ONE-FEATURE BRIEF — VibeGym
User: [one person or role]
Problem: [what they cannot do today]
One action: [the smallest useful thing they should finish]
Input: [what they provide]
Result: [what they can see or use]
Data: [where it is stored; use sample data first]
Not now: [accounts, payments, integrations you can postpone]

Acceptance checks:
1. Given [starting state], when [action], then [visible result].
2. With empty or invalid input, [expected response].
3. After refresh, [what should persist or reset].

Ask the agent: Explain your plan and which files you need to change. Build only this feature. State assumptions, then show how to check the result.

Source: https://vibegym.space/resources#brief