Top free AI agents for software development
Greg Foster
Graphite software engineer
Table of contents
- What are AI agents in software development?
- Free AI agent frameworks and tools (2025)
- Graphite: Graphite Agent & Chat
- Summary comparison
- Frequently asked questions
What are AI agents in software development?
AI agents are autonomous, intelligent tools—often built on large language models (LLMs)—that go beyond responding to prompts. They can perform tasks like writing, reviewing, testing, debugging, and coordinating workflows to boost developer productivity.
Free AI agent frameworks and tools (2025)
Here's an updated rundown of prominent free or open-source AI agents for developers:
Google Gemini CLI
An open-source CLI agent powered by Gemini 2.5 Pro. Seamlessly integrates coding, research, content creation, and even image/video generation into your terminal, with a generous free tier offering up to 60 model requests/minute and 1,000 daily requests. It supports Model Context Protocol (MCP) and Google search integration.
Google Jules (Beta)
An asynchronous coding agent launched at Google I/O 2025. It processes coding tasks in the background while developers continue working. Currently free in beta.
Open-weight models by Open AI
OpenAI released "open weight" models—GPT‑OSS‑120B and GPT‑OSS‑20B‑two—which are free to download and customize for agent workflows, offering high reasoning performance.
Open-source agent frameworks
- AutoAgent: Enables creating and deploying LLM agents using only natural language—no coding required. Excels on GAIA benchmarks.
- Autogen Studio: Microsoft's no-code interface for building, debugging, and evaluating multi-agent workflows. Open-source and visual via drag-and-drop.
- AutoGPT: Open-source, autonomous agent that decomposes goals into subtasks and executes using tools. Popular but with noted limitations (e.g., looping, hallucinations).
Code editing support: Zed Editor
A free, open-source ( AGPL, GPL, Apache) editor featuring AI assistance, Model Context Protocol, Git integration, and an agent panel. The free tier has monthly generative limits.
Other notable agents
- CodeGPT: AI agent platform offering code review, automated testing, refactoring, codebase navigation, and agent customization. Free tier available.
- Zencoder and Qodo: Qodo, formerly Codium, provides intelligent multi-agent code review, testing, generation across IDE, terminal, and CI; Zencoder analyzes whole codebases with advanced repo "grokking."
Graphite: Graphite Agent & Chat
Launched March 2025, Graphite Agent is an AI code review assistant that integrates into pull requests. It delivers contextual feedback on bugs, logic, style, security, and more—with customizable rules and minimal noise. Trusted by teams like Snowflake, Duolingo, and Ramp.
Graphite Chat
Released in beta August 2025 (official launch noted Aug 19, 2025), Chat allows you to ask questions, get instant fixes, apply changes, and even merge—all within the pull request. It understands diffs, codebase context, test coverage, style patterns, and CI statuses. Currently free and unlimited during the beta period.
Summary comparison
| Tool/Framework | Type | Free/Open-source | Standout capability |
|---|---|---|---|
| Google Gemini CLI | Terminal agent | Free | CLI-based coding, research, media, MCP, 1M token context |
| Google Jules (Beta) | Async coding agent | Free (beta) | Background task resolution |
| Open-weight models | LLM foundation | Free | Customizable base for agent workflows |
| AutoAgent | Zero-code agent tool | Open-source & free | Natural-language agent creation |
| Autogen Studio | No-code multi-agent UI | Open-source & free | Visual agent workflow building |
| AutoGPT | Autonomous agent | Open-source | Goal decomposition & execution |
| Zed Editor | Agentic editor | Free (with limits) | AI in-editor, MCP, Git, agent panel |
| CodeGPT | Agent platform | Free tier | PR analysis, refactoring, codebase navigation |
| Qodo / Zencoder | Code review agents | Free tier | Multi-agent testing and code quality |
| Graphite Graphite Agent | PR agent | Free tier | Context-aware code review with minimal noise |
| Graphite Chat | PR agent | Free (beta) | Conversational interaction, fixes, merge in PR |
Frequently asked questions
How do I get started with Graphite Chat?
Just open a pull request in Graphite-enabled workflow, click "Ask Graphite" or press Command + ; to start chatting, get suggestions, commit, and merge—all without context switching.
Are Graphite Graphite Agent or Chat always free?
Graphite Agent currently offers a free tier. Graphite Chat is free and unlimited during its beta, as of its August 2025 launch.
What limitations exist in the free tiers?
- Gemini CLI limits: 60 requests/minute, 1,000/day.
- Zed Editor restricts monthly AI query volume.
- Other platforms may impose rate limits or usage caps even in free plans—check vendor-specific docs.
I'm non-technical—what's the easiest way to build an AI agent?
Try AutoAgent (natural-language agent creation, no code) or Autogen Studio (visual drag-and-drop multi-agent construction). Both require no coding.
Which tool offers the best code review experience?
For PR-integrated review: Graphite Graphite Agent provides context-aware feedback, while Graphite Chat enables conversational interaction, fixes, and merging directly inside PR. For other workflows: Qodo, CodeGPT, or Zencoder also offer strong review automation.