[jeffdaley]

Ticket

https://linear.app/livekit/issue/DE-211/agents-ui-announce-new-messages-to-screen-readers

Builds on #1500, which adds the composer and the transcript's labels. This PR targets that branch, so the diff shows only the announcements.

Context / reason for change

Screen reader users don't hear when the agent replies in the chat transcript. They have to go looking for new messages, which makes a text conversation with an agent hard to follow.

Summary of changes

• New messages from the agent and other participants are announced, through a new live region in the transcript.
• Announcements wait until a message stops changing for a second, so streaming replies aren't read word by word. A reply that continues after a pause announces only the new text. Transcripts are tracked by segment, since each update arrives as a new stream with a new ID.
• Each message waits for its own pause, so a long reply doesn't hold back others. A rewritten message is announced again in full.
• History and your own messages stay quiet. That covers messages on screen at mount, messages that arrive together, and messages loaded above the conversation. History is detected by order and batch rather than timestamps, since remote clocks can be off.
• Unfinished links and code spans wait up to 3 seconds to finish, so they aren't read in pieces.
• Markdown is read as plain text. Links, emphasis, and code keep their words and lose the punctuation; lone symbols like 5 * 3 stay.
• announceMessages chooses what's announced: 'all' (default), 'typed', or 'none'. AgentSessionView_01 uses 'typed', since the agent's voice already says its transcripts aloud.
• labels.messageAnnouncement gets the text and its message. The default says "Agent" for agents and the participant's name for anyone else.

Screenshots / demos

No visual change.

How to verify

Run Storybook (pnpm --filter @livekit/component-docs-storybook dev) with VoiceOver on (Cmd+F5), and open Agents UI / AgentChatTranscript → InjectMessages:

1. Press the add button. The first message is from the agent, and VoiceOver reads "Agent: This is a message from the agent." about a second later.
2. Press it again. That message is yours, and nothing is read.

Submitter checklist

• I ran the change locally and inspected the affected UI/flow myself, if applicable.
• I added or updated tests covering this change (unit, play function, or E2E), or explained why none are needed.
• I attached screenshots or a demo for user-facing changes (ideally before + after), if applicable.
• I self-reviewed the diff and removed debug code, dead code, and stray comments.

🤖 Generated with Claude Code

[changeset-bot]

🦋 Changeset detected

Latest commit: 6bd612c

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 2 packages

Name	Type
@livekit/agents-ui	Minor
@livekit/component-docs-storybook	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated
components-js-storybook-5kld	Ready	Preview	Nov 9, 2026 3:25pm UTC

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}