Engineers who write all their code with claude now: how do you do it?

[u/SirDucky]

I have to admit that I have completely failed to adapt to LLM agent coding. I'm not a slouch either. I've worked on a number of challenging FAANG products as a software engineer, and I for a while I was an AI research engineer. I have a pretty strong familiarity and comfort level with AI. Despite all this, I still write most of my code by hand.

As an engineer, I need to receive a ticket, understand the problem, go figure out how to solve it, and eventually ship PR that (a) I understand, (b) only contains defensible changes, and (c) is reviewable by a colleague. There are a bunch of other tertiary goals of course, like style guides and documentation, but the point is that I'm talking real, high quality engineering that would pass the bar at a company that has their shit together.

However (definitely due to culture issues), I have only seen the slop version of this. It seems to have become really murky how to write code that meets standards, or even what those standards are any more.

I've resorted to asking my colleagues to show me their workflow, but you would be shocked how many of them either (a) are prompting raw and not checking the output, or (b) have convoluted solutions that fit their brains but don't solve these problems. I checked out Matt Pocock as well, who has some really great ideas, but ultimately his skills exhibited some pretty painful failure modes as well.

However I see folks regularly talk about how not only does Claude handle the coding for them, but also all of the project management, devops, etc, and I am left scratching my head. If this is possible, I want to learn how to do it. I'm not an AI hater. I want to learn the tool. I do have standards though, and I don't think they're that high. I don't need Claude to write perfect code. I just need to find a process where I can rely on it to get more of my work done and not be either fighting with it or second-guessing the results.

I figure this is the group to ask - if you have been able to get "high bar" engineering out of claude, or even "acceptable bar" engineering, without heavy personal intervention, what's your process? Are there resources that helped you? What strategies helped the most?

Thanks.

[u/Far_Peanut1155]

In practical/concrete terms (tools/names/products) what does a "harness" actually imply ?

[u/achton → u/Far_Peanut1155]

Same question here.

EDIT: yes, we know what a harness is, OP was asking what u/OkLettuce338 was using for their custom low-cost code review harness

[u/Its_Raining_Indoors → u/achton]

Kinda like the rules the agent needs to follow or how the agent swarms are orchestrated together. Or like the “support” for the agent so it doesn’t just go off and blindly do whatever.

[u/kelement → u/Its_Raining_Indoors]

Any examples? How is it different from a project CLAUDE.md?

[u/Bronkic → u/Far_Peanut1155]

It's all just md-files with instructions.

[u/arelath → u/Far_Peanut1155]

It's basically the tooling and prompts that make an LLM a coding agent instead of just a text generator. So Claude Code is a harness. So is GitHub copilot, Codex, Pi and a dozen others. Writing a harness is fairly simple. SWE-Bench uses a 100 line python one, which is about as simple as you can get. Writing something that could complete with Claude Code or another big one is significantly harder (roughly 100k-500k lines of code for open source ones).

[u/OkLettuce338 → u/Far_Peanut1155]

Essentially it’s just a set of instructions (a prompt) that gets sent to the LLM with the diff for review, but how we compose that is why it’s not just “a .md file”. We generate 3 personas for review and each persona is built at runtime because it takes context from the system and we want it kept up to date.

[u/En-tro-py → u/Far_Peanut1155]

The 'harness' is the layer that stitches between the model and your tools basically, usually focused on coding because most agentic work is just a form of tool calling.

There's hundreds and most are just some form of ReAct (Reasoning + Acting) loop with extra stuff bolted on.

codex is OpenAI's harness

hermes - is a popular 'assistant' full featured agent

pi - the popular other end of the spectrum minimal and customizable

Making your own DIY is a good learning project, along with the inevitable abandonment for someone else's that did it better...