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Show HN: Plandex v2 – open source AI coding agent for large projects and tasks

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257 points danenania | 1 comments | 16 Apr 25 21:26 UTC | HN request time: 0.215s | source

Hey HN! I’m Dane, the creator of Plandex (https://github.com/plandex-ai/plandex), an open source AI coding agent focused especially on tackling large tasks in real world software projects.

You can watch a 2 minute demo of Plandex in action here: https://www.youtube.com/watch?v=SFSu2vNmlLk

And here’s more of a tutorial style demo showing how Plandex can automatically debug a browser application: https://www.youtube.com/watch?v=g-_76U_nK0Y.

I launched Plandex v1 here on HN a little less than a year ago (https://news.ycombinator.com/item?id=39918500).

Now I’m launching a major update, Plandex v2, which is the result of 8 months of heads down work, and is in effect a whole new project/product.

In short, Plandex is now a top-tier coding agent with fully autonomous capabilities. It combines models from Anthropic, OpenAI, and Google to achieve better results, more reliable agent behavior, better cost efficiency, and better performance than is possible by using only a single provider’s models.

I believe it is now one of the best tools available for working on large tasks in real world codebases with AI. It has an effective context window of 2M tokens, and can index projects of 20M tokens and beyond using tree-sitter project maps (30+ languages are supported). It can effectively find relevant context in massive million-line projects like SQLite, Redis, and Git.

A bit more on some of Plandex’s key features:

- Plandex has a built-in diff review sandbox that helps you get the benefits of AI without leaving behind a mess in your project. By default, all changes accumulate in the sandbox until you approve them. The sandbox is version-controlled. You can rewind it to any previous point, and you can also create branches to try out alternative approaches.

- It offers a ‘full auto mode’ that can complete large tasks autonomously end-to-end, including high level planning, context loading, detailed planning, implementation, command execution (for dependencies, builds, tests, etc.), and debugging.

- The autonomy level is highly configurable. You can move up and down the ladder of autonomy depending on the task, your comfort level, and how you weigh cost optimization vs. effort and results.

- Models and model settings are also very configurable. There are built-in models and model packs for different use cases. You can also add custom models and model packs, and customize model settings like temperature or top-p. All model changes are version controlled, so you can use branches to try out the same task with different models. The newly released OpenAI models and the paid Gemini 2.5 Pro model will be integrated in the default model pack soon.

- It can be easily self-hosted, including a ‘local mode’ for a very fast local single-user setup with Docker.

- Cloud hosting is also available for added convenience with a couple of subscription tiers: an ‘Integrated Models’ mode that requires no other accounts or API keys and allows you to manage billing/budgeting/spending alerts and track usage centrally, and a ‘BYO API Key’ mode that allows you to use your own OpenAI/OpenRouter accounts.

I’d love to get more HNers in the Plandex Discord (https://discord.gg/plandex-ai). Please join and say hi!

And of course I’d love to hear your feedback, whether positive or negative. Thanks so much!

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jmcpheron ◴[16 Apr 25 23:41 UTC] No.43711522[source]▶
Plandex was one of the first agentic style coating system to I tried several months ago, and it worked very well. But I've been using the cursor and windsurf style editors more recently because of their popularity. And their effectiveness is honestly pretty great.

Would you classify Plandex as more similar to a terminal interface like Claude Code? Also it looks like Open AI released a similar terminal based tool today. https://github.com/openai/codex

Do you see an obvious distinctions or pros/cons between the terminal tools and the IDE systems?

replies(1): >>43711781 #
1. danenania ◴[17 Apr 25 00:24 UTC] No.43711781[source]▶
> Would you classify Plandex as more similar to a terminal interface like Claude Code? Also it looks like Open AI released a similar terminal based tool today. https://github.com/openai/codex

Yes, I would say Plandex is generally similar in spirit to both Claude Code and OpenAI's new Codex tool. All three are agentic coding tools with a CLI interface.

A couple areas where I think Plandex can have an edge:

- Most importantly, it's almost never the case these days that a single provider offers the best models across the board for coding. Instead, each provider has their strengths and weaknesses. By slotting in the best model for each role, regardless of provider, Plandex is able to get the best of all worlds. For example, it currently uses Sonnet 3.7 by default for planning and coding, which by most accounts is still the best coding model. But for the narrow task of file edits, o3-mini offers drastically better speed, cost, and overall results. Similarly, if you go above Sonnet 3.7's context limit (200k tokens), Plandex can seamlessly move you over to a Gemini model.

- It offers some unique features, like writing all changes to a sandbox by default instead of directly to project files, that in my experience make a big difference for getting usable results and not leaving behind a mess by accident. I won't list all the features again here, but if you go through the README, I think you'll find a number of capabilities are quite helpful and aren't offered by other tools.

> Do you see an obvious distinctions or pros/cons between the terminal tools and the IDE systems?

I'm a Cursor subscriber and I use both Cursor and Plandex regularly for different kinds of tasks. For me, Cursor works better for smaller, more localized changes, while Plandex offers a better workflow for tasks that involve many steps, many files, or need many attempts to figure out the right prompt (since Plandex has more robust version control). I think once you are editing many files in one go, the IDE tab-based paradigm starts to break down a bit and it can become difficult to keep a high level perspective on everything that's changing.

Also, I'd say the terminal is naturally a better fit for executing scripts, installing dependencies, running tests and so on. It has your environment already configured, and it's able to control execution in a much more structured and reliable way. Plandex, for example, can tentatively apply a bunch of pending changes to your project, execute an LLM-generated script, and then roll back everything if the script fails. It's pretty hard to achieve that kind of low-level process control from an IDE.