A platform team that is told "we use AI" learns almost nothing about what it must build. A browser chat service and an agent that changes claims records overnight may call the same model, yet one needs an egress rule and a sign-on policy, the other the whole reference architecture plus an identity, a budget and a stop path. This chapter organises that work by the six usage modes of large language models and sets out what each mode requires of five platform capabilities. The full taxonomy is in AI Governance, Chapter 2 (73, Nordqvist, 2026), with identical names and numbering.
The drift paths along which a use case changes mode are these.
Each mode is an architectural pattern, not a product category. The AWS scoping matrix grades generative AI by the share of the stack the organisation owns (196, AWS, n.d.); for platform and security work, however, two further axes matter more: how far the model reaches into the organisation's data and systems, and how far its output travels before a person checks it.
Primary topics explored
- The six modes in brief
- The usage modes compared
- What the platform must provide, capability by capability
- Mode changes are platform events
- Where the book builds each mode's platform
- Summary
About AI Platform and Security
AI Platform and Security is Book 3 of The Transformed Architecture. It shows how large European enterprises and public authorities build, secure and operate the platform on which artificial intelligence runs: data, models and DevSecMLOps, retrieval and agents, infrastructure and sovereignty, AI security engineering, evaluation, observability and cost.
The companion volume AI Governance covers risk management, governance, assurance, organisation and leadership; Architecture as Code supplies the underlying discipline.
Platform engineers, security architects, MLOps teams, AI architects and technical decision-makers.
Gunnar Nordqvist
Conceived, directed and published the books of The Transformed Architecture.
Continue with the full chapter
Chapter 2: Usage Modes and the Platform: What Each Mode Demands in AI Platform and Security gives the detailed explanations, practical examples and implementation patterns behind this summary.
This whitepaper belongs to “Foundations” and is one of 29 drawn from the manuscript.