A team wants a saved "review this PR" workflow that a person starts on purpose. Which MCP primitive fits?
Why C is the answer
A prompt
Prompts are templates that the user selects, which matches a workflow started on purpose.
In detail
- MCP prompts are reusable templates that a user selects on purpose.
- A saved workflow that a person starts fits that control model exactly.
- Prompts suit repeatable workflows that should not start without a person choosing them.
Use case
An illustrative scenario, not a real incident.
An engineering team wants a standard "review this PR" workflow. As an MCP prompt, it appears in the client's menu, and a developer starts it when ready, with the same steps each time.
See it in different ways
flowchart LR A["Model decides"] --> B["Tool"] C["Application decides"] --> D["Resource"] E["User decides"] --> F["Prompt"]
mindmap
root((MCP primitives))
Tools
Model decides
Actions
Resources
Application decides
Read-only data
Prompts
User decides
Saved templatessequenceDiagram participant P0 as Developer participant P1 as Client participant P2 as MCP server P0->>P1: Selects review this PR P1->>P2: Gets the prompt P2-->>P1: Template with arguments P1-->>P0: Runs the workflow
Key point: A person choosing a workflow points to an MCP prompt.
Why the other options are wrong
- A. A resource that the application attaches to every conversation it starts
- A resource is data. It does not start a workflow.
- B. A subscription that notifies the client each time a PR is opened
- A subscription reports changes. It does not give a person a workflow to start.
- D. A tool that the model will decide to call whenever a PR is mentioned
- A tool is called when the model decides, not when a person chooses.