Decision Matrix: Rules vs. MCP vs. Skills vs. Workflows
| Capability Type | What it is | Best For… | Trigger |
|---|---|---|---|
| Rules | Guardrails & Constraints | Coding standards, linting rules, naming conventions. | Always On (or by file type) |
| MCP Servers | Hands & External Data | Reading a DB, fetching live docs, searching GitHub. | On-Demand (as needed) |
| Agentic Skills | Specialized Methodology | Complex migrations, boilerplate scaffolding, multi-step validation. | Agent-Triggered (Semantic Match) |
| Workflows | Automation Macros | /deploy, /test-all, /onboard-project. | User-Triggered (Slash command) |
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“I want the agent to NEVER use
anyin TypeScript.”- 👉 Use a Rule. It’s a persistent constraint.
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“I want the agent to be able to search the latest shadcn documentation online.”
- 👉 Use an MCP Server. It connects the agent to a live, external data source.
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“I want the agent to follow a specific 5-step process to generate a New Feature module.”
- 👉 Use a Agentic Skills. It provides a modular “how-to” that includes templates and scripts.
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“I want to type
/shipand have the agent run tests, lint, and push to main.”- 👉 Use a Workflow. It’s a user-initiated macro for a predictable sequence.
Pro-Tip: The “Consultant” Analogy
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Rules: The corporate policy manual (Must follow).
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MCP: The library and internet access (Information source).
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Skills: The specialist training (How to do a specific job).
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Workflows: The scheduled agenda (What to do right now).