Microsoft Copilot Studio Platform - Build 2026.5.4

This article describes the fixes and improvements to existing functionality that are included in this build.

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Version 2026.5.4 updates

Multilingual voice agents using non-real-time TTS can apply voice, speaking rate, and pitch per language within a session.
Multi-agent analytics adds an inventory endpoint that powers an overview page with per-agent key metrics and time-series trends.
Custom metrics analytics adds trend and over-time views in the summary.
Agents can extract and return multiple values for entities in responses by default.

Breaking changes: GPT-5 Auto is no longer available for enhanced task completion agents; agents overview analytics now exposes a single "Total sessions" metric (with trend) and removes prior session-type counts and daily time-series breakdowns.
SharePoint search rate limits now return HTTP 429 (Too Many Requests) instead of HTTP 500, enabling correct retry handling.
Maker Evaluation enhancements: per-metric explanations and raw groundedness score; more reliable knowledge grading; accurate OpenAPI response types for clients; less strict groundedness for enhanced task completion agents; US Government cloud uses GPT-4.1 for improved multi-turn reliability and structured outputs.
Streaming and citations: streaming responses are enabled only when supported by the widget or SDK; citation numbering remains correct and distinct during streaming.
Agent experience: default fallback topic when input is unclear or silent; improved publishing of skill-based and runtime triggers; teams SSO sign-in flows are more resilient; clearer 400 errors when unmanaged customizations are blocked; content moderation level is honored for inline and child agents.
Continued improvements to performance and reliability.

Safe sharing governance can enforce maker connection sharing policies when agents are shared, published, or run.
Sharing an agent to an intended Analyst is blocked if the user effectively has Environment Maker role, preventing unintended elevation.
When unmanaged customizations are blocked by administrators, operations now return 400 with the Dataverse admin message (instead of 500), improving governance transparency.
Agents are less likely to fail with access denied when using existing connections, as access can be granted and requests succeed on retry.
Improved multi-owner support keeps sharing permissions in sync so additional owners and readers receive correct access.
On-Behalf-Of authentication loops in Omnichannel Live Chat Widget are resolved to prevent infinite sign-in and ensure proper user profile initialization.