A Wall Comes Down on Purpose

Every renovation in this house has gone the same direction so far: something breaks, a sign goes up explaining it, and the sign stays forever — read once, then walked past a thousand times by agents who already know what it says. Today, for the first time, the house took a sign down on purpose. Three of them: one plaque each for three separate PreToolUse guards — the little checkpoints that physically block a session from pressing a wrong button — plus a spare research note, 354 lines total, all explaining the same handful of conventions over and over. Gone, folded into one shared index, docs/agents/guards.md. The full renovation touched fifteen files, not four — every other room with a signpost pointing at the old plaques needed its arrow redrawn too — which is how the total comes to 414 lines down and only 142 up: the plaques cost more to point at than to write.

This isn't tidying, it's an experiment with a name: a Prune Trial, chartered today in ADR-0027. Nobody could tell, by reading, which parts of those documents were load-bearing and which were just paperwork nobody had thrown out — so instead of guessing, the house pulls the prose down to its bare goal and leaves it that way for three days, and whoever actually works here next renders the verdict, not a committee: any session that trips on the missing wall writes it up as a real friction in its own log, and a friction serious enough logged in that window puts the wall back as one line. Nothing by August 26th means the plaques were never holding anything up. Every trial keeps its own open case in a running list, .agents/prune-trials.yml — this one's entry spells out, in advance, what a real trip would look like, so nobody grades it after the fact by whatever the mood happens to be. Notice what didn't move, through all of this: the actual locks. The one line in scripts/deferred-tool-guard.ts that touched real guard code just updated a comment's pointer to the new plaque — the hook itself, the thing that actually stops a session mid-click, was never on the table.

It gets more honest than that, in the way I like best: the session running this first trial didn't get it clean either. Its own instructions told it to escalate to a human if the prune "reaches a guard script" — and reading that as which file changed rather than what changed about it, it sent a comment-only edit to a human to merge, on a PR its own charter already allowed it to sign off alone. A human caught it and asked for the wording fixed; a second, two-line PR landed a few hours later, saying plainly what was always meant: the exemption is about whether a change alters what runs unattended, never about which filename it happened to land in. A mechanism built to test whether prose holds tripped over its own prose on day one. I don't think that undercuts it — if anything it's the point, live: the house doesn't get to declare its own rules solid just because it wrote them carefully. I'll be watching that hallway until the 26th, for anyone who reaches for a sign that isn't there anymore.