🧗 belay

You climb. Claude holds the rope.

A Claude Code skill for people who build real software but aren't software developers — dentists, lawyers, founders, researchers, analysts. The safety layer for vibe coding.

In climbing, the belayer is the person holding your rope. They don't climb for you. They make sure a slip is never a fall.

npx skills add thanathe/belay · one command · no config · works immediately

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Why

You can build real things with Claude Code now without being a developer. That part works.

What doesn't work is what happens around the code: the confident "Done!" on something that was never run. The 200-line rewrite you can't review answering a 5-line request. The deploy that can't be rolled back because nothing was committed. The stack trace dumped in your lap. You are an expert — just in a different field. You'll catch a story that stops making sense; you won't catch an off-by-one in a diff. belay makes Claude act accordingly.

It doesn't teach you to code, and it doesn't slow Claude down with hand-holding. It changes how Claude behaves when the person across the table can't check its work.

The five rules

Once installed, Claude carries these through every coding session — you never invoke anything.

	Rule	Meaning
🪢	Snapshot before you change	Before touching anything that works, create the way back — and say what it is
✋	Confirm before anything irreversible	Deploys, deletes, live-database writes: what happens, who it touches, how to undo — then wait. And nothing ships uncommitted
🔬	Smallest change that solves it	A diff you can read is a safety property, not a style preference
👀	Verify — don't claim	"Done" requires an observation behind it: the page loaded, the test passed, the output says so
🗣️	Translate errors — never dump them	What it means, what caused it, what to do next. Raw trace below, for the record

And one meta-rule that outranks them: when Claude isn't sure, it says so in that sentence — because in this room, it's the only reviewer.

Before / after

Without belay	With belay
"Done! I've fixed the issue."	Ran it — here's the output, here's what still fails
Rewrites half the file	Changes 15 lines, mentions the other problems it saw
Deploys because you said "looks good"	"This goes live for real patients and can't be undone. Proceed?"
Patches a bug it never reproduced	Reproduces first — or says plainly that it can't
Pastes a stack trace	Three lines: meaning → cause → next step
Confidently wrong	"I think X, but I haven't verified it"

Install

Two prerequisites: Claude Code and git. Check git with git --version — if that prints a version, skip ahead. If not:

• macOS — running git --version offers to install the developer tools; say yes
• Windows — git-scm.com, accept every default
• Linux — sudo apt install git (or dnf on Fedora)

You don't need to know git — Claude runs it for you and explains as it goes. It just has to exist, because it's what makes "undo that" possible.

Then:

npx skills add thanathe/belay

That's the whole install. Restart Claude Code and it's on — Claude picks it up by itself on any coding task. To check: ask Claude "what skills do you have?" To call it explicitly: /belay.

npx skills add thanathe/belay -g   # everywhere, instead of just this project
npx skills update                  # update later
npx skills remove belay            # uninstall

_{No Node/npx? Plain git works the same: git clone https://github.com/thanathe/belay ~/.claude/skills/belay}

What's inside

SKILL.md                    the five rules — always on          🧗 on belay
references/debugging.md     something is broken                 🩺 reproduce → isolate → falsify
references/reviewing.md     "look this over first"              🔍 should it exist? does it do what it claims?
references/recovery.md      a change made things worse          🪂 stop, roll back, then think
references/git.md           no repo yet / git in the way        🪢 rope up, secrets stay out

The reference files load only when their moment comes, so the always-on part stays light.

What it is not

Not a lock. It's instructions Claude follows, not enforcement. For hard blocks (refusing rm -rf outright), use hooks — different layer, composes fine with this one.

Not project config. It has no opinion on your stack or your deploy process — those belong in your project's CLAUDE.md. belay is about how to work, not where.

Credit

Debugging discipline: the classic reproduce → isolate → falsify → cross-reference loop. Code-quality rules adapted from Karpathy's notes on where LLMs go wrong writing code.

MIT. Fork it and make it yours — it's prose; editing it is the point.

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"On belay?" — "Belay on." — "Climbing."