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Diffuse-Native-Apps: Skill for Claude Code

.agents/skills/diff-engine/SKILL.md

diff-engine is a skill for Claude Code, Codex from hoangsonww/Diffuse-Native-Apps. It costs 38 tokens per session (245 once invoked), scanned A, original, MIT.

A set of rules for maintaining a system that compares two sets of collected data and groups related changes over time. It covers how values are matched, classified by severity, and tested.

In plain words
What is it for?
Use it when changing comparison rules, change severity, identity matching, or time-based change grouping in the Diffuse project.
Why use it?
It helps prevent incorrect reports of added, removed, or changed data when the comparison logic is updated. It also keeps comparison behavior consistent across different data types.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: installed under .agents/ (shared by several agents).

This is hoangsonww/Diffuse-Native-Apps's own configuration. It tells Claude Code and Codex how to work on Diffuse-Native-Apps itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything Diffuse-Native-Apps configures →

not rated 11repo 1mo ago A scan 38 tokens original MIT
View source ↗ hoangsonww/Diffuse-Native-Apps hoangsonww.github.io
Reuse

Borrowing it

Nothing to install: this file belongs to hoangsonww/Diffuse-Native-Apps. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/hoangsonww/Diffuse-Native-Apps/master/.agents/skills/diff-engine/SKILL.md
Clone the repo
git clone --depth 1 https://github.com/hoangsonww/Diffuse-Native-Apps

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-engine

README.md
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Your own site
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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-engine

Your own site · 80×15
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Per session 38 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 245 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.
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 $0.00038 $0.00245
Opus 5.5 $0.00015 $0.00098
Sonnet 5.5 $0.00008 $0.00049
Haiku 4.5 $0.00004 $0.00024

Measured yesterday against content hash 881a12ba08e1, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

diff-engine 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 yesterday.

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.

.agents/skills/diff-engine/SKILL.md · 19 lines

What it actually says

Diff engine

The engine is generic. Capabilities declare ComparisonRule and ChangeSeverity on property descriptors. Do not add if capability == .docker branches.

  • ValueComparator is the only place two readings are judged "the same".
  • Identity matching is EntityIdentity (normalized value + kind + optional scope). Path identities use EntityIdentity.path.
  • diff(A, A) is empty. Reverse diffs swap added/removed counts. Property tests in Packages/DiffuseDiff/Tests and Tests/Invariants guard this.
  • Severity can escalate on a major version jump; do not special-case tools by name.
  • Correlation (ChangeCorrelator) groups by time window, not by inference.

Read Documentation/DiffEngine.md and Documentation/adr/0003-schema-driven-diff.md.

After changes: swift test --filter DiffuseDiffTests and swift test --filter DiffuseInvariantTests.

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. yesterday First seen · 19 lines · 38 tokens per session scan A 881a12ba08e1

Subscribe to this mod's changes

diff-engine is a skill published in the GitHub repository hoangsonww/Diffuse-Native-Apps (11 stars, last pushed 1mo ago), licensed MIT. It adds 38 tokens to every session and 245 once invoked, about $0.0002 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 2026-11-07.

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Related

diff-engine compared with skills from other repositories

diff-engine next to 6 skills from other repositories
ModTypeStarsLast pushLicenceScanTokensWorks with
diff-enginehoangsonww/Diffuse-Native-AppsSkill111mo agoMITA38Claude Code, Codex
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argent-react-native-optimizationsoftware-mansion/argentSkill3.2ktodayApache-2.0A71Claude Code, Codex
argent-metro-debuggersoftware-mansion/argentSkill3.2ktodayApache-2.0A104Claude Code, Codex
argent-native-profilersoftware-mansion/argentSkill3.2ktodayApache-2.0A37Claude Code, Codex
compose-performancechrisbanes/skillsSkill1.1k2d agoApache-2.0A42Claude Code