Sharpen /scalable grounding: per-claim, not per-session; do the cheap check yourself

[pallaoro]

Why

A coding agent running /scalable on a dashboard routing change read every worker around apps/web — app-router, website-supervisor, tunnel-auth, cloudflare.ts — then ruled by transferring that architecture onto the dashboard by analogy, never opening the one file the change actually routes through (apps/web/wrangler.jsonc). Its own postmortem:

Grounding is per-claim, not per-session. I'd verified four neighboring workers … and that volume of grounding made the one load-bearing, unverified claim feel as solid as the rest. … The prior that bit me was one I minted this session from neighboring code. Those are more dangerous than training priors, because they feel freshly earned.

The cheap, decisive check was one file, seconds away — and instead of doing it, I ended my message asking the human to confirm. That's deferring verification instead of doing it.

The skill already said "Read the actual code and architecture this touches before ruling." The gap was framing, not a missing rule — so this sharpens the existing "Ground it first" block rather than adding a new section.

What changed (commands/scalable.md only)

• Reframe "priors" — a prior isn't only stale training data, it's also a conclusion minted this session from neighboring code; the latter is more dangerous because it feels freshly earned and rides on the credibility of everything else you verified.
• New bullet — ground per claim, not per session: isolate the single load-bearing claim and verify that one directly; "built like its neighbors" is not evidence about the thing it touches.
• New bullet — do the cheapest decisive check yourself: if one file settles the load-bearing claim, open it; don't end your turn asking the human to confirm what a readable file answers.
• Extended the existing "read the actual code" bullet to call out the exact file the change runs through, not only its neighbors.

No generated/mirror files touched — build-rules.js fans out CLAUDE.md, not commands/scalable.md; node scripts/build-rules.js --check passes.

🤖 Generated with Claude Code