Live data from Hacker News

Agentic Engineering Patterns

simonwillison.net

11–20 of 341 posts

Re: Agentic Engineering Patterns

#11
post #7

Is there a market for this like OOP patterns that used to sell in the 90s?

The underlying technology is still improving at a rapid pace. Many of last year's tricks are a waste of tokens now. Some ideas seem less fragile: knowing two things allows you to imagine the confluence of the two so you know to ask. Other things are less so: I'm a big fan of the test-based iteration loop; it is so effective that I suspect almost all users have arrived at it independently[0]. But the emergent properties of models are so hard to actually imagine. A future sufficiently-smart intelligence may take a different approach that is less search and more proof. I wouldn't bet on it, but I've been surprised too many times over the last few years.

0: https://wiki.roshangeorge.dev/w/Blog/2025-12-01/Grounding_Yo...

Re: Agentic Engineering Patterns

#12

I use AI in my workflow mostly for simple boilerplate, or to troubleshoot issues/docs. I've dipped into agentic work now and again, but never been very impressed with the output (well, that there is any functioning output is insanely impressive, but it isn't code I want to be on the hook for complaining). I hear a lot of people saying the same, but similarly a bunch of people I respect saying they barely write code a…

When was the last time you tried?

I think trying agents to do larger tasks was always very hit or miss, up to about the end of last year.

In the past couple of months I have found them to have gotten a lot better (and I'm not the only one).

My experience with what coding assistants are good for shifted from:

smart autocomplete -> targeted changes/additions -> full engineering

Re: Agentic Engineering Patterns

#14

I use AI in my workflow mostly for simple boilerplate, or to troubleshoot issues/docs. I've dipped into agentic work now and again, but never been very impressed with the output (well, that there is any functioning output is insanely impressive, but it isn't code I want to be on the hook for complaining). I hear a lot of people saying the same, but similarly a bunch of people I respect saying they barely write code a…

I was in the same boat as you until I saw DHH post about how he’s changed his use of agents. In his talk with Lex Fridman his approach was similar to mine and it really felt like a kernel of sanity amongst the hype. So when he said he’s changed his approach I had another look. I’m using agents (Claude code) every day now. I still write code every day too. (So does Dax Raad from OpenCode to throw a bit more weight behind this stance). I’m not convinced the models can own a production code base and that therefore engineers need to maintain their skills sufficiently to be responsible. I find agents helpful for a lot of stuff, usually heavily patterned code with a lot of prior art. I find CC consistently sucks at writing polars code. I honestly don’t enjoy using agents at all and I don’t think anyone can honestly claim they know how this is going to shake out. But I feel by using the tools myself I have a much stronger sense of reality amongst the hype.

Re: Agentic Engineering Patterns

#15
For web apps, explictly asking the agent to build in sensible checkpoints and validate at the checkpoint using Playwright has been very successful for me so far. It prevents the agent from strating off course and struggling to find its way back. That and always using plan mode first, and reviewing the plan for evidence of sensible checkpoints. /opusplan to save tokens!

Re: Agentic Engineering Patterns

#16
I primarily use AI for understanding codebases myself. My prompt is:

"deeply understand this codebase, clearly noting async/sync nature, entry points and external integration. Once understood prepare for follow up questions from me in a rapid fire pattern, your goal is to keep responses concise and always cite code snippets to ensure responses are factual and not hallucinated. With every response ask me if this particular piece of knowledge should be persistent into codebase.md"

Both the concise and structure nature (code snippets) help me gain knowledge of the entire codebase - as I progressively ask complex questions on the codebase.

Re: Agentic Engineering Patterns

#17
I really like the idea of agent coding patterns. This feels like it could be expanded easily with more content though. Off the top of my head:

- tell the agent to write a plan, review the plan, tell the agent to implement the plan

- allow the agent to “self discover” the test harness (eg. “Validate this c compiler against gcc”)

- queue a bunch of tasks with // todo … and yolo “fix all the todo tasks”

- validate against a known output (“translate this to rust and ensure it emits the same byte or byte output as you go”)

- pick a suitable language for the task (“go is best for this task because I tried several languages and it did the best for this domain in go”)

Re: Agentic Engineering Patterns

#18
Is there anything about reviewing the generated code? Not by the author but by another human being.

Colleagues don’t usually like to review AI generated code. If they use AI to review code, then that misses the point of doing the review. If they do the review manually (the old way) it becomes a bottleneck (we are faster at producing code now than we are at reviewing it)

Re: Agentic Engineering Patterns

#19

I use AI in my workflow mostly for simple boilerplate, or to troubleshoot issues/docs. I've dipped into agentic work now and again, but never been very impressed with the output (well, that there is any functioning output is insanely impressive, but it isn't code I want to be on the hook for complaining). I hear a lot of people saying the same, but similarly a bunch of people I respect saying they barely write code a…

My experience is that the first iteration output from a single agent is not what I want to be on the hook for. What squares it for me with "not writing code anymore" is the iterative process to improve outputs:

1) Having review loops between agents (spawn separate "reviewer" agents) and clear tests / eval criteria improved results quite a bit for me. 2) Reviewing manually and giving instructions for improvements is necessary to have code I can own

Re: Agentic Engineering Patterns

#20
post #12

I use AI in my workflow mostly for simple boilerplate, or to troubleshoot issues/docs. I've dipped into agentic work now and again, but never been very impressed with the output (well, that there is any functioning output is insanely impressive, but it isn't code I want to be on the hook for complaining). I hear a lot of people saying the same, but similarly a bunch of people I respect saying they barely write code a…

When was the last time you tried? I think trying agents to do larger tasks was always very hit or miss, up to about the end of last year. In the past couple of months I have found them to have gotten a lot better (and I'm not the only one). My experience with what coding assistants are good for shifted from: smart autocomplete -> targeted changes/additions -> full engineering

I’m not OP but every time I post a comment with this sentiment I get told “the latest models are what you need”. If every 3 months you are saying “it’s ready as long as you use the latest model”, then it wasn’t ready 3 months ago and it’s not likely to be ready now.

To answer your question, I’ve tried both Claude code and Antigravity in the last 2 weeks and I’m still finding them struggling. AG with Gemini regularly gets stuck on simple issues and loops until I run out of requests, and Claude still just regularly goes on wild tangents not actually solving the problem.

Post reply on HN