# Kotlin Tooling Agp9 Migration

Migrates Kotlin Multiplatform (KMP) projects to Android Gradle Plugin 9.0+.

- Repository: https://github.com/Kotlin/kotlin-agent-skills (1104 stars)
- Category: Mobile
- License: Apache-2.0
- Last updated: 2026-10-30
- Runs scripts: yes, review before use

## Install

Claude Code: `npx skills add Kotlin/kotlin-agent-skills --skill kotlin-tooling-agp9-migration -g -a claude-code -y`
Codex: `npx skills add Kotlin/kotlin-agent-skills --skill kotlin-tooling-agp9-migration -g -a codex -y`
Cursor: `npx skills add Kotlin/kotlin-agent-skills --skill kotlin-tooling-agp9-migration -g -a cursor -y`
Gemini CLI: `npx skills add Kotlin/kotlin-agent-skills --skill kotlin-tooling-agp9-migration -g -a gemini-cli -y`
Claude Code plugin marketplace: `/plugin marketplace add Kotlin/kotlin-agent-skills`

## Description

Migrates Kotlin Multiplatform (KMP) projects to Android Gradle Plugin 9.0+. Handles plugin replacement (com.android.kotlin.multiplatform.library), module splitting, DSL migration, and the new default project structure. Use when upgrading AGP, when build fails due to KMP+AGP incompatibility, or when the user mentions AGP 9.0, android multiplatform plugin, KMP migration, or com.android.kotlin.multiplatform.library.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# KMP AGP 9.0 Migration

Android Gradle Plugin 9.0 makes the Android application and library plugins incompatible
with the Kotlin Multiplatform plugin in the same module. This skill guides you through the
migration.

## Step 0: Analyze the Project

Before making any changes, understand the project structure:
1. Read `settings.gradle.kts` (or `.gradle`) to find all modules
2. For each module, read its `build.gradle.kts` to identify which plugins are applied
3. Check if the project uses a Gradle version catalog (`gradle/libs.versions.toml`). If it exists,
   read it for current AGP/Gradle/Kotlin versions. If not, find versions directly in `build.gradle.kts`
   files (typically in the root `buildscript {}` or `plugins {}` block). **Adapt all examples in this
   guide accordingly**, version catalog examples use `alias(libs.plugins.xxx)` while direct usage
   uses `id("plugin.id") version "x.y.z"`
4. Read `gradle/wrapper/gradle-wrapper.properties` for the Gradle version
5. Check `gradle.properties` for any existing workarounds (`android.enableLegacyVariantApi`)
6. Check for `org.jetbrains.kotlin.android` plugin usage, AGP 9.0 has built-in Kotlin and this plugin must be removed
7. Check for `org.jetbrains.kotlin.kapt` plugin usage, incompatible with built-in Kotlin, must migrate to KSP or `com.android.legacy-kapt`
8. Check for third-party plugins that may be incompatible with AGP 9.0 (see "Plugin Compatibility" section below)

If Bash is available, run `scripts/analyze-project.sh` from this skill's directory to get a structured summary.

### Classify Each Module

For each module, determine its type:

The rest: https://github.com/Kotlin/kotlin-agent-skills/blob/HEAD/skills/kotlin-tooling-agp9-migration/SKILL.md