Claude Code Skills

Claude Code is an AI-powered CLI tool by Anthropic. This project includes custom skills (.claude/skills/) that teach Claude Code how to work with the SkyWalking Java Agent codebase.

Skills are reusable prompt templates that Claude Code can invoke via slash commands. They encode project-specific knowledge so that common development tasks can be performed consistently and correctly.

Available Skills

/new-plugin — Develop a New Plugin

Guides the full lifecycle of creating a new SkyWalking Java agent plugin:

  1. Gather requirements — target library, observation type (tracing/meter), span types
  2. Identify interception points — understand library usage, trace execution flow, choose classes/methods
  3. Create plugin module — directory structure, pom.xml, dependencies (provided scope)
  4. Implement instrumentation — V2 API, class matching (ByteBuddy), method matching
  5. Implement interceptors — ContextManager spans, ContextCarrier inject/extract, EnhancedInstance dynamic fields
  6. Register plugin — skywalking-plugin.def
  7. Write unit tests — TracingSegmentRunner, SegmentStorage
  8. Write E2E tests — Docker-based scenarios, expectedData.yaml
  9. Code style — checkstyle compliance, import restrictions
  10. Update documentation — Supported-list.md, CHANGES.md

Key principles encoded in this skill:

  • Always use V2 API (ClassEnhancePluginDefineV2, InstanceMethodsAroundInterceptorV2)
  • Never use .class references in instrumentation — always string literals
  • Never use reflection to access private fields — choose interception points with accessible data
  • Never use Maps to cache per-instance context — use EnhancedInstance.setSkyWalkingDynamicField()
  • Verify actual source code of target libraries — never speculate from version numbers
  • Span lifecycle APIs are ThreadLocal-based — create/stop in same thread unless async mode

/compile — Build the Project

Runs the appropriate build command based on what you need:

  • Full build with or without tests
  • Single module build
  • Checkstyle check
  • Plugin E2E test scenarios
  • Protobuf source generation for IDE setup

How to Use

  1. Install Claude Code
  2. Navigate to the skywalking-java repository root
  3. Run claude to start Claude Code
  4. Type /new-plugin or /compile to invoke a skill

Skills can also be triggered implicitly — when you describe a task that matches a skill’s purpose, Claude Code may suggest or invoke it automatically.

Project Context Files

In addition to skills, the project includes CLAUDE.md files that provide codebase context:

File Purpose
CLAUDE.md (root) Project overview, build system, architecture, conventions
apm-sniffer/apm-sdk-plugin/CLAUDE.md SDK plugin development guide (V2 API, class matching, testing)
apm-sniffer/bootstrap-plugins/CLAUDE.md Bootstrap plugin specifics (JDK class instrumentation)

These files are automatically loaded by Claude Code when working in the repository, providing it with the knowledge needed to assist with development tasks.