3. Fable 5 Without the Token Anxiety

Orchestrate with the big model, execute with cheap ones, and plan in artifacts instead of plan mode

Episode 3 of Build with Agents. Two things this time: the delegation setup that keeps my Fable 5 limits sane even when I am coding all day, and why I stopped using plan mode in favor of a living artifact.

The best model, and the hungriest

We all felt it last December when Opus 4.5 launched. Everything you threw at it just felt right. It got your intent, it debugged well, it figured things out. And then no model gave me that feeling again, until Fable 5. This is a great time to be building.

The problem is Fable 5 consumes tokens aggressively. You live in constant token anxiety: “I am running out, I need more, this model is too good to stop using.” And I think Anthropic will eventually move it to API-based pricing. Who knows when, but it is coming.

So the question becomes: how do you keep this level of intelligence available without burning through tokens?

Plan big, execute small

I wrote the full thesis, the router-era argument and the economics, in The LLM Router Era Starts with Fable 5. This episode is the practice.

Full write-up, the router-era thesis plus the skill to copy: here

Stop using plan mode

Second thing from the video. I truly believe plan mode was created because models were not good enough. Sitting in a loop of planning, planning, planning, reading long documents before anything happens, is counterintuitive now. At least it was for me.

Peter Steinberger made this argument way ahead of time in “Just Talk To It”: do not ceremonialize planning, talk to the agent like you would talk to a pair programmer and iterate with it. So I start in auto mode and just chat.

The iteration is fun, but sometimes you want to see things visually: the plan, the design decisions, the architecture. This is where Claude artifacts changed my workflow. Instead of downloading HTML files and reopening them over and over, I ask Claude to maintain a single artifact of everything it is doing: every design decision, every architectural call, all the implementation details. I keep it open in a browser tab, refresh it, and iterate on top of it.

It matters most at review time. Agents write code really fast, and I do not want to be the bottleneck, developer ego and all. The best way to review is end to end: queue it up, ask the agent to help you review, have it generate component diagrams in the artifact, and move through the code quickly instead of pretending you will read every line.

That is the episode. Fable 5 plans big, cheaper models execute small, and the plan lives in an artifact instead of plan mode. More videos coming. Thank you.