AI coding agents & harnesses

StackBlitz

Browser-based AI app builder powered by WebContainers that generates, runs, and iterates on full-stack applications entirely in the browser.

Default model: Claude Sonnet 4.6

vendor managed · vendor cloud

Free: Free · Premium: $20/mo · Team: $30/mo · Business: $100/mo · … — Freemium; Pro at $20/mo

Lovable

AI-powered full-stack app builder that converts natural language into production-ready applications with Supabase backend integration and GitHub sync.

Default model: Claude Sonnet 4.6

vendor managed · vendor cloud

Free: Free · Pro: $25/mo · Business: $50/mo · Teams: $30/mo · … — Freemium; Starter at $20/mo

Replit

Cloud-based AI agent that builds full applications from natural language prompts within Replit's browser-based IDE, with instant deployment included.

Default model: Claude Sonnet 4.6

vendor managed · vendor cloud

Starter: Free · Core: $25/mo · Pro: $100/mo · Enterprise — Included with Replit Core (~$25/mo)

Vercel

AI-powered UI generation tool that creates React/Next.js components and full-page designs from natural language prompts, with Shadcn UI and Tailwind CSS integration.

Default model: GPT-4o (2024-11-20)

vendor managed · vendor cloud

Free: Free · Premium: $20/mo · Team: $30/mo · Business: $100/mo · … — Freemium; Pro at $20/mo

Augment

Enterprise AI coding assistant with agentic capabilities, emphasizing security, codebase understanding at scale, and team-oriented features for large engineering organizations.

mixed · hybrid

Indie: $20/mo · Standard: $60/mo · Max: $200/mo · Enterprise — Enterprise pricing (contact sales)

Cline (open source community)

Open-source VS Code extension that gives Claude or other LLMs autonomous access to the terminal, filesystem, and browser to complete complex coding tasks.

Default model: Claude Sonnet 4.6

user owned · hybrid

Free: Free — Free (user pays LLM API costs)

Continue.dev

Open-source IDE extension for VS Code and JetBrains that provides customizable AI coding assistance including chat, autocomplete, and agentic edit capabilities.

user owned · hybrid

Free / Open Source: Free — Free (open source); Enterprise plan available

Anysphere

AI-first code editor (fork of VS Code) with agentic capabilities including multi-file edits, codebase-aware completions, and an agent mode for autonomous task execution.

Default model: Claude Sonnet 4.6

mixed · hybrid

Hobby: Free · Pro: $20/mo · Pro+: $60/mo · Ultra: $200/mo · … — Freemium; Pro at $20/mo

Google

AI coding assistant powered by Gemini, integrated into VS Code and JetBrains IDEs, offering code completion, chat, and agentic code transformation capabilities.

Default model: Gemini 2.5 Pro

mixed · hybrid

Individual: Free · Standard: $19/mo · Enterprise: $45/mo — Free for individuals; Enterprise pricing for teams

GitHub (Microsoft)

AI pair programmer from GitHub with inline code completions, chat, and autonomous multi-step coding agent across VS Code, JetBrains, Neovim, and web. Supports multi-model selection including Claude, GPT, and Gemini.

Default model: GPT-4o (2024-11-20)

mixed · hybrid

Free: Free · Pro: $10/mo · Pro+: $39/mo · Business: $19/mo · …

JetBrains

Native AI assistant integrated into all JetBrains IDEs with context-aware code generation, Junie autonomous agent, and AI credits system. Supports Claude and GPT models with local model option.

mixed · hybrid

AI Free: Free · AI Pro: $8/mo · AI Ultimate: $30/mo · AI Enterprise

Kilo

VS Code extension forked from Cline, offering autonomous coding agent capabilities with a focus on reliability and team-friendly features.

Default model: Claude Sonnet 4.6

user owned · local

Free (open source)

Roo (open source fork of Cline)

VS Code extension and harness framework forked from Cline with enhanced autonomous coding capabilities and additional agent modes.

Default model: Claude Sonnet 4.6

mixed · hybrid

Free (user pays LLM API costs)

Sourcegraph

AI coding assistant with deep codebase search integration, capable of understanding and generating code across entire large-scale repositories using Sourcegraph's search infrastructure.

Default model: Claude Sonnet 4.6

mixed · hybrid

Free: Free · Pro: $9/mo · Enterprise Starter: $19/mo · Enterprise: $59/mo — Free tier; Pro at $9/mo; Enterprise pricing

Tabnine

AI code completion and chat assistant that runs locally or in the cloud, with a focus on enterprise privacy, security compliance, and learning from private codebases.

mixed · hybrid

Code Assistant: $59/mo · Agentic Platform — Starter free; Pro at $12/mo; Enterprise pricing

Codeium

Agentic IDE with a 'Cascade' agent that maintains awareness of the full development flow and can autonomously plan and execute multi-step coding tasks.

Default model: Claude Sonnet 4.6

mixed · hybrid

Free: Free · Pro: $20/mo · Max: $200/mo · Teams: $40/mo · … — Freemium; Pro at $15/mo

Zed Industries

High-performance collaborative code editor with native AI agent integration, built in Rust for speed and designed for human-AI collaboration workflows.

Default model: Claude Sonnet 4.6

user owned · local

Free: Free · Pro: $10/mo · Enterprise — Free; Pro tier for advanced AI features

Paul Gauthier (independent)

Open-source CLI tool for AI-driven code editing via natural language, with deep Git integration that automatically commits changes with descriptive messages.

Default model: Claude Sonnet 4.6

user owned · local

Free / Open Source: Free — Free (user pays LLM API costs)

Sourcegraph (separate product)

AI coding agent terminal tool designed for autonomous multi-step task execution across codebases, positioned as a next-generation CLI harness.

Default model: Claude Opus 4.7

mixed · local

Free beta

Anthropic

Autonomous coding agent that runs in the terminal, capable of editing files, running commands, and managing the entire development workflow with minimal human intervention.

Default model: Claude Sonnet 4.6

user owned · local

Pro: $20/mo · Max 5x: $100/mo · Max 20x: $200/mo · Team: $25/mo · … — Included with Claude Pro/Max subscription (~$20-100/mo); API usage billed separately

Block (Square parent company)

Open-source autonomous AI coding agent by Block that runs locally, with extensible tool support for filesystem, shell, and external APIs.

user owned · local

Free (user pays LLM API costs)

OpenAI

Open-source command-line coding agent released April 2025 that runs code, browses files, and executes multi-step tasks in a sandboxed environment using OpenAI models.

Default model: GPT-5.4

mixed · hybrid

Free: Free · ChatGPT Go: $8/mo · ChatGPT Plus: $20/mo · ChatGPT Pro: $200/mo · … — Free (user pays OpenAI API costs)

Mario Zechner

Open-source AI agent toolkit with a minimal 4-tool core (Read, Write, Edit, Bash) that self-extends at runtime. Includes coding agent CLI, unified LLM API, TUI/web UI, and Slack bot.

user owned · local

Free and open source; bring your own LLM API keys

Plandex

Open-source CLI coding agent designed for large-scale, multi-step tasks with explicit planning stages and reliable multi-file changes across large codebases.

user owned · hybrid

Free (self-hosted); Cloud plan available

Warp

AI-native terminal and coding environment with built-in agent capabilities for running commands, debugging, and completing coding tasks via natural language.

user owned · local

Free: Free · Build: $20/mo · Business: $50/mo · Enterprise — Freemium; Pro at $15/mo

Amazon Web Services

AI coding assistant and agent deeply integrated with AWS services, capable of autonomous feature implementation, test generation, and security scanning.

vendor managed · vendor cloud

Free: Free · Pro: $19/mo — Free tier; Pro at $19/user/mo

Cognition Labs

Cloud-based autonomous AI software engineer that works in a sandboxed environment with a browser, terminal, and code editor to complete full engineering tasks.

vendor managed · vendor cloud

Starter: Free · Pro: $30/mo · Core: $20/mo · Team: $500/mo · … — Subscription starting at $500/mo

GitHub (Microsoft)

Cloud-based development environment that uses AI to go from GitHub issue to working implementation, handling planning, code changes, and test execution.

vendor managed · vendor cloud

Included with GitHub Copilot subscription (~$10-19/mo)

Google DeepMind

Experimental async AI coding agent from Google that handles GitHub issues autonomously in the background, producing pull requests without blocking developers.

Default model: Gemini 3 Pro

vendor managed · vendor cloud

Free: Free · AI Pro: $19.99/mo · AI Ultra: $124.99/mo — Free beta (Google One AI Premium subscribers)

Anthropic

Agentic AI system for knowledge work running on desktop with file access, task scheduling, and multi-step task execution.

Default model: Claude Opus 4.6

mixed · hybrid

Pro: $20/mo · Max 5x: $100/mo · Max 20x: $200/mo

Princeton NLP Group

Research framework and agent for automated software engineering that interfaces AI models with code repositories using custom terminal-like tools.

user owned · self hosted

Free (user pays LLM API costs)