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  - **Ask a Question** uses the D365 knowledge base (requires published articles); can be extended via Copilot Studio knowledge sources (Preview: see `feature-copilot-knowledge-sources.md`)
  - **Custom instructions** (up to 5,000 chars) configure Copilot tone, style, formatting: apply to Ask a Question with D365 KB only; not applied when using Copilot Studio knowledge sources
  - **Trusted webpages** (up to 5 domains, 2 levels deep): used for email/draft responses only: **not** for Ask a Question; requires Bing enabled in Power Platform admin center
+ - **Trusted webpages are on borrowed time (September 2026).** Microsoft added a CAUTION to the admin page saying email generation from trusted webpages might not work as expected, because the underlying Bing Search API is being retired. See [Bing Search API retirement](https://learn.microsoft.com/en-us/lifecycle/announcements/bing-search-api-retirement).
  - **Proactive insights**: Copilot surfaces knowledge answers during active conversations without rep manually requesting them
  - Knowledge base content refreshed **daily**: recently published articles may not appear immediately
  - **Conversation summary** is Copilot Service workspace only: not Customer Service Hub or custom apps
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  ## Gotchas
  - **Custom instructions are bypassed with Copilot Studio sources.** If the client switches to extended sources (SharePoint, uploaded files), custom instructions won't apply. Make this clear during setup.
+ - **Don't design around trusted webpages any more.** The feature is still configurable and still appears to work, and the Bing Search API behind it is retiring — so it will degrade quietly rather than throw an error. If a client's email drafting depends on an external domain today, that is now a risk to raise, not a capability to sell.
  - **KB content takes up to 24 hours to refresh.** Newly published articles won't show up immediately. Set expectations: publish new articles at least a day before Copilot testing.
  
  ## Consultant notes
  
  - Custom instructions are worth investing real time in for any client with a distinct communication style. The default Copilot tone is competent but generic: even 30 minutes of custom instruction writing (tone, prohibited phrases, formatting preferences) noticeably improves the quality of Ask a Question responses for that client's context.
  - KB refresh being daily is a prep item: publish all articles at least 24 hours before any Copilot testing starts. Discovering this during UAT when reps can't find freshly published articles is an avoidable delay.
+ - The trusted-webpages retirement is worth a proactive conversation with any client using it. Nothing will break loudly: drafts will simply stop reflecting the external content, reps will assume Copilot has got worse, and it will be logged as a quality complaint rather than a platform change. Get ahead of it and agree where that content should live instead — usually a knowledge article.
  - Proactive insights should be piloted with a small group before rolling out to all agents. In a busy contact centre it can feel intrusive: answers surfacing when the rep hasn't asked for help yet disrupts flow for experienced agents. Newer agents tend to value it more.
  
  ---
  
- *Source last updated: check Microsoft Learn | Check this after custom instructions extend to Copilot Studio sources or proactive insights GA*
+ *Revisit when the Bing Search API retirement lands and trusted webpages either get a replacement or disappear, or when custom instructions extend to Copilot Studio sources*