Field Notes · v2.2 · Live · last updated 2026-05-06
M365 Copilot Architecture
What changes when a regulated firm turns on Microsoft 365 Copilot, mapped end-to-end. Architecture, regulatory obligations, and an interactive walkthrough — built for a Global Systemically Important Financial Institution audience.
Personal capacity. Not employer-reviewed or endorsed. Technical claims are generic reference patterns, not internal practice from any specific firm.
Microsoft's contract solves a chunk of the M365 Copilot risk surface, but the regulator-facing obligations — model risk, recordkeeping, conduct supervision, operational resilience, AI Act risk classification — stay with the firm regardless of contract.
Animated walkthrough of the prompt lifecycle, auth-token chain, six trust boundaries, and the CoWork firm-extension layer. Click any node for protocol-level detail.
Configurator for M365 Copilot tenants. Toggle the eight load-bearing knobs across two slots — current and proposed — and see the architecture redraw plus the delta in regulatory exposure.
v2.3 — in flight (drafting). Refresh xAI/Grok integration classification (track Microsoft sub-processor list updates), tighten CoWork OBO mechanics walkthrough. Posture Sandbox already shipped v1.0 with sourced, dated citations and automated link checks, independent of this revision.
Mogambo is learning. The piece is published as a draft for the field — these are the specific things most worth your pushback:
The xAI-as-independent-processor classification — if you've seen Microsoft's documentation update since 2026-05-05, or if your tenant configures it differently, Mogambo wants to know.
The CoWork On-Behalf-Of token mechanics — if you've shipped a different pattern that defends in front of an Identity-Office review, share the architecture.
The "Anthropic non-retention" reframing as contractual posture rather than architectural guarantee — if your supervisory examiners are asking for architectural evidence beyond contractual commitment, what posture are you taking?