expose-tunable-knob

# Expose Tunable Knob An agent iterating on a **perceptual** parameter — a mask's size, a color threshold, an animation's timing, an audio gain — hits a hard wall the moment it can't render, watch, or listen to its own output. A human running a live webcam feed, a rendered UI, or a mixed audio track can judge instantly whether a value looks or sounds right; the agent, reasoning purely from code and possibly one static screenshot, cannot. The naive move — pick a value from domain reasoning, ship it, wait for feedback, repeat — burns a full rebuild/re-run/re-report round-trip **per guess**, and the agent's guess still carries no more information than the human's own eyes would supply directly. ## When to Use This Skill | Use this skill when... | Skip when... | |---|---| | Tuning a value whose correctness is judged by a sense the agent lacks (sight, sound, feel) | The value has an objective, computable correctness criterion (a test asserts the exact number) | | The user has already pushed back once on a guessed default ("that's better, but...") | This is the first attempt — try a principled default before adding a knob | | The parameter is genuinely continuous/subjective (position, size, gain, ratio, threshold) | The parameter is binary/structural (a feature flag, an algorithm choice) — that's a decision, not a tuning value | | The runtime already has (or can cheaply gain) a live control surface — a GUI slider, a config‑reload flag, a CLI `--watch` | Changing the value requir...