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AB-900 deep review — September 27, 2026

The complete guide was read and 53 published October 14 objectives in ten groups were mapped to guide sections. July 22 remains the accepted baseline until the announced change. The live page now contains future scope, so its expected hash difference is recorded without overwriting historical snapshots. Existing teaching already distinguishes app registrations from Enterprise applications.

Learning improvements

Four worked examples teach restricted-site permission intersections, alert-only PAYG budgets, scheduled-prompt execution after UI disablement, and separate agent/file revocation. The guide also adds:

  • Separate restriction configuration for private/shared channel sites.
  • August's Connected Experiences control change and the special scheduled-prompts environment's fixed DLP policy and recreation behavior.
  • Pending agent updates versus the version users can still run.
  • Current BYO MCP preview/client limits and gradual rollout of the License Requests page, without treating approval or an absent menu as proof of effective access.

A seventh lab asks learners to prove the changed object and remaining access or execution. All eight existing questions now have answer checkpoints, with six new scenarios: seven labs and 14 answers. Three Boolean access cases and one synthetic budget-overrun calculation were checked offline; no tenant actions were executed.

Blog decision

Microsoft Mechanics' Agent management updates in the Copilot Control System, posted by Zachary-Cavanell on May 19, 2025 and presented by Jeremy Chapman, was accepted for its administration/control map. Its public embedded article and transcript were read. The guide qualifies older navigation and message-based billing terminology against current Agent 365 and Copilot Credits guidance, with attribution, reading estimate and an original exercise. The video was not played and tenant steps were not executed.

Evidence and limits

ADLC_Docs/operations/2026-09-27-ab-900-deep-review.json preserves prior catalog records, guide hashes, all objective positions/hashes and section mappings, source observations, blog decision and validation. The objective count describes the published October version; the existing effective-date follow-up remains necessary.

Three paid catalog pages were access-blocked, and retained durations are historical observations. A reachable practice-assessment shell does not prove signed-in session access or completion. No Microsoft 365, Purview, billing, scheduled-prompt, agent or MCP lab was executed. Feature-specific rollout, licensing and preview limits remain visible. Research/repair used the same AI context; independent and human review are pending.

Publication uses the unit-test, repository, strict site-build, generated-site and diff checks. See the Microsoft review tracker for remaining certifications and dated follow-ups.