plan | Paid from | Models |
|---|---|---|---|---|
| GitHub Copilot Agent mode in VS Code, JetBrains, Visual Studio and Xcode, plus a cloud agent and CLI. Editor extension, Terminal, cloud | Teams already on GitHub | 2,000 completions a month, Haiku 4.5 and GPT-5 mini, Copilot CLI | $10/mo Pro ($15 of AI credits) | Several models including Claude and GPT; premium models (Opus) from Pro+ |
| ClineApache-2.0 Open-source agent with Plan and Act modes that asks before each step. Editor extension, Terminal, desktop app | Full model choice and step-by-step control | Free for individuals; you pay only for inference | Free (pay your model provider) | Bring your own key: Anthropic, OpenAI, Google, Bedrock, Ollama, any OpenAI-compatible API |
| Kilo CodeMIT Open-source agent for VS Code, JetBrains and the CLI, with a model gateway. Editor extension, Terminal, cloud | One agent across editors, with free models and no markup | Free; Auto Free routes to free models, or use your own keys or local models | Free (pay your model provider); Kilo Pass $19/mo | 500+ models across 60+ providers at provider rates; local models |
Cloud agents
Hand off a task; the agent works in a cloud sandbox and opens a pull request.
| Agent | Best for | Free plan | Paid from | Models |
|---|---|---|---|---|
| Devin Cognition's autonomous software engineer that works in the cloud and opens PRs. Cloud agent, desktop, CLI | Delegating well-scoped tickets that come back as pull requests | Light agent quota with limited models | $20/mo Pro (includes Devin Cloud) | OpenAI, Claude, Gemini and open models, plus Cognition's SWE models |
| Augment Code Agents with a Context Engine that indexes large codebases; cloud agents and a CLI. Cloud agents, Terminal | Teams working in large codebases | None | $20/mo Standard (flat, up to 50 seats, $20 of usage) | Major providers' models at API list price |
Head-to-head comparisons
- Claude Code vs OpenAI Codex
- Claude Code vs Cursor
- Claude Code vs GitHub Copilot
- Claude Code vs Gemini CLI
- Cursor vs GitHub Copilot
- Cursor vs Windsurf (Devin Desktop)
- Claude Code vs OpenCode
- Cursor vs Kiro
- Claude Code vs Cline
- Cline vs Cursor
- Aider vs Claude Code
- Gemini CLI vs OpenAI Codex
- Cursor vs OpenAI Codex
- GitHub Copilot vs OpenAI Codex
- Cursor vs Devin
- Amp vs Claude Code
- Claude Code vs Windsurf (Devin Desktop)
- Cursor vs Zed
More: vibe coding tools (prompt-to-app builders) · all AI coding tools · free LLM API keys · AI model API pricing.
FAQ
What is the best AI coding agent?+
For most developers: Claude Code or OpenAI Codex in the terminal, or Cursor if you want the agent inside your editor. Gemini CLI has the most generous free tier (1,000 requests a day). For open source with any model, use OpenCode, Cline or Aider.
What is an AI coding agent?+
A tool that takes a task in plain language, reads your codebase, edits files, runs commands and tests, and iterates until the task is done. Unlike autocomplete, it works across many files and steps; you review the diff.
Are there free AI coding agents?+
Yes. Gemini CLI is free with a Google account (60 requests a minute, 1,000 a day). GitHub Copilot Free and Codex in ChatGPT Free cover light use. OpenCode, Cline, Kilo Code and Aider are free and open source: you pay only for the model, or use a free LLM API key.
Claude Code or Codex?+
Both are terminal-first agents with IDE extensions and cloud tasks. Claude Code runs only Claude models and needs a paid Claude plan ($20/mo Pro); Codex runs OpenAI models and is included even in ChatGPT Free for light use. Pick the one whose subscription you already pay for.
Can I use my own API key?+
OpenCode, Cline, Kilo Code, Aider, Zed and Warp take your own keys for most providers; Codex works with an OpenAI API key; Gemini CLI with a Gemini API key. Claude Code, Cursor and Copilot bill through their own plans.