“The planning agent is responsible for the actual thinking, so it should run on your most powerful model. I initially used Fable for this purpose when it was available, as it excels in UI/UX design. When Fable was no longer accessible, I switched to Opus. Since the planner writes the specifications, the implementation can be handled by a more cost-effective and faster model like Sonnet.”
Noah Blauensteiner, Author, Xebia articles. Describes a factory he set up himself; Xebia sells AI consulting and training, so promotional framing is possible.
Xebia sells AI or agent tooling, so it has a reason to publish flattering numbers about AI. The passage stays in the archive; read it with that in mind.
How this was checked
Checked against the source by a first reader, then confirmed independently by a second reader who fetched the source without seeing the first reader's notes (Independent review agent (Claude Sonnet), blind second pass from passage text and citation only, no repository access, 2026-10-31).
Exact match for the full passage, from 'The planning agent...' through '...like Sonnet.' The author is Noah Blauensteiner.
How to cite this passage
Noah Blauensteiner (Xebia), “Shining Some Light in Dark Agentic Software Factories”, Xebia articles, 2026-08-12, at What is an Agentic Software Factory?. https://xebia.com/articles/shining-some-light-in-dark-agentic-software-factories/ Archived at https://the-ai-record.com/passages/xebia-planning-agent-runs-your-most-powerful-2026
Xebia