shinychat

• Web search and web fetch responses from ellmer now show their activity and citations directly in the chat. Readers can open a citation beside its claim or use the message-wide Sources pill. ContentCitation@grounded_span links each citation to the answer text it supports. (#280)
• Citations are powered by a new <shiny-aside> markup convention that any assistant message can use to attach source details to specific claims — useful for custom RAG workflows. See the Asides section in ?chat_append. (#278)
• Tool call displays have been reworked to be more concise and to intelligently group multiple calls together. By default, calls render as a condensed activity row; expand a group row to see each call, then drill into a call for its full request/result card. (#283)
• Added tool_result_display(), a constructor for the display object passed as extra = list(display = ...) on an ellmer::ContentToolResult (a bare named list with the same fields still works). New label and value_preview fields (e.g. a filename, and "1,204 rows") are shown in the activity row.
• A tool's definition title (from its annotations) and its result title (from tool_result_display()) are now shown as-is, without client-side tense conjugation — the old "Running {title}" / "{title} failed" templates are gone. The definition title shows while the call is running; for a single-call row, the result title (if provided) replaces it when the result arrives, and failures are shown via a separate status cue. If a title now reads oddly while running, write it in the present tense (e.g. "Running R code").
• Control grouping with the tool_grouping parameter of chat_ui(): "tool" (default) groups calls to the same tool within a tool-calling loop, "all" groups every call in the loop together, and "none" shows one activity row per call (thinking or prose starts a new loop). Individual tools can override the chat-level setting with a grouping tool annotation, e.g. tool(..., annotations = tool_annotations(grouping = "all")).
• Set open_style = "framed" in tool_result_display() to draw a border around an open tool result's header and contents — a better fit for results with a footer or fullscreen toggle. (#331)
• Fully custom tool-result UI returned from a contents_shinychat() method is now paired with its tool request: while the tool runs it appears in the activity row, and once the result arrives the custom UI renders as standalone output. Custom results are also preserved when preloading or restoring conversations.
• Added submit_key parameter to chat_ui(): "enter" (default, Enter submits) or "enter+modifier" (Ctrl/Cmd+Enter submits, plain Enter inserts a line break). The input remains editable while a response is streaming — only submission is blocked, not typing. (#251)
• The send button is easier to customize: a new icon_send parameter on chat_ui() swaps the submit icon, and a data-state attribute exposes the button's current state for styling. (#350)
• Styling is more customizable via CSS custom properties: the set of public --shiny-chat-* variables has grown to cover the send button, history drawer, page layout, thinking display, and more, and all of them can now be overridden from :root (previously, element-level defaults always won). (#350, #355)
• Single tildes no longer trigger strikethrough in markdown. Text like (~$1.50) and ~/Documents now renders as literal text; only ~~text~~ produces strikethrough. (#349, #353)

Breaking changes

• chat_app() now configures its full-window page through page_chat(). Arguments in ... are passed to page_chat() instead of shiny::shinyApp(): use app_options instead of options, bookmark_store instead of enableBookmarking, and compose page_chat() with chat_server() when you need onStart or uiPattern. chat_app() now owns the page layout, so its title, icon, and id configure the page-chat shell. Existing layouts that embed chat should use chat_ui() and chat_server() directly. (#329)
• The messages parameter is deprecated in favor of the conversation-history feature: chat_ui(messages = ...) now warns, and chat_app(messages = ...) errors when history is enabled (the default). Use greeting for a startup message, chat_append() to replay messages, or history = FALSE if you manage state yourself. (#381)
• CSS classes and custom properties used by the external-link dialog, thinking display, and tool-result images/PDFs now use the .shiny-chat-* prefix instead of .shinychat-*. Update any custom CSS that targets these identifiers. (#285, #286)

Changes

• chat_ui() and page_chat() no longer show an assistant icon by default. Pass icon_assistant = TRUE to restore the built-in robot icon, or supply your own icon as before. (#345)
• chat_ui() now uses a wider default content width on large displays while preserving its existing width on smaller windows. (#364)
• The dismissible parameter of chat_greeting() has been renamed to persistent with an inverted value. dismissible = FALSE (greeting stays visible) is now persistent = TRUE. The old dismissible argument still works but warns. (#260)

Bug fixes

• Fixed a security issue where model-authored Markdown could create or escape into shinychat's raw-HTML islands (<shiny-chat-raw-html>), potentially injecting arbitrary HTML into the page. As part of this, output_markdown_stream()/markdown_stream() now track which parts of a mixed value are trusted server-rendered HTML versus untrusted text. (#287, #360)
• A response that fails before it streams anything (e.g. an exhausted quota, an over-long context, or a dropped connection) is now reported in the chat instead of leaving a loading indicator that never resolves and a locked composer. The chat_server() return also gained last_error, a reactive holding the condition from the most recent failed response, since both a finished and a failed response report "idle" in status. (#304, #314)
• Fixed output_markdown_stream() permanently stopping following new content after the user scrolled back to the bottom. (#282)
• Fixed expanding or collapsing a tool result yanking the chat's scroll position away from what you were reading. (#348)
• chat_app() no longer renders a close button or registers a stopApp() observer when deployed to a server. Both are now gated on rlang::is_interactive(), preventing session crashes in multi-user deployments. (#265)
• Fixed control-only inputs (the close button, cancel button, and greeting-requested signal) leaking into bookmarked state. (#258, #259)
• Fixed set_client() failing when the conversation contains an htmlwidget or tagList(). (#362, #369)
• Fixed suggestion cards and the greeting overflowing the chat container in narrow spaces such as sidebars. (#255)
• Fixed the copy button on code blocks not working in some embedded contexts. (@thisisnic, #247)