Stack Ownership Boundary
For a technology leader the question is not which logo to pick but where to draw the ownership boundary. Two axes give the answer: how fast a component changes and how unique it is to your environment.
These are two independent axes rather than a single spectrum. Rent fast-changing, low-uniqueness capabilities such as frontier models. Adapt fast-changing seams that must fit your environment: harness integration, context packaging, and tool descriptions. Own the more durable, unique contracts that define the right to act: identity, policy, domain actions, episodes, and acceptance criteria.
The build gate asks five questions: is the action environment unique, are sovereignty or strict latency constraints non-delegable, does scale repay ongoing adaptation, are evals mature, and is the agent loop part of the customer-facing product? Zero or one yes means rent, two or three adapt, and four or five build; the fifth answer strengthens the business case.
Score each stack component on two axes: how fast it changes and how unique it is to your environment.
Sort the components into the three zones and name an owner for each zone.
Score the five build-gate conditions: 0–1 yes means rent, 2–3 adapt, and 4–5 build; the fifth answer carries special weight.