How to use Cursor to separate design from coding
A solo developer used separate Cursor architect and programmer windows, with written instructions preceding implementation, and reported less architectural drift.
news.ycombinator.com
Prompt to try
Editorial adaptation, not the source author’s exact prompt. Replace bracketed inputs and review tool permissions first.
Act as the architect for [project]. Define boundaries, interfaces, constraints, and examples for [change] without writing production code. Produce instructions for a separate programmer agent, then review its diff against those contracts.
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See placements →What happened
The author reports much less logical drift and greater coherence in the growing codebase, while noting costs of roughly $100 a day at their current pace.
Reported by garylauchina on Hacker NewsHow the agent did it
- Clarified requirements and trade-offs with Perplexity and ChatGPT.
- Used an architect Cursor window to write boundaries and contracts.
- Used a programmer Cursor window to implement the written tasks.
Where a person stepped in
The developer assigns roles and requires written architecture before every non-trivial implementation; the architect also reviews diffs.
A person approved each step before the agent continued.
A solo developer described using Cursor on a complex systems measurement project that had reached V12 and more than 30,000 lines. The problem was architectural drift: generated functions could look correct locally while breaking earlier decisions and long-range invariants. The author attributed this to asking one assistant to handle requirements, architecture, and implementation under limited context.
They split the work into distinct roles. Perplexity and ChatGPT handled requirements, trade-offs, and high-level architecture outside the IDE. A Cursor window using GPT-5.2 served as the architect. It defined module boundaries, interfaces, contracts, design notes, and developer guides, and reviewed diffs. It was prohibited from writing production code.
A second Cursor window using Sonnet 4.5 implemented the architect's specific tasks, following written instructions and style rules. Every non-trivial change began with design text before implementation. The author reported much less logical drift and a codebase that felt more coherent than earlier, smaller iterations. They also noted a substantial downside: at their current pace, Cursor cost something like $100 per day.
Who it's for: Solo developers whose coding agents lose architectural context as a project grows.
Prompt
Suggested prompt (written by Agents In Use, not the author's)
Source: Hacker News · garylauchina
Frequently asked questions
What was the architect allowed to do?
The GPT-5.2 Cursor instance wrote design notes and guides, defined interfaces and contracts, and reviewed diffs. The author explicitly prohibited it from writing production code.
How did the programmer receive work?
The Sonnet 4.5 Cursor instance implemented specific files, functions, and refactors described by the architect, following explicit written instructions and style rules.
More details
About this account
The architect produces design prose and reviews diffs; the programmer implements constrained tasks without redesigning the system.
Platform: Hacker News. Attribution: https://news.ycombinator.com/item?id=46462910. Prompt: Suggested (written by Agents In Use, not the author's). Sourced by the Agents In Use pipeline.
Credit: garylauchina on Hacker News
Source published 2 Jan 2026
Source checked 14 Oct 2026
Tools and topics
Cursor · Perplexity · ChatGPT
Architecture · Agent roles
Editorial completeness: 100/100. Measures documented fields, not agent performance or verified outcomes.