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

181–190 of 249 posts

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

#181

Post by utopiah »

pbw wrote: post #156

I have mixed feelings about the "Do X in N lines of code" genre. I applaud people taking the time to boil something down to its very essence, and implement just that, but I feel like the tone is always, "and the full thing is lame because it's so big," which seems off to me.

I do prototyping for a living and ... I definitely do "X in 1/100th lines of code" regularly.

It's exciting, liberating... but it's a lie. What I do is to get the CORE of the idea so that I fully understand it. It's really nice because I get a LOT of millage very quickly... but it's also brittle, very brittle.

My experience is that most projects are 100x bigger than the idea they embody because the "real World" is damn messy. There are always radically more edge cases than the main idea enables. At some point you have to draw a line but the furthest away you draw the line, the more code you need to do it.

So... you are right to have mixed feeling, the tiny version is only valuable to get the point but it's not something one can actually use in production.

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

#182

Post by vinhnx »

This reminds me of Amp's article last year[1]. I building my own coding agent [2]. Two goals: understand real-world agent mechanics and validate patterns I'd observed across OpenAI Codex and contemporary agents.

The core loop is straightforward: LLM + system prompt + tool calls. The differentiator is the harness, CLI, IDE extension, sandbox policies, filesystem ops (grep/sed/find). But what separates effective agents from the rest is context engineering. Anthropic and Manus has published various research articles around this topic.

After building vtcode, my takeaway: agent quality reduces to two factors, context management strategy and model capability. Architecture varies by harness, but these fundamentals remain constant.

[1] https://ampcode.com/how-to-build-an-agent [2] https://github.com/vinhnx/vtcode [3] https://www.anthropic.com/engineering/building-effective-age...

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

#183

Post by mirzap »

The "200 lines" loop is a good demo of the shape of a coding agent, but it’s like "a DB is a B-tree" - technically true, operationally incomplete.

The hard part isn’t the loop - it’s the boring scaffolding that prevents early stopping, keeps state, handles errors, and makes edits/context reliable across messy real projects.

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

#184

Post by lucideer »

This is a really great post, concise & clear & educational. I do find the title slightly ironic though when the code example goes on to immediately do "import anthropic" right up top.

(it's just a http library wrapping anthropic's rest API; reimplementing it - including auth - would add enough boilerplate to the examples to make this post less useful, but I just found it funny alongside the title choice)

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

#185

Post by embedding-shape »

fastball wrote: post #142
embedding-shape wrote: post #67

Earlier quoted context omitted.

Not all models are trained with long one-shot task following by themselves, seems many of them prefer closer interactions with the user. You could always add another layer/abstraction above/below to work around it.

Can't this just be a Ralph Wiggum loop (i.e. while True)

Sure, but I think just about everyone wants the agent to eventually say "done" in one way or another.

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

#187

Post by ramoz »

fastball wrote: post #139
lmeyerov wrote: post #63

Something I would add is planning. A big "aha" for effective use of these tools is realizing they run on dynamic TODO lists. Ex: Plan mode is basically bootstrapping how that TODO list gets seeded and how todos ground themselves when they get reached, and user interactions are how you realign the todo lists. The todolist is subtle but was a big shift in coding tools, and many seem to be surprised when we discuss it -…

Planning mode actually creates whole markdown files, then wipes the context that was required to create that plan before starting work. Then it holds the plan at the system prompt level to ensure it remains top of mind (and survives unaltered during context compaction).

I don’t think it wipes the context window.

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

#188

Post by justanotherprof »

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…

I am glad you pointed out Thorsten Ball's truly excellent article: I was about to add a comment to that effect!

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

#189

Post by justanotherprof »

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…

Many thanks for your article, it was one of the true "aha" moments for me in 2025! It is a shame that your work is apparently being appropriated without attribution to sell an online course...

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

#190

Post by jcims »

lmeyerov wrote: post #63

Something I would add is planning. A big "aha" for effective use of these tools is realizing they run on dynamic TODO lists. Ex: Plan mode is basically bootstrapping how that TODO list gets seeded and how todos ground themselves when they get reached, and user interactions are how you realign the todo lists. The todolist is subtle but was a big shift in coding tools, and many seem to be surprised when we discuss it -…

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.
Post reply on HN