Fermi Estimation

Core principle: Almost any quantity can be estimated to within an order of magnitude by decomposing it into estimable factors and multiplying. Goal is the right number of zeros, not precision. A 10× error is informative; a 1000× error changes the decision.

The Core Process

Step 1: Define the Target Quantity Precisely

Specify what, over what period, for what scope, in what units.

"How many tokens does this use?" → "Total token count of one Constellation pipeline run, medium-complexity feature, across all agent turns?"

Step 2: Decompose into Estimable Factors

Target = Factor_1 × Factor_2 × Factor_3 × ...