r8-analyzer

name	r8-analyzer
description	Analyzes Android build files and R8 keep rules to identify redundancies, broad package-wide rules, and rules that subsume library consumer keep rules. Use when developers want to optimize their app's size, remove redundant or overly broad keep rules, or troubleshoot Proguard configurations.
license	Complete terms in LICENSE.txt
metadata	{"author":"Google LLC","last-updated":"2026-06-09","keywords":["R8","proguard","keep rules","app size","optimization"]}

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 < 9.0, suggest migration to 9.0 for build time improvement performance
• Full Mode : Verify android.enableR8.fullMode=false is removed from gradle.properties.

Step 2. Analysis path selection

• Inspect build.gradle, build.gradle.kts, and gradle.properties and libs.versions.toml to get the R8 version

• If R8 >= 9.3.7-dev : Proceed to Path A (Quantitative).

• If R8 < 9.3.7-dev : Proceed to Path B (Heuristic).

Path A: Quantitative data generation (R8 >= 9.3.7-dev)

• Check requirements : Python and protobuf package are mandatory.
• Generate and analyze : You MUST run the shell commands described in references/CONFIGURATION-ANALYZER.md to generate the proto file using R8 configuration analyzer, convert it to json and analyze the result.
• Report : Rely entirely on the generated file analysis.txt for scores and rule impact metrics. Proceed to Step 3.

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

(Use ONLY if quantitative data generation is not possible)

• Manual evaluation : Inspect proguard-rules.pro.
• Library check : Compare rules against references/REDUNDANT-RULES.md. Suggest Remove for bundled rules.
• 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).
• Validation : Suggest Macrobenchmark tests using UI Automator for any proposed changes. Proceed to Step 3.

Step 3. Report generation

• Format : Follow references/REPORT_FORMAT.md strictly.
• Input: Extract metrics (Scores, Impacts, Example Classes) directly from generated file analysis.txt if using Path A, or from manual findings if using Path B.
• Output : Output ONLY the raw Markdown report in the chat. Do NOT output conversational filler (for example, "Here is your report..."). Do NOT provide recommendations, next steps, or any other text outside of the sections defined in references/REPORT_FORMAT.md Do NOT mention the path used for analysis of the configuration

Constraints

• Strict output limit: The final output MUST strictly be the Markdown report and nothing else.
• No code changes: Research and suggest only; Do not modify files.
• No redundancy: Do not explain R8 benefits or reference skill internal files in the report.
• Focus: Omit sections (for example, Subsumed Rules, Configuration) if no issues or items are found.