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.
npx skills add nicknisi/claude-plugins --skill explain-diffgit clone --depth 1 https://github.com/nicknisi/claude-pluginsWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/skills/nicknisi/claude-plugins/explain-diff)<a href="https://agentmods.dev/skills/nicknisi/claude-plugins/explain-diff"><img src="https://agentmods.dev/badge/skills/nicknisi/claude-plugins/explain-diff/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/nicknisi/claude-plugins/explain-diff"><img src="https://agentmods.dev/badge/skills/nicknisi/claude-plugins/explain-diff.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00118 | $0.00910 |
| Opus 5.5 | $0.00047 | $0.00364 |
| Sonnet 5.5 | $0.00024 | $0.00182 |
| Haiku 4.5 | $0.00012 | $0.00091 |
Grade A, and why
explain-diff 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 2mo 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.
How it starts
The opening of the file, as written. The whole thing — 62 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Explain Diff
Create a rich, interactive HTML explanation of a code change. The reader may be a teammate encountering the codebase for the first time or the author checking their own understanding — the document should serve both.
Resolve the change
Pin down exactly what to explain before writing anything:
- PR number or URL —
gh pr diff <number>for the diff,gh pr view <number>for the title, description, and discussion - Branch —
git diff <base>...<branch>against the repo's default branch - Commit —
git show <sha> - Nothing specified — the working tree (
git diff HEAD); if clean, the current branch against the default branch
Then explore beyond the diff: read the touched files in full, their callers, and the subsystem they belong to. The Background section lives or dies on your understanding of the surrounding system, not just the delta.
Sections
The explanation has four sections, in this order:
-
Background — Explain the existing system this change slots into. The reader's familiarity is unknown, so layer it: a deep background for beginners (marked as skippable for readers who already know the system), then a narrower background directly relevant to the change.
-
Intuition — Explain the core idea of the change: what problem existed, what insight the change embodies, why this approach. Focus on the essence, not the full details. Use concrete examples with toy data, and use figures and diagrams liberally.
-
Code — A high-level walkthrough of the changes. Group and order them for understanding — by concept or data flow — not by file order in the diff.
-
Quiz — Five interactive multiple-choice questions testing whether the reader understood the substance. Medium difficulty: answerable only by someone who actually understood the change, but no gotchas. On click, reveal whether the answer was correct with a short explanation either way — the feedback is where the learning happens.
Output format
Produce a single self-contained HTML file:
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.
- 2mo ago First seen · 62 lines · 118 tokens per session scan A c6091568576c
explain-diff is a skill published in the GitHub repository nicknisi/claude-plugins (114 stars, last pushed 2mo ago), licensed MIT. It adds 118 tokens to every session and 910 once invoked, about $0.0005 per session on Opus 5.5. 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 2026-08-30.
explain-diff compared with skills from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| explain-diffnicknisi/claude-plugins | Skill | 114 | 2mo ago | MIT | A | 118 | Claude Code |
| hr-onboardingnexu-io/open-design | Skill | 106k | today | Apache-2.0 | A | 62 | Claude Code, Codex |
| book-mirrorgarrytan/gbrain | Skill | 32k | today | MIT | A | 138 | Claude Code |
| exam-forecastanthropics/claude-for-legal | Skill | 9.9k | today | Apache-2.0 | A | 73 | Claude Code |
| lean-formalizewanshuiyin/Auto-claude-code-research-in-sleep | Skill | 19k | yesterday | MIT | A | 81 | Claude Code |
| eli5companion-inc/feynman | Skill | 10k | 6d ago | MIT | A | 63 | Claude Code, Codex |
| deck-course-modulenexu-io/html-anything | Skill | 9.4k | yesterday | Apache-2.0 | A | 25 | Claude Code, Codex |