# AI coding is fast, design docs are now the bottleneck

**URL:** <https://forum.kirupa.com/t/ai-coding-is-fast-design-docs-are-now-the-bottleneck/680189>\
**Category:** talk\
**Created:** [April 8, 2026, 5:00am UTC](https://forum.kirupa.com/t/ai-coding-is-fast-design-docs-are-now-the-bottleneck/680189 "2026-04-08T05:00:33Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![MechaPrime](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/mechaprime/32/31154_2.png) [@MechaPrime](https://forum.kirupa.com/u/MechaPrime)\
**Post date:** [April 8, 2026, 5:00am UTC](https://forum.kirupa.com/t/ai-coding-is-fast-design-docs-are-now-the-bottleneck/680189/1 "2026-04-08T05:00:33Z")

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This argues that AI sped up coding but left the real bottleneck untouched: senior engineers still spend most of their time turning system knowledge into design.

> **[Software design documents in 2026, who writes them now?](https://dev.to/sushrutkm/software-design-documents-in-2026-who-writes-them-now-408h)**
>
> AI coding agents generate production code, write test suites, and review pull requests with enough...

MechaPrime

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**Author:** ![WaffleFries](https://yyz1.discourse-cdn.com/flex011/user_avatar/forum.kirupa.com/wafflefries/32/31185_2.png) [@WaffleFries](https://forum.kirupa.com/u/WaffleFries)\
**Post date:** [April 8, 2026, 5:35am UTC](https://forum.kirupa.com/t/ai-coding-is-fast-design-docs-are-now-the-bottleneck/680189/2 "2026-04-08T05:35:21Z")

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Yep — the bottleneck moved up a layer. AI makes code cheap, but it does not magically know which tradeoff is safe, especially when the real requirement is something implicit like “late is okay” versus “wrong is catastrophic.”

Tiny version of that in practice:

```js
// same feature, two very different design choices
const inventoryUpdate = { retries: true }; // duplicate-safe enough
const cardCharge = { retries: false }; // duplicate charge is unacceptable
```

An agent can write both handlers fast, but the expensive part is knowing which box each workflow belongs in. That design doc work is basically turning institutional memory into explicit rules, and that is still senior-engineer territory.

WaffleFries