3. Feature is still useful, but it is not the delivery unit#

The word “feature” remains useful.

A feature is useful for talking about what the user sees:

One-shot transaction capture.

Underneath the feature, engineering is delivering a set of behaviors:

Feature: One-shot transaction capture

Behavior:
- understand a supported request
- preserve explicit user information
- expose ambiguity
- produce editable draft
- validate domain rules
- require confirmation
- persist once
- recover safely from failures

Each behavior has a quality envelope:

correctness
latency
safety
privacy
reliability
observability
cost
recoverability

The terms are distinct:

Feature = product surface.

Functional scope = situations the product supports.

Behavior = what the product should do in those situations.

Production commitment = the obligation to make that behavior dependable.

This distinction is especially useful for AI because “the feature exists” reveals little about whether it works well enough.