The dominant 2026 shadow-AI gap is not unsanctioned vendors but sanctioned vendors that have shipped agentic capabilities inside already-approved tenants without triggering a re-evaluation in the customer's SaaS approval process. The canonical examples are Microsoft 365 Copilot Studio inside approved M365 tenants, Slack AI and Slack agent platform inside approved Slack workspaces, Notion AI agents hub inside approved Notion workspaces, ServiceNow Now Assist inside approved ServiceNow tenants, Atlassian Rovo inside approved Atlassian estates, and Salesforce Agentforce inside approved Salesforce contracts. Existing 2024-era shadow-AI discovery playbooks (oriented to vendor-discovery and DLP egress detection) do not surface this class because the vendor is in-policy and no egress boundary is traversed. The structural fix is procurement-side: a re-evaluation trigger inside the SaaS approval policy that runs the original data-class and risk-assessment workflow against any new agentic capability inside an existing tenant within 30 days of activation.

Claim is scoped to the intra-vendor unapproved-capability class of shadow AI as the dominant 2026 enterprise gap. Does not assert the 2024 unsanctioned-tool problem has disappeared — it remains real, but is no longer the dominant exposure for enterprises that have run the 2024 playbooks. 60-day review cadence calibrated to vendor capability-release cycles and audit calendars. Trigger conditions: (1) any named SaaS vendor publishes a customer-facing re-evaluation API or capability-change notification feed by default — would move toward Partial because the discovery gap is closing structurally; (2) a published 2026 enterprise breach or compliance finding traceable to an intra-vendor unapproved-capability shadow-AI deployment — would either confirm or scope the structural argument; (3) updated DLP product capability covering intra-vendor agentic surfaces from Microsoft Purview, Symantec, Netskope, or Zscaler — would change the technical defensive layer materially and reduce the procurement-side urgency; (4) ISO 27001 surveillance audit findings or SOC 2 deficiency reports in 2026-2027 citing the gap as a control weakness — would empirically anchor the audit-consequence argument.