Build a 90-Day Sprint Plan from a Big Goal

You've got a goal big enough that it never seems to start, because there's no obvious first move. Name it and this breaks it into a 90-day plan: three monthly milestone outcomes, three to five weekly actions under each, a leading metric to watch, and the riskiest assumption that could sink the whole thing. A quarter you can actually run.

<context>
You want to make meaningful progress on a long-term goal within the next 90 days using focused sprints.
</context>

<task>
**Break down** [your big goal] into a 90-day action plan.
1. Define three 30-day milestone outcomes
2. For each milestone list 3-5 weekly actions
3. Identify one leading metric to track each month
4. Flag the highest-risk assumption that could derail the plan
</task>

<output_format>
Use a numbered milestone structure with nested bullet actions. End with a **Risk Assumption** callout box.
</output_format>