An Android build-analysis guide for reviewing R8 configuration and ProGuard keep rules. R8 is Android's code shrinking and optimization tool; keep rules tell it which code must not be removed or changed.

Use it to inspect Gradle files and keep rules, find rules that overlap or replace library rules, troubleshoot ProGuard configuration, and reduce unnecessary Android app size.

It identifies duplicate, overly broad, or unnecessary rules that can make an app larger or complicate its build configuration. It also chooses an analysis method based on the Android Gradle Plugin and R8 versions.

r8-analyzer — Skill for Claude Code by hanamizuki

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 hanamizuki/solopreneur --skill r8-analyzer

Clone the repo

git clone --depth 1 https://github.com/hanamizuki/solopreneur

Made for: Claude Code.

Or install android-dev, the plugin that ships this one along with the rest of its 36 skills, 1 agent.

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/hanamizuki/solopreneur/r8-analyzer/github.svg)](https://agentmods.dev/skills/hanamizuki/solopreneur/r8-analyzer)

Your own site

<a href="https://agentmods.dev/skills/hanamizuki/solopreneur/r8-analyzer"><img src="https://agentmods.dev/badge/skills/hanamizuki/solopreneur/r8-analyzer/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/hanamizuki/solopreneur/r8-analyzer"><img src="https://agentmods.dev/badge/skills/hanamizuki/solopreneur/r8-analyzer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 60 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,077 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.

Model	Per session	Once invoked
Fable 5.1	$0.00060	$0.01077
Opus 5	$0.00030	$0.00539
Sonnet 5	$0.00012	$0.00215
Haiku 4.5	$0.00006	$0.00108

Measured 11d ago against content hash 9d16c9112f8c, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

r8-analyzer 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 11d 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.

plugins/claude/android-dev/skills/r8-analyzer/SKILL.md · 67 lines

How it starts

The opening of the file, as written. The whole thing — 67 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Step 1. Setup and configuration check

Inspect build.gradle, build.gradle.kts, and gradle.properties.
Use references/CONFIGURATION.md to identify missing optimizations.
AGP : If version is lower than 9.0, suggest migration to 9.0 for build-time performance improvement.
Full Mode : Verify android.enableR8.fullMode=false is removed from gradle.properties.

Step 2. Analysis path selection

Inspect build.gradle, build.gradle.kts, gradle.properties, libs.versions.toml, and the top-level settings.gradle or settings.gradle.kts to get the AGP and R8 versions. An explicit com.android.tools:r8 version in the settings file overrides the version embedded in AGP.
If AGP >= 9.3.0 : Proceed to Path A (Standalone Task).
If AGP < 9.3.0 and R8 >= 9.3.7-dev : Proceed to Path B (Quantitative).
If none of the conditions are met, proceed to Path C (Heuristic).

Path A: Standalone Gradle task (AGP >= 9.3.0)

Step 1: Run standalone task : Run ./gradlew :app:analyzeReleaseR8Config to evaluate the R8 configuration. You MUST wait for this command to finish before proceeding.
Step 2: Analyze : Read the generated HTML report at app/build/reports/r8/r8-config-analyzer-release.html for scores and rule impact metrics.

Path B: Quantitative data generation (R8 >= 9.3.7-dev and AGP < 9.3.0)

Step 1: Generate report : Run mkdir -p "$PWD/tmp/r8analysis" && ./gradlew assembleRelease -Dcom.android.tools.r8.dumpkeepradiushtmltodirectory="$PWD/tmp/r8analysis". You MUST wait for this command to finish before proceeding.
Step 2: Analyze : Read the generated HTML report in tmp/r8analysis/ for scores and rule impact metrics.

Path C: Heuristic evaluation and recommendation (R8 < 9.3.7-dev)

(Use ONLY if quantitative data generation is not possible)

Step 1: Manual evaluation : Inspect proguard-rules.pro.
Step 2: Library check : Compare rules against references/REDUNDANT-RULES.md. Suggest Remove for bundled rules.
Step 3: Custom rule check : Use references/KEEP-RULES-IMPACT-HIERARCHY.md and references/REFLECTION-GUIDE.md to prioritize and evaluate. Suggest Refine for broad rules (for example, package-wide).
Step 4: Validation : Suggest Macrobenchmark tests using UI Automator for any proposed changes. Proceed to Step 3.

Read the full file on GitHub · 67 lines

Files

What ships with it

9 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.

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.

11d ago First seen · 67 lines · 60 tokens per session scan A 9d16c9112f8c

Subscribe to this mod's changes

r8-analyzer is a skill published in the GitHub repository hanamizuki/solopreneur (148 stars, last pushed 25d ago), licensed MIT. It adds 60 tokens to every session and 1,077 once invoked, about $0.0003 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 2026-08-30.

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