Comparison Table
| Mechanism | Scope | Invocation | Resources | Use Case |
|---|---|---|---|---|
| Skill (user) | Codified workflow | /name (user) | Yes | Repeatable task triggered manually |
| Skill (auto) | Reusable knowledge | Auto by model | Yes | Shared expertise across agents |
| Plugin | Marketplace | Global | Yes | Third-party integration |
| Agent | Autonomous specialist | Task tool | Via memory | Complex delegation |
CC 2.1.3:
.claude/commands/is merged into.claude/skills/. Adddisable-model-invocation: truefor user-triggered-only skills.
User-Invocable Skills (formerly “Commands”)
Since CC 2.1.3, manually triggered workflows live in .claude/skills/ with disable-model-invocation: true.
# .claude/skills/release/SKILL.md---name: releasedescription: Prepare a release (bump version, CHANGELOG, tag)allowed-tools: [Read, Write, Bash]disable-model-invocation: true---1. Read current version from package.json2. Bump according to semver (patch/minor/major)3. Update CHANGELOG.md4. Create git tagWhen to choose: You have a sequence of instructions you trigger intentionally several times a week.
Model-Invocable Skills
A skill without disable-model-invocation is loaded automatically by the model when the description matches the context.
# .claude/skills/security-guardian/SKILL.md---name: security-guardiandescription: OWASP security review -- use when reviewing auth, routes, or user inputallowed-tools: [Read, Grep, Glob]---Analyze code for OWASP Top 10 vulnerabilities...When to choose: Multiple agents need the same specialized knowledge, or you want Claude to automatically load the right expertise.
Plugins: Third-Party Integrations
Plugins come from the marketplace and add external capabilities. Install via /plugin marketplace add.
When to choose: An existing third-party integration covers exactly your need.
${CLAUDE_PLUGIN_DATA} (v2.1.78+): Persistent directory for storing state between sessions.
Agents: Complex Task Delegation
An agent is a specialized Claude with its own tools and scope. It isolates context, not simulates a human role.
---name: security-auditmodel: opustools: Read, Grep, Glob---Analyze code for OWASP vulnerabilities...When to choose: A long task that would pollute the main context, or parallelizable work.
Quick Decision Rule
Manually triggered workflow = User-invocable Skill. Knowledge to share across agents = Model-invocable Skill. Third-party integration = Plugin. Task to delegate with isolated context = Agent.
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