Build Your Own AgenticOS, Part 2: Shapers, The Intake Layer

Every vague request produces a vague output. The agent doesn't know who the reader is, what "done" looks like, or which of the five interpretations of your request you actually meant. It makes a reasonable guess and starts. Ten minutes later you have something that's technically responsive and completely wrong, and now you're editing instead of approving.

The shaper is the fix. A shaper is an intake agent whose only job is to turn a half-formed idea into a scoped brief before any execution agent touches a file. Not "clarify the request." Produce a structured document that removes all ambiguity for everything downstream. Intake quality is the ceiling on execution quality. A shaper enforces that ceiling before execution starts. Without one, every agent downstream simply inherits your ambiguity and confidently acts on it.

This is Part 2 of the Build Your Own AgenticOS series. If Part 1 covered the atomic unit (the skill file), Part 2 is about the layer that protects every skill from getting fired at the wrong target.

Here's what this post delivers:

• What a shaper does, and why it's distinct from the skill it feeds

• Why shapers come first in every request lifecycle

• The real routing logic from CLAUDE.md in this repo (which requests route to which shaper and how)

• How to write a shaper using the AskUserQuestion pattern

• When to skip the shaper entirely (the answer is narrower than you think)

• A starter shaper template you can copy today