Open-source composable toolkit for building AI agents in JavaScript.
AgentsKit.js is an open-source (MIT) composable toolkit for building AI agents in JavaScript/TypeScript: a tiny 10KB core with six formal contracts, plus 22 plug-and-play packages for model adapters, UI bindings (React, terminal, Vue, Svelte), autonomous runtime, tools, skills, memory, RAG, sandboxing, observability, and evaluation. Swap any layer without rewriting, with 25 native model adapters and an MCP server for Claude Desktop, Cursor, and Windsurf.
| Pricing | Open Source |
|---|---|
| Category | Coding & Development |
| Platforms | windows, macos, linux |
| Company | AgentsKit |
| Official website | www.agentskit.io |
The right coding tool depends on where you write code and how much of your codebase it can understand. IDE integration is the first filter — a tool that lives in your editor, sees your project files and respects your stack will help far more than a general chatbot you paste snippets into. Look for accurate completions, clear explanations of suggested changes, and strong refactoring and debugging support for your main languages. Privacy deserves real attention: check whether your code is used for training, and whether a self-hosted or enterprise option exists for sensitive projects. Price against the hours it actually saves — most developers feel the difference within the first week of real use.
AgentsKit.js is an open-source (MIT) composable toolkit for building AI agents in JavaScript/TypeScript: a tiny 10KB core with six formal contracts, plus 22 plug-and-play packages for model adapters, UI bindings (React, terminal, Vue, Svelte), autonomous runtime, tools, skills, memory, RAG, sandboxing, observability, and evaluation. Swap any layer without rewriting, with 25 native model adapters and an MCP server for Claude Desktop, Cursor, and Windsurf.
AgentsKit.js offers 10KB zero-dependency core with six formal contracts, 25 native model adapters (OpenAI, Anthropic, Gemini, local), Autonomous ReAct runtime with multi-agent delegation, Chat UIs for React, terminal, Vue, Svelte, and more, Memory, RAG, skills, and tool registries, Sandboxed code execution and observability, CLI scaffolds skills, tools, and adapters and Exposes tools as MCP server for major editors.
AgentsKit.js is open source, so the software itself is free to download, use and self-host. Your only costs are the infrastructure you run it on and any paid services you connect to it.
Strengths of AgentsKit.js include Genuinely modular: swap any layer.; Tiny core with no lock-in.; Broad model and UI coverage.. On the downside, 0.x packages are still stabilizing; only core is v1.; JavaScript-only ecosystem.; Docs and ecosystem assume JS/TS fluency..
by JetBrains
JetBrains' open-source agentic IDE built around the pi coding agent — every task runs in its own isolated git-worktree workspace with a spec graph the agent actually reads, so parallel agents never wreck your main checkout
Best for: Developers running parallel coding agents who want worktree isolation and a spec graph the agent actually reads
Pricing: Open Source
Limitation: Requires git and an authenticated pi provider — it does not work without them
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Best for: AI agent developers who need fast, light browser fetching, extraction and automation
Pricing: Open Source
Limitation: Full visual capabilities need the --layout flag
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Pricing: Open Source
Limitation: Mac only — macOS 15 or later, and made for MacBooks with a notch
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Best for: Non-coders and small teams who want a playable mobile game from a description
Limitation: Pricing details are shown only as an image on the homepage, not as readable text
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Best for: Claude Code and Codex users who keep burning their weekly allowance early
Pricing: Freemium
Limitation: Stale readings can make a pause late, and requests already in flight or tools outside hook coverage are not stopped
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Phone remote for coding agents already running in tmux: each session appears as a chat, and permission prompts and questions arrive as buttons whose tap is typed into the same terminal pane
Best for: Developers who run coding agents in tmux and want to steer them from their phone
Pricing: Open Source
Limitation: The phone app is Android-only; iPhone users must use the browser hub instead
