Start with the problem, not the extension

Claude Code extensions do not replace a task specification, context management, evidence, Git, diff review, or human decisions. They are useful when a repeatable process needs to become more stable, explicit, and portable.

Before choosing a mechanism, classify the need: one-off prompt, project-wide rule, scoped constraint, repeatable workflow, isolated research, external integration, event reaction, or team distribution.

MechanismUse it when
PromptThe action is one-off or still being explored
CLAUDE.mdThe rule applies across the repository
RuleThe constraint applies to a specific path or area
SkillThe procedure repeats with a defined result
SubagentA bounded investigation benefits from a separate context
MCPThe workflow needs controlled external data or actions
HookA predictable event should trigger a local response
PluginA validated workflow must be distributed

Choose the narrowest scope

  1. Keep a one-off action in the prompt.
  2. Record repository-wide commands and architecture rules in CLAUDE.md.
  3. Use a scoped rule for a requirement limited to paths such as payments/** or docs/**.
  4. Package recurring issue analysis or review as a skill.
  5. Delegate broad research to a subagent when it would overload the main session.
  6. Use MCP only when the required data is outside the repository.
  7. Use a hook for a small, predictable event reaction.
  8. Consider a plugin only after the workflow is stable and team-ready.

Extension map

Conceptual Workflow Kit layout
workflow-kit/
└── .claude/
    ├── CLAUDE.md
    ├── rules/
    ├── skills/
    ├── agents/
    ├── hooks/
    └── mcp/

Example: issue workflow

  1. Read the issue and record the goal, scope, non-goals, and acceptance criteria.
  2. Define verification and identify risks before editing.
  3. List candidate affected files and confirm them through discovery.
  4. Do not change code before the plan and evidence boundary are clear.
  5. After implementation, inspect the diff, checks, and review findings.

Scope warnings

  • Do not move a local rule into global CLAUDE.md.
  • Do not create a scoped rule for a repository-wide requirement.
  • Do not create a hook without predictable boundaries and a kill switch.
  • Do not package a one-off experiment as a plugin.
  • Use narrower controls and regression evidence for sensitive areas.

Canonical lesson source · JavaRush

Open JavaRush material