Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

How to code Claude Code in 200 lines of code

mihaileric.com

Post reply on HN
Print view View original

211–220 of 249 posts

Re: How to code Claude Code in 200 lines of code

#211

Post by jacob019 »

dunk010 wrote: post #209
jacob019 wrote: post #198

Earlier quoted context omitted.

https://github.com/jacobsparts/agentlib See CodeAgent or subrepl.py if you're just interested in the REPL orchestration. I also have a Python REPL MCP server that works with CC. It isn't published, but I could share it by request. My favorite part of code agent is the /repl command. I can drop into the REPL mid session and load modules, poke around with APIs and data, or just point Claude in the right direction. Some…

I request you to publish it! :-D

Okay, I will :)

I'll add a new repo for it, maybe this evening, and I'll reply here with a link.

Re: How to code Claude Code in 200 lines of code

#212

Post by all2 »

santiagobasulto wrote: post #191

I'm surprised this post has so many upvotes. This is a gross oversimplification of what Claude Code (and other agents can do). On top of that, it's very poorly engineered.

> Poorly engineered

How so? As a pedagogic tool it seems adequate. How would you change this to be better (either from a teaching standpoint or from a SWE standpoint)?

Re: How to code Claude Code in 200 lines of code

#213

Post by naasking »

floppyd wrote: post #100

> This is the key insight: we’re just telling the LLM “here are your tools, here’s the format to call them.” The LLM figures out when and how to use them. This really blew my mind back then in the ancient times of 2024-ish. I remember the idea of agents just reached me and I started reading various "here I built an agent that does this" articles, and I was really frustrated at not understanding how the hell LLM "know…

It would seem magical if you think of LLMs as token predictors with zero understanding of what they're doing. This is evidence that there's more going on though.

Re: How to code Claude Code in 200 lines of code

#214

Post by wxce »

mickeyp wrote: post #169
rtgfhyuj wrote: post #57

Earlier quoted context omitted.

why would it early stop? examples?

Models just naturally arrive at a conclusion that they are done. TODO hints can help, but is not infallible: Claude will stop and happily report there's more work to be done and "you just say the word Mister and I'll continue" --- this is a RL problem where you have to balance the chance of an infinite loop (it keeps thinking there's a little bit more to do when there is not) versus the opposite where it stops short…

> this is a RL problem where you have to balance the chance of an infinite loop (it keeps thinking there's a little bit more to do when there is not) versus the opposite where it stops short of actual completion.

Any idea on why the other end of the spectrum is this way -- thinking that it always has something to do?

I can think of a pet theory on it stopping early -- that positive tool responses and such bias it towards thinking it's complete (could be extremely wrong)

Re: How to code Claude Code in 200 lines of code

#215

Post by loeg »

thierrydamiba wrote: post #123
loeg wrote: post #120

Would be nice to have a different wrapper around Claude, even something bare bones, as long as it's easy to modify. Claude code terminal has the jankiest text editor I've ever used -- holding down backspace just moves the cursor. It's something about the key repeat rate. If you manually press backspace repeatedly, it's fine, but a rapid repeat rate confuses the editor. (I'm pretty sure neither GNU readline nor BSD ed…

What editor are you using?

Whatever interface you get running the claude cli.

Re: How to code Claude Code in 200 lines of code

#216

Post by jcims »

lmeyerov wrote: post #205
jcims wrote: post #190

Earlier quoted context omitted.

Mind if I ask what models you’re using for CTF? I got out of the game about ten years ago and have been recently thinking about doing my toes back in.

Yep -- one fun experiment early in the video is showing sonnet 4.5 -> opus 4.5 gave a 20% lift We do a bit of model-per-task, like most calls are sending targeted & limited context fetches into faster higher-tier models (frontier but no heavy reasoning tokens), and occasional larger data dumps (logs/dataframes) sent into faster-and-cheaper models. Commercially, we're steering folks right now more to openai / azure op…

Nice! Thank you!

I just did an experiment yesterday with Opus 4.5 just operating in agent mode in vscode copilot. Handed it a live STS session for AWS to see if it could help us troubleshoot an issue. It was pretty remarkable seeing it chop down the problem space and arrive at an accurate answer in just a few mins.

I'll definitely check out the video later. Thanks!

Re: How to code Claude Code in 200 lines of code

#220

Post by libraryofbabel »

misternugget wrote: post #164
libraryofbabel wrote: post #35

It's a great point and everyone should know it: the core of a coding agent is really simple, it's a loop with tool calling. Having said that, I think if you're going to write an article like this and call it "The Emperor Has No Clothes: How to Code Claude Code in 200 Lines of Code", you should at least include a reference to Thorsten Ball's excellent article from wayyy back in April 2025 entitled "How to Build an Age…

Hey! Thorsten Ball here. Thanks for the shout-out. I was quite confused when someone sent me this article: same "Emperor has no clothes", same "it's only x hundred lines", implements the same tools, it even uses the same ASCII colors when printing you/assistant/tool. Then I saw the "January 2025" in the title and got even more confused. So, thanks for your comment and answering all the questions I had just now about…

Hi! Thanks again for writing that first Emperor Has No Clothes blog post; like I said, it really inspired me and made everything click early on when I was first dipping my toes into the world of agents. Whenever I teach this stuff to other engineers, I often think back to that moment of realizing exactly how the exchange between LLM, tool call requests, tool functions, and agent code works and I try to get that across as the central takeaway. These days I usually add diagrams to get really clear on what happens on which side of the model api.

I do wonder whether the path here was:

1) You wrote the article in April 2025

2) The next generation of LLMs trained on your article

3) The author of TFA had a similar idea, and heavily used LLMs to help write the code and the article, including asking the LLM to think of a catchy title. And guess what title the LLM comes up with?

There are also less charitable interpretations, of course. But I'd rather assume this was honestly, if sloppily, done.

Post reply on HN