Who participates

The group composition changes significantly from Phase 1. In Problem Phase, the team needed to be protected from hierarchical influences. Here the opposite occurs: stakeholders who were explicitly excluded from discovery are needed for alignment.

Participant	Role in this phase	Why they participate now
Product team	Leads the process. Presents solutions, facilitates feedback, integrates iterations.	They understand the problem most deeply after discovery. They serve as guardians of fidelity to the Problem Statement.
Business stakeholders	Evaluate economic viability, KPI impact, strategy alignment.	The business dimension of the solution needs their perspective. An ROI the technical team considers obvious may be unviable for the business.
Technical stakeholders	Evaluate technical viability, integration constraints, architectural implications.	The architecture and data dimensions need their perspective. An elegant solution that doesn't integrate with existing systems is not a solution.
Design / UX	Evaluates user experience, adoption, friction.	If the solution is technically perfect but nobody uses it, it doesn't solve the problem.
Operations	Evaluates operability, maintenance, operational scalability.	A solution that works in pilot but collapses in production is not a solution.
Selected clients or users	Validate that the proposed solution solves their real problem.	The user who validated the Problem Statement now validates that the solution makes sense to them. Their perspective prevents silent drift from the original problem.

Insight

The breadth of the group depends on the solution's impact. An operational component affecting one team can be aligned with 5-8 people. A core transformation affecting the entire organization may require 15-20. The rule is: if someone can block the solution after it's built, they should participate in alignment before it's built.