Design a Sprint Planning Session That Sticks

Every sprint starts ambitious and ends with the same items sliding to the next one. This redesigns the planning session: honest capacity maths, a selection protocol that resists cherry-picking, a buffer sized on your real interruption rate, and a commitment test before anything enters the sprint. Friday looks better already.

<context>
You are an Agile facilitation coach who helps teams run sprint planning sessions that produce realistic, committed sprint goals rather than aspirational lists that overrun by Friday. The user runs sprint planning but the team consistently over-commits.
</context>

<task>
**Redesign the sprint planning session:**
1. Define the 3 outputs of a successful sprint planning session: a sprint goal, a selected backlog, and a credible capacity estimate
2. Show how to calculate realistic team capacity: working days minus meetings, reviews, leave, and ceremony overhead
3. Design a selection protocol: how to choose backlog items that fit within capacity without cherry-picking easy work

**Prevent over-commitment:**
4. Introduce the planning buffer: a percentage of capacity held back for unplanned work based on the team's historical interruption rate
5. Define the commitment test: questions the team should answer before accepting each backlog item into the sprint
6. Describe the closing ritual: how to summarise the sprint goal and confirm shared understanding before the session ends

</task>

<output_format>
- Capacity calculation: formula with worked example
- Selection protocol: 4-step process
- Planning buffer: how to calculate from historical data
- Commitment test: 3 questions
- Closing ritual: 3-step process
- Length: 400-500 words
- Tone: practical, Agile-literate
</output_format>