How prompts, instructions, Skills and MCP fit together

Map the parts to their jobs

Do not add every layer just because the terms exist. A small task may need only a clear request. Introduce reusable instructions or a connection when there is a concrete repeated need.

Follow one task through the layers

For a project-update deck, your prompt supplies the audience and reporting period. Project instructions define where files belong. A deck Skill describes the sequence for making the artifact. An authorized tool can retrieve status information if you choose to connect it.

Use the supplied brief as the source of truth.
If the project-board connection is available, retrieve only the named project.
Apply the selected deck method.
List missing evidence before generating the final export.

Fix the missing layer

• The result is vague: improve the task brief and source material.
• The same project convention is repeatedly missed: review project instructions.
• A repeated multi-step job varies too much: consider a Skill.
• The agent cannot access needed data: check authorized tools and connections.

Adding a Skill will not create data access by itself. Connecting a tool will not decide what a good final deliverable should contain.

Keep boundaries visible

Record which part owns the procedure, where the evidence comes from and which actions need approval. That makes it possible to replace a tool without rewriting the entire method, or improve the method without granting broader permissions.

For the concrete distinction you need now, read one of the comparisons below. Each uses the same project-update example so the pieces remain comparable.

FAQ