I quote the work, not the hours. Eight weeks, fixed scope, a number you can put in a budget. If I’m wrong about the estimate, that’s my problem to solve, not a line item on your invoice.

This only works because I write the code myself. There’s no team to staff, no margin to pad, no handoff where the estimate quietly doubles. You’re hiring the person doing the work.

Concrete beats abstract. A fixed number you can plan around beats a rate card and a hope.

For a complex feature I write a spec and hand it to the agent to turn into an implementation plan. What goes in it:

• Introduction. “You are building a dashboard to change settings on a security platform.”
• Problem. If it knows why, it finds solutions I didn’t think of.
• Scope. Keeps it focused on what I want.
• Out of scope. Paradoxically, this sharpens the scope.
• Functional requirements. The list of tasks to complete.
• Non-functional requirements. Respects my architectural decisions.
• References and glossary. Points it at the knowledge it should read.

The spec is where the thinking happens. The code is the easy part.

• ChatGPT Business: 30 dollars
• Claude Pro: 20 dollars
• Gemini Enterprise: 21 dollars

Unless you’re on a Business plan, OpenAI and Gemini train on your data. More on that here.

That’s 71 dollars per person on starter plans, and it climbs the moment you exhaust the quotas. Expensive, and hard to control securely at scale.

One subscription, all three, or something else entirely is a real decision.

Jevons paradox: when a technology makes a resource more efficient to use, total consumption of that resource often goes up. Lower cost raises demand and creates more work overall.

When steam engines got fuel efficient, coal consumption rose. It started the industrial revolution, not its end.

I’ve felt it firsthand, testing 43 files in an hour. GitHub’s data shows developers using Copilot write more code, not less. Features that took weeks now get prototyped in hours by one engineer.

The question is whether you cut headcount or raise throughput.

GitHub’s research on Copilot and developer productivity.