---
title: "Theo Browne: Please stop using stupid models"
description: "Theo Browne argues that model reliability matters more as agent work gets wider and longer."
plain: "Theo says a model's ordinary performance matters more than its best result when an agent runs for a long time."
group: source
speaker: "Theo Browne"
date: 2026-09-18
url: https://youtu.be/iBrAWpjXNxs
sources:
  - url: https://youtu.be/iBrAWpjXNxs
    title: "Please stop using stupid models - YouTube"
    publisher: "Theo Browne"
    note: "Recording; used for model reliability over wider and longer agent runs."
    accessed: "2026-10-01"
---

# Theo Browne: Please stop using stupid models

> For agents: start with the [agent guide](https://ratstack.sh/llms.txt). Every page is Markdown by default; add `Accept: text/html` for HTML.

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Theo argues that a model's ordinary performance matters more than its best result when an agent runs for a long time. Short tasks hide differences between models; wider tasks create more chances for failure. [04:19](https://youtu.be/iBrAWpjXNxs?t=259) [07:24](https://youtu.be/iBrAWpjXNxs?t=444) [17:07](https://youtu.be/iBrAWpjXNxs?t=1027)

He urges teams to learn from long runs and change their prompts and codebases when runs fail. [12:13](https://youtu.be/iBrAWpjXNxs?t=733) [12:53](https://youtu.be/iBrAWpjXNxs?t=773)

## Sources

1. [Please stop using stupid models - YouTube](https://youtu.be/iBrAWpjXNxs)
   Theo Browne. Recording; used for model reliability over wider and longer agent runs. Accessed 2026-10-01.

## Linked from

- Agent guide → An Effect stack so pure (aspirational) Kit Langton will blush. → [Read page](https://ratstack.sh/llms.txt)

- Change log → What changed in the files served here, newest first. → [Read page](https://ratstack.sh/log)

- Floor and ceiling → Theo Browne argues that a model's ordinary reliability matters more than its peak on long agent runs. → [Read page](https://ratstack.sh/lore/floor-and-ceiling)

- Full agent guide → An Effect stack so pure (aspirational) Kit Langton will blush. → [Read page](https://ratstack.sh/llms-full.txt)

- Rat Stack lore | rat-stack → Short, source-grounded notes on the ideas and decisions behind rat-stack. → [Read page](https://ratstack.sh/lore)

- Source change history (log.md) → The generated change log as Markdown. → [Read page](https://ratstack.sh/log.md)