harness-door-patternlisted

# The Harness Door Pattern A **door** boots a harness into a chosen posture. Five have been built. The work is the same shape every time, and most of the cost is in the probe, not the code. This skill exists so door six is cheap. --- ## The core insight **Every harness hides its skills somewhere different, but there are only about four places.** Identify which class you are dealing with and you have most of the answer. Guess wrong and you will burn a probe campaign proving a flag does nothing. ### Class 1 — Allowlist flags that read like suppression flags The flag takes a list of scopes to **load**. Naming a scope *keeps it alive*. The instinct to "name the thing you want to suppress" is exactly backwards, and it looks correct in a diff. | harness | flag | the trap | |---|---|---| | claude | `--setting-sources` | naming `project` **keeps** project-scope skills. Empty string is the suppression. | | hermes | `--toolsets` | naming a set that omits `skills` is what drops the skill index. | This class has bitten twice in this repo — KC4 on `curated`, then P8 on `product-floor` (#24), which shipped with the same defect for a month because the fix was applied to one posture and not its sibling. **When you fix an allowlist, grep for every other posture using the same flag.** ### Class 2 — Native evict / readmit The harness has a real primitive: one flag clears skills, another admits specific ones. Cleanest class to build against; a curated posture falls out almost for free