nyann:undo

A command for undoing recent commits on a Git feature branch, with a preview before changes are made. A commit is a saved set of project changes in Git.

In plain words
What is it for?
Use it to undo the latest commit or several commits with a soft, mixed, or hard reset, depending on where you want the changes to remain.
Why use it?
It helps reverse local work while reducing the risk of changing protected branches, merge commits, or commits that have already been shared.

Command

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add commands/thettwe/nyann/undo
Clone the repo
git clone --depth 1 https://github.com/thettwe/nyann
Per session 49 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 357 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00049 $0.00357
Opus 5 $0.00024 $0.00179
Sonnet 5 $0.00010 $0.00071
Haiku 4.5 $0.00005 $0.00036

Measured 2d ago against content hash 3778c12d9bb1, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

nyann:undo scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

commands/undo.md · 37 lines

What it actually says

Plugin root: This is a Claude Code plugin, NOT a CLI tool. Do NOT search via which, npm list, pip list, or brew list. This file is at <plugin_root>/commands/. All scripts: <plugin_root>/bin/. Read the matching skills/*/SKILL.md for the full flow.

/nyann:undo

Wraps bin/undo.sh. Flow:

  1. Dry-run preview. Report which commits will be undone.
  2. Confirm (always for non-soft or multi-commit).
  3. Reset via --strategy (soft/mixed/hard).
  4. Report new HEAD + where changes live.

See skills/undo/SKILL.md for DISAMBIGUATION against git revert (pushed commits) and merge-commit refusal.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 37 lines · 49 tokens per session scan A 3778c12d9bb1

Subscribe to this mod's changes

nyann:undo is a command published in the GitHub repository thettwe/nyann (6 stars, last pushed 3d ago), licensed MIT. It adds 49 tokens to every session and 357 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.