Stackness
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Document system architecture and intent explicitly as agents write more code

by Stackness

DevOps & Infrastructure

Keep an explicit, living record of why a system is built the way it is, not just what the code does, so that as AI agents generate a growing share of the codebase, humans and future agents can still reconstruct the original intent and tradeoffs. In practice this means maintaining architecture decision records or an equivalent document alongside the code, updated as decisions are made rather than reconstructed after the fact.

What it is

As AI agents write a growing share of a codebase, the real risk is not bad code but a loss of shared understanding of why the system looks the way it does. Keeping an explicit, living record of architecture and intent is a way to preserve that understanding so both humans and agents can reconstruct the reasoning behind decisions instead of guessing from the code alone.

How to do it

  • Keep a lightweight architecture decision record (ADR) or equivalent document in the repository, next to the code it describes.
  • Write an entry whenever a meaningful decision is made: what was chosen, what alternatives existed, and why the choice was made.
  • Update the record as part of the change itself, not as a cleanup task afterward, so intent is captured while it is still fresh.
  • Reference these records from code comments, pull requests, or commit messages so an agent reading the code has a path back to the reasoning.
  • Treat the document as a living artifact: revise or retire entries when decisions change rather than letting them go stale.

When it helps

This practice matters most once agents are producing a significant portion of the code, because nobody on the team may have personally written or reviewed every line. A living architecture record gives both new team members and future agents a way to recover intent instead of reverse-engineering it from behavior alone.

Pitfalls

The value of this move depends entirely on the record being updated at the time decisions are made. If it is reconstructed later, after memory of the original reasoning has faded, it risks becoming an inaccurate or incomplete account rather than a trustworthy source of truth. A document that is not kept current can end up worse than no document at all, since it creates false confidence that intent has been preserved.

Sources