Gradle Library Source Reader Skill

This skill allows you to download and extract source JARs from Maven Central and other repositories to inspect library internals.

How It Works

Maven artifacts typically have a -sources.jar classifier that contains the original source code. This skill downloads and extracts these to ~/.extractlibs/src/<artifact>-<version>/ for inspection.

Usage

To download and extract library sources, run the following bash command:

# Format: group:artifact:version
~/.extractlibs/download-lib-sources.sh "io.ktor:ktor-client-core:3.3.2"

The script will:

1. Download the sources JAR from Maven Central (or other configured repos)
2. Extract it to ~/.extractlibs/src/<artifact>-<version>/
3. Report what was extracted

After Extraction

Once extracted, you can search and read the library source code:

# Find all Kotlin files
find ~/.extractlibs/src/ktor-client-core-3.3.2 -name "*.kt"

# Search for specific patterns
grep -r "suspend fun" ~/.extractlibs/src/ktor-client-core-3.3.2/

# Read specific files
cat ~/.extractlibs/src/ktor-client-core-3.3.2/io/ktor/client/HttpClient.kt

Common Libraries

Here are coordinates for common Kotlin/Java libraries:

Kotlin Standard Libraries

• org.jetbrains.kotlinx:kotlinx-coroutines-core:1.10.2
• org.jetbrains.kotlinx:kotlinx-serialization-json:1.9.0
• org.jetbrains.kotlinx:kotlinx-datetime:0.7.1
• org.jetbrains.kotlinx:kotlinx-io-core:0.8.0

Ktor

• io.ktor:ktor-client-core:3.3.2
• io.ktor:ktor-client-cio:3.3.2
• io.ktor:ktor-server-core:3.3.2
• io.ktor:ktor-server-netty:3.3.2

Databases

• org.mongodb:mongodb-driver-kotlin-coroutine:5.6.1
• org.jetbrains.exposed:exposed-core:0.61.0
• org.postgresql:postgresql:42.7.8

Caching

• io.lettuce:lettuce-core:6.7.1.RELEASE
• com.googlecode.xmemcached:xmemcached:2.4.8

AWS

• software.amazon.awssdk:s3:2.38.5
• software.amazon.awssdk:dynamodb:2.38.5

Other

• com.stripe:stripe-java:28.3.0
• com.google.firebase:firebase-admin:9.5.0

Troubleshooting

Sources not found: Not all libraries publish source JARs. This is common for:

• Very old libraries
• Some proprietary libraries
• Some Android-specific libraries

Wrong version: Make sure to specify the exact version. Use Maven Central to find available versions: https://search.maven.org/

Workflow Example

1. User asks about how Ktor's HttpClient handles retries
2. Download sources: ~/.extractlibs/download-lib-sources.sh "io.ktor:ktor-client-core:3.3.2"
3. Search for relevant code: grep -r "retry" ~/.extractlibs/src/ktor-client-core-3.3.2/
4. Read the specific files found
5. Explain to user based on actual source code