# How Walden Yan actually uses coding agents

Co-founder, Cognition (Devin)

**If you take one thing:** `Daily customer-report Devin`, escalates top feature asks. his favorite Devin job is not code at all, it reads every customer report each day and escalates the top requests to engineering.

- **Agent:** Devin (web) ([source, 2026-03-19](https://x.com/walden_yan/status/2034689901892084009))
- **Model:** Fable ([source, 2026-07-13](https://x.com/walden_yan/status/2076715678242124154))
- **Model:** GPT-5.5 ([source, 2026-04-24](https://x.com/walden_yan/status/2047783217370152988))
- **Review:** Devin Review first, then asks Devin what to look at first ([source, 2026-03-19](https://x.com/walden_yan/status/2034689901892084009))
- **Harness:** Slack channel feeding a team of cloud Devins; stacked PRs ([source, 2026-03-19](https://x.com/walden_yan/status/2034689901892084009))

## In their words

> I’ve had a lot of fun pointing Devin to look at everything in a slack channel, split up the tasks automatically, and then start a team of Devin’s to tackle them.

> But then I tried it, and on one of my tasks, Fusion w/ Fable was 4x cheaper and gave a better PR.

> I find myself really reaching for 5.5 nowadays. Seems like a model built for cloud.

> Then when I go to review, I ask it to tell me what I should look at first

> I’ve had a lot of fun pointing Devin to look at everything in a slack channel, split up the tasks automatically, and then start a team of Devin’s to tackle them.


Archetype (our label): Orchestrator. Newest source: 2026-08-19.
Card: https://www.prehistoriq.com/stacks/walnutwaldo/ · Data: https://github.com/prehistoriq/stacks/blob/main/data/stacks/walnutwaldo.json