What you have now (six layers)
Portfolio → Program → Epic → Feature → Story → Sub-task. All of it exists to decompose work for human cognitive limits. If agents execute complete features from specifications in hours, why six layers?
What a complete specification looks like — instead of five separate stories about filtering by date, write one specification: API contract (POST endpoint, p95 latency target), behavior (given X transactions, when filtering, then paginate), security requirements, performance targets, edge case tests. Time with agent: 4-6 hours. Agent implements everything — code, tests, docs — in 4 hours. No separate test stories. No separate security review.
The three-layer replacement
Investment Themes — where you place capital: Customer acquisition efficiency, Platform resilience, Revenue expansion.
Software Features — what you are building: Multi-currency payments, Fraud detection, Self-serve onboarding.
Executable Specifications — what done looks like. Written with the agent in 4-6 hours. Complete enough that the agent implements everything — code, tests, docs — in one pass.
Rapid waterfall
6-hour spec → 4-hour implementation → immediate gap revelation → trivial to fix. Waterfall's comprehensive specs plus agile's rapid feedback loops.