deepseek-harness/packages/client/ui-chat

description, kind

description	kind
Browser Chat target that renders Session conversation nodes, historical images, actions, localization, and scroll state.	package-reference

@deepseek-ai/dsh-client-ui-chat

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Summary

Use this package to render a browser chat from recorded Session conversations, including historical images, localized actions, and restored scroll position. Compact display folds completed-turn process rows while keeping the final answer and independently useful context visible; packed historical Assistant runs remain collapsed. Local transcript and steering submissions appear immediately, remain in their original surface, and disappear atomically when authoritative Session records arrive, while queued submissions stay outside Chat. The package does not assemble or modify model requests.

File-mention providers receive the viewed Session ID with the closing-turn owner, so links into inherited history can address the fork itself.

Table of Contents

• Reference previews
• System prompt row
• Command and failure rows
• Turn token usage
• Completed-turn footer
• Turn Process Folding
• Scroll ownership
• Model Experience
• Known Limitations and Deferred Work
• Dev Note

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Reference previews

Chat supplies file and HTTP(S) navigation through one MarkdownDelegateProvider around its node list. Assistant Markdown file links open in the right Sidebar after the message settles, including references to unmodified files. Relative paths resolve in the viewed Session's workspace; absolute paths retain the same Session's filesystem access. #L24 and #L24-L30 navigate to the first specified line and reuse an existing file tab. Missing files show the preview's error state.

Settings → General → Open chat links in selects the destination for ordinary clicks on Chat HTTP(S) links: Built-in browser (default) opens a new right-Sidebar Browser tab, while New browser tab opens an external tab. The setting is shown only while the built-in browser is available. If the Sidebar Browser is not registered, both choices use the external browser; modified clicks retain native behavior. The ui-chat.linkOpening preference persists on loopback browsers and stays process-local when settings cannot persist writes. Sent file references and skills confirmed by the message’s logged invocation also open in the right Sidebar. File paths use the viewed Session; skill names resolve through its current input-trigger source. Both use the prose file-link dotted underline on hover or focus. Sessions, directories, and command labels remain non-navigating references.

System prompt row

Each nonempty appended system/message owns a collapsed prompt row, including a complete prompt at the start of a headerless window; the same-step header does not duplicate it. Chat also shows a collapsed System prompt row for a non-empty initial request, explicit message-series start, or system/message surface node replacement whose text differs, reading the last nonempty surviving system node in surface order at the request/header; a non-initial request whose preceding header is outside the loaded history window also shows one. A resume repeats the row even when its system text is unchanged, including after pagination supplies the preceding header and system node; same-series config-only or tool-only changes, tool steps, and retries create no repetition, and a system/message event is never rendered as a transcript message. The row appears before that request's user messages, matching the provider envelope, and expands to the exact model-visible text with its original line breaks. A request whose system node is empty or outside the loaded window creates no row until the page holding the node arrives.

Command and failure rows

Generic command rows retain the ordinary command glyph in every lifecycle state; failure remains explicit through the row state and summary. A terminal Turn failure remains a separate red-dot notice; intermediate model retries do not create that notice, and an output-token limit uses the amber warning dot.

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Turn token usage

A completed Turn shows an expandable usage row only when the loaded window includes turn/start and every started model attempt reports safe, exact usage. The row omits unavailable optional buckets. Incomplete or contradictory accounting hides the complete disclosure instead of presenting a partial total.

Settings → General → Performance & usage stores ui-chat.performanceUsage as detailed (default) or compact. Compact shows only available output speed and cache-hit percentage beneath the composer, without interactive statistic dialogs or per-Turn usage. Detailed exposes session statistics and per-Turn token usage. Neither mode shows elapsed time in the completed-turn footer. The preference changes presentation only; accounting and Session events remain intact.

On non-loopback browsers, the preference remains process-local because the settings scope cannot persist writes. Explicit selections update every consumer immediately; accepted Host settings reconcile the live value on loopback browsers.

Completed-turn footer

The completed-turn action footer starts 20px below the preceding prose or extension content.

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Turn Process Folding

Each reasoning row starts collapsed, including during streaming and in reasoning-only replies. Clicking the row opens or closes its complete Markdown; incoming answer text, Tool calls, and stream completion preserve that choice. Expanded reasoning uses compact secondary typography: headings add bold weight without changing text size, line height, or color. The collapsed summary stays on one line, follows the latest reasoning line while streaming, and shows the first line after settlement.

Settings → General exposes a persisted, localized Normal / Compact conversation-display preference in the ui-chat namespace; Compact is the default. Normal leaves process rows visible and renders no Turn-process control. In Compact mode, the System prompt remains independently visible before the opening User throughout the Turn. Context injection, reasoning, Assistant material, Tool rows, and Retry rows remain expanded while a Turn is open. At turn/end, its latest Step becomes the final-answer boundary only when it contains non-blank text, an image, or an unknown visible block—and no Tool-call block; preceding Context injection, reasoning, earlier Assistant material, Tool rows, and Retry rows then collapse by default. The control reports Turn-wide durable counts for non-subagent Tool calls, reply-bearing Assistant messages before the final answer, and subagent delegation calls; zero-valued segments are omitted, the Tool and subagent figures are mutually exclusive, and neither System prompt nor Context injection contributes a count. When all three counts are zero, the process still folds and the control reads Thought for a while. A full-width divider below the summary separates it from the answer or expanded process rows. User and steering messages, System prompt, error, max-token, and turn-tail rows stay outside, and a closed Turn with no final answer keeps all process evidence visible. A newly available process control is inserted without changing the relative order of existing rows: opening human input precedes the control and process rows from their first projection, while System prompt remains above that input. While older history remains available through Load earlier, process controls stay absent and no members are hidden; once history is complete, every eligible closed Turn uses the collapsed default immediately. Stable Chat Node Seats keep every renderer mounted, hidden members add no flow spacing, and a closed control sits 8px above its answer only when no independent input intervenes. Completion collapse does not depend on tail-follow position, so a reader above the tail may see the transcript reflow. An automatic collapse that would hide keyboard focus keeps the group open and leaves focus in place; a manual close focuses the process control before hiding its members. The session-scoped store records only manually expanded Turn-and-answer-Step generations; a different answer generation starts collapsed.

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Scroll ownership

Chat restores semantic anchors across history prepend and renderer remounts, with browser scroll anchoring disabled on its scrollport only while following the tail. Pinned scroll deliveries without reader movement, and reader input that reaches the exact floor, update follow ownership immediately, before subsequent layout changes can invalidate their floor. Other reader movement remains pending until the sampling interval or scrollend, even inside the follow threshold, so layout growth cannot erase small scroll gestures. Submitting transcript input or steering immediately restores tail following and clears an older pending reader sample. While the reader is pinned to the floor, ResizeObserver follows the new floor and selects the latest loaded Turn without reading row geometry. Once the reader moves away, flow-height changes preserve the top position and the reading-line geometry selects the active Turn. Turn-rail previews paint above sticky Markdown code-block banners, while the rail frame remains inside the transcript band above the composer.

The turn rail mounts only visible marks, overscan, and the focused mark's neighbors. Its fixed pitch and observed viewport size determine scroll offsets without reading the DOM scroll extent. Initial placement waits for the body's restored active Turn and the rail's first usable viewport size. The ref controls activate a Turn or scroll the rail independently; the transcript itself remains fully mounted.

While the pointer is outside the rail, automatic follow keeps the rail still when the active mark's center is inside the fade-free band and centers it after it leaves that band. Previews follow pointer movement or focus; marks scrolling under a stationary pointer do not select another preview.

Scroll implementation — click to expand

useChatViewport owns turn-aware DOM reads, clamped writes, and native events. useChatReading owns follow policy, sampled reader input, and semantic memory; useChatNavigation owns turn jumps and history-prepend preservation. useChatScroll coordinates their committed inputs. Explicit navigation carries its measured landing into reading policy, so it does not rediscover the known target with a hit test.

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Model Experience

None, as this package renders logged conversation state in the browser and registers nothing model-facing.

KV Cache effect

None; Chat presentation does not assemble or mutate provider requests.

Known Limitations and Deferred Work

• Developer messages are not displayed — presentation is intentionally deferred; encountering developer/message throws instead of rendering a fallback row.

• The transcript reflects the loaded Session window — older transcript nodes become available only after Session Controller loads the preceding event page. Turn navigation is wider than the window: the rail merges the loaded Turns with the host turnOutline projection, so every started Turn gets a fixed-pitch mark (10px apart; a ladder taller than the frame scrolls inside it with gradient fades), and activating an unloaded mark pages history through the Turn's turn/start seq before landing on its row. Without the projection (assemblies not mounting dsh-session-turn-outline) the rail falls back to loaded Turns only.

• Rail previews are card-sized — one prompt line (50 characters) and up to three response lines (120), on loaded and unloaded Turns alike; an unloaded Turn's response arrives from the outline only once the Turn settled, so an open Turn previews its prompt (or just the Turn number) until then.

Dev Note

Working context for maintainers — click to expand

None.

Runtime invariant: No companion is published. Conversation and Slot registration enforce Chat target consistency.