diff-analyze

diff-analyze is a skill for Claude Code, Codex from dyoshikawa/rulesync. It costs 21 tokens per session (221 once invoked), scanned A, original, MIT.

A workflow for comparing the current Git branch with origin/main, the main branch stored on a remote repository. It reviews the code changes, commit history, progress, risks, and follow-up work.

In plain words
What is it for?
Use it to refresh the main branch, inspect a branch's differences and commits, and prepare a practical progress summary.
Why use it?
It gives developers a concise picture of what a branch changes and whether the work appears complete or still has obvious gaps.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to refresh the main branch, inspect a branch's differences and commits, and prepare a practical progress summary.

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Install with agentmods
npx agentmods add skills/dyoshikawa/rulesync/diff-analyze
About the project

Rulesync is a command-line tool that generates configuration for different AI development tools from a shared set of rules. Developers use it to keep instructions, commands, MCP settings, ignore files, subagents, and skills consistent across coding agents. Catalogue skills support workflows built around Rulesync.

dyoshikawa/rulesync · 1,520 stars · on GitHub · rulesync.dyoshikawa.com

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.

Any agent
npx skills add dyoshikawa/rulesync --skill diff-analyze
Clone the repo
git clone --depth 1 https://github.com/dyoshikawa/rulesync

Made for: Claude Code, Codex.

Wrote 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.

agentmods badge for diff-analyze

README.md
[![agentmods](https://agentmods.dev/badge/skills/dyoshikawa/rulesync/diff-analyze/github.svg)](https://agentmods.dev/skills/dyoshikawa/rulesync/diff-analyze)
Your own site
<a href="https://agentmods.dev/skills/dyoshikawa/rulesync/diff-analyze"><img src="https://agentmods.dev/badge/skills/dyoshikawa/rulesync/diff-analyze/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.

agentmods 80×15 button for diff-analyze

Your own site · 80×15
<a href="https://agentmods.dev/skills/dyoshikawa/rulesync/diff-analyze"><img src="https://agentmods.dev/badge/skills/dyoshikawa/rulesync/diff-analyze.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 21 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 221 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 5.1 $0.00021 $0.00221
Opus 5.5 $0.00008 $0.00088
Sonnet 5.5 $0.00004 $0.00044
Haiku 4.5 $0.00002 $0.00022

Measured 1mo ago against content hash 50fdb5b31fd7, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

diff-analyze 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 1mo 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.

.rulesync/skills/diff-analyze/SKILL.md · 48 lines

What it actually says

Diff Analyze

Analyze the differences between the current branch and origin/main, and summarize the current work progress.

Step 1: Refresh Main Branch

Fetch the latest main branch state:

git fetch origin main

Step 2: Inspect the Diff

Get the differences between the current branch and main:

git diff origin/main...HEAD

Step 3: Inspect Commit History

Get the commit history of the current branch since it diverged from main:

git log origin/main..HEAD --oneline

Step 4: Summarize the Work

Based on the diff and commit history, summarize:

  • The main purpose of the current changes
  • The notable files or areas affected
  • The current implementation progress
  • Any obvious risks, gaps, or follow-up work

Keep the summary concise and practical.

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. 1mo ago First seen · 48 lines · 21 tokens per session scan A 50fdb5b31fd7

Subscribe to this mod's changes

diff-analyze is a skill published in the GitHub repository dyoshikawa/rulesync (1,520 stars, last pushed today), licensed MIT. It adds 21 tokens to every session and 221 once invoked, about $0.0001 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.