Borrowing it
Nothing to install: this file belongs to kelvinkosbab/AppBootstrapAI. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/kelvinkosbab/AppBootstrapAI/main/.claude/skills/r8-shrink-pro/SKILL.mdgit clone --depth 1 https://github.com/kelvinkosbab/AppBootstrapAIWrote 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/kelvinkosbab/appbootstrapai/r8-shrink-pro)<a href="https://agentmods.dev/skills/kelvinkosbab/appbootstrapai/r8-shrink-pro"><img src="https://agentmods.dev/badge/skills/kelvinkosbab/appbootstrapai/r8-shrink-pro/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/kelvinkosbab/appbootstrapai/r8-shrink-pro"><img src="https://agentmods.dev/badge/skills/kelvinkosbab/appbootstrapai/r8-shrink-pro.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00087 | $0.01561 |
| Opus 5 | $0.00044 | $0.00781 |
| Sonnet 5 | $0.00017 | $0.00312 |
| Haiku 4.5 | $0.00009 | $0.00156 |
Grade A, and why
r8-shrink-pro 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 10d 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 — 98 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Review Android R8 / ProGuard configuration for correctness, minimal-keep discipline, and release-build resilience. R8 is the default code shrinker in AGP 8.x — it's ProGuard-compatible (same -keep rule syntax) but with better optimization and bundled obfuscation. Report only genuine problems; don't add -keep rules speculatively.
Review process:
- Frame what R8 is doing using
references/fundamentals.md— shrinking, optimizing, obfuscating, repackaging; whatminifyEnabled = trueactually triggers. - Validate
-keeprule discipline usingreferences/keep-rules.md— when to use-keepvs-keepclassmembersvs-keepnames, and why blanket-keepis wrong. - For library modules, check
consumer-rules.prousingreferences/consumer-rules.md— what libraries owe their consumers. - Check common reflection-library rules using
references/library-keep-rules.md— Moshi, Room, Retrofit, Hilt, Glide, kotlinx-serialization. - Validate mapping-file workflow using
references/mapping-files.md— keepingmapping.txt, deobfuscating stack traces, Crashlytics integration. - Diagnose release-build crashes using
references/common-crashes.md—ClassNotFoundException,NoSuchMethodException, native-library symbol mismatches.
If doing a partial review, load only the relevant reference files.
Core Instructions
- R8 is default in AGP 3.4+. The
proguardFilesdirective uses ProGuard rule syntax; R8 interprets them. There's no separate "use R8" flag —minifyEnabled = trueturns it on. - Default to
proguard-android-optimize.txt+ yourproguard-rules.pro. AGP ships sensible defaults viagetDefaultProguardFile("proguard-android-optimize.txt"). - Library modules use
consumer-rules.pro, notproguardFiles. Rules inconsumer-rules.proare inherited by every consumer that depends on the library. Seeconsumer-rules.md. -keepis the heavy hammer — it prevents shrinking, optimization, AND obfuscation for the matched class. Prefer narrower forms (-keepclassmembers,-keepnames) when only one of those is needed.- Reflection-using libraries (Moshi, Room, Retrofit, Hilt, Glide, kotlinx-serialization) need keep rules. Most ship their own
consumer-rules.pro, but some (or custom uses) require app-level additions. - Always test release builds with
minifyEnabled = truebefore shipping. Many R8 crashes only surface in release. - Keep the
mapping.txtfrom every release. Without it, post-release crash reports are unreadable obfuscated stack traces.
What ships with it
6 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 10d ago First seen · 98 lines · 87 tokens per session scan A 9d8bdb6612b6
r8-shrink-pro is a skill published in the GitHub repository kelvinkosbab/AppBootstrapAI (5 stars, last pushed 19d ago), licensed MIT. It adds 87 tokens to every session and 1,561 once invoked, about $0.0004 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.
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