Prelude – a tiny CLI tool building context prompts from your code

I was feeling bogged down by the repetitive copy-paste routine to build context prompts for debugging or generating code. This simple solution ended up saving me a lot of time, so I thought I'd share my workflow.

With the large context windows of OpenAI and Anthropic models, you can keep entire code repositories in context. But copy-pasting the file-tree and code from lots of places is annoying. Prelude is a tiny CLI tool that creates a context prompt from files in your directory and its subdirectories, then copies it to your clipboard or saves it to a text file. Prelude creates a prompt containing the file tree of your specified directory, minus the files you ignored in .gitignore and .preludeignore, followed by the content of each file. It adds a bit of context prompting at the end, and that's it. Ready to copy-paste into a new chat with your favorite AI-chat. Nothing more, nothing less. Here’s how it works:

Install Prelude with Homebrew:

brew tap aerugo/prelude brew install prelude

Simply run prelude in your working directory. Need files from a specific subdirectory? Use prelude -p dir. Want to specify a filename to save the prompt? Use prelude -f prompt.txt. Lots of files you don't want in the prompt? Put them in a .preludeignore file in the root folder where you run Prelude

Say that you know the names of the files you want to include, for example FooBar.py and BarFoo.md and they are somewhere in your file hierarchy.

Just run

prelude -M "foobar|barfoo"

and you will get a prompt with only those files. It also works with * wildcards.

Of course, it also works with the -P option, so you can also run something like

prelude -P backend/src -M "*.py"

To get all python files in the src directory of your backend.

PS. I'm sure this already exists. Lots of people must have done this. But nevertheless, I couldn't find a simple CLI tool to do just this, so I wrote one for myself, and then thought to share it.

I know this is a bit heavier since it's a whole program:

https://aider.chat/ generates a repo map, suggests related files, then makes your request and does the editing for you. (with intelligent diff for models that work well.)

They have a leaderboard for models for editing and what mode they use: https://aider.chat/docs/leaderboards/

EDIT: Oh, it looks like you're dumping the entire repo. Well, sure, I guess. Once it seems too big you can select just what you need. Also gui tools like the open source https://www.continue.dev/ lets you pick files, search codebase via RAG, add docs, etc...

Sounds a bit like code2prompt - https://github.com/mufeedvh/code2prompt

I was asked in a PM how I use the prompts. Basically, whenever I need to write some new code for a project, I start by making a prompt out of the relevant parts of the repo, paste it into GPT or Claude, and follow up with something like (random made up example):

——

I want to add a feature to my Content.js component. In the table that displays names of animals, I want to add an Edit button in a new column on each row. When clicked, it should bring up a modal that allows me to edit the name and emoji of the animal.

Review my codebase to see how CRUD actions are implemented for other features. Make sure you follow the established code patterns in the project.

Before starting to code, consider best practices for UX of a feature like this and make sure the implementation is user friendly and follows best practices.

After reviewing the code, describe how you will implement the feature make a plan for how to implement. After that, write the complete code for the implementation.

I've been maintaining my own script that does something like this. A few things I've found to be useful: It can also pull in context from git history (prioritize based on which files have been most recently worked on, include recent git commit messages which can help the LLM know more about what's going on), and optionally it can go do multiple stages... for long files, first summarizing them, then including the summary in the final prompt.

I personally think a GUI tool would provide better user experience since you can see the files, pick which ones to include as context, and check the prompt generated in real-time.

So I built my own GUI version of this (plus a lot of other quality of life features): https://prompt.16x.engineer/

I made one too like this too, it would use .gitignore like files (.gptignore) to filter what goes into the prompt.

Just FYI if anyone runs into this: I made a few updates to Prelude in the last few days. It now allows including only files tracked by git by using the -g option. You can also toggle case sensitivity of pattern matching (case insensitive by default) with the -c option.

New release https://github.com/aerugo/prelude/releases/tag/v0.3 and pushed to the Homebrew formula

I made something like this too to use myself. It's called `describe dot` and builds a context by recursing over . and putting all the content into the clipboard. It respects the .gitignore files in each folder and I can add .dignore files to ignore more files. At the end it creates a text file folder structure followed by the contents of all the files. It also logs the files in size order so that you can trim down the total size by ignoring them. It's been useful for small projects but I imagine that a whitelist based approach might be more useful for larger ones.

Wrote something similar[1] using Go a while back, but I love that this one only uses shell tools. Extremely useful when working with LLMs for small to medium projects.

For bigger ones on the other hand, I wish I could just get the exact context I need. Maybe something like only the files open in vim?

[1]: https://git.sr.ht/~jamesponddotco/llmctx

Have a bunch of Makerile commands (pbcopy-api, pbcopy-ui, pbcopy-curr) that use some mishmash of git ls-files, grep, xargs tail -n +1 piped into pbcopy.

Kitchen sink command: pbcopy-all: git ls-files | xargs tail -n +1 | pbcopy

Works like a charm in Q2 2024.

I’m sure this will be a very solved problem by 2025.

To pile on, I was also going to make something similar for a very similar need (surprisingly hard to find prior art in this area that's good, probably due to so many people doing this)

But I will try this once I'm back from PTO!

Something like Prelude seems like it could complement steps before, or after it with a tool like CrewAI. Is anyone using CrewAI, or something like it in their workflow as well?

Nice job! I wrote a bash script that does the exact same thing a couple weeks ago. I didn’t even think to make it its own project.

A similar thing I've been thinking about is extracting open github issues and using LLMs to triage them. Might look into that.

I'd like to suggest adding an example of the output before the install instructions. Show don't tell...

If you have a repository, while still in it's early stages, TxtRepo.com is a good option (it can also do PRs)

Heh, I built my own tool to do this that largely depends on awk

This is pretty cool :)