Markstream Vue 3

Use this skill when the host app is plain Vue 3, typically Vite-based, and not Nuxt.

Workflow

• Confirm the repo is Vue 3 and not Nuxt.
• Install markstream-vue plus only the optional peers required by the requested features.
• Import markstream-vue/index.css after resets.

- In Tailwind or UnoCSS projects, use @import 'markstream-vue/index.css' layer(components);. - The root JS import does not inject styles; use markstream-vue/index.css or markstream-vue/index.px.css explicitly.

• Start with content and choose the renderer mode by surface.

- Use mode="chat" for AI chat or SSE output. It uses lightweight batches, <pre> code rendering by default, fade=false, and max-live-nodes=0; smooth-streaming="auto" paces visible output. - Use mode="docs" for rich document surfaces. It is the default, enables larger batches, tooltips, fade, and Monaco-backed code blocks when the peer is installed. - Use mode="minimal" when the surface is lightweight but not chat. - If a docs page does not need Monaco-backed code blocks, set :render-code-blocks-as-pre="true". - typewriter only controls the blinking cursor and defaults to false. - Set :smooth-streaming="false" to preserve raw chunk cadence; set :smooth-streaming="true" to force smooth pacing even on first-screen content (may cause hydration mismatch in SSR). - When overriding mode defaults on a high-frequency stream, pair smooth streaming with :fade="false" to avoid delta fade (280 ms) stacking with high-commit pacing. - Streaming vs recovering history: in chat UIs the same MarkdownRender starts streaming and later switches to history when final=true. - Streaming: mode="chat", smooth-streaming="auto", :fade="false", typewriter=true. - Recovering/completed chat history: keep mode="chat" on the same chat row to avoid switching code renderer or layout strategy when final=true; use :smooth-streaming="false", typewriter=false, and only set :fade="true" when the host explicitly wants a history-entry animation. - Use mode="minimal" for lightweight non-chat recovered content, and use mode="docs" only for rich document surfaces, not for finalizing an existing chat message. - Switch to nodes plus final only when the app needs custom AST control, worker preparsing, or structural updates beyond pacing. - Remember that html-policy now defaults to safe, and Mermaid strict mode is on by default through mermaid-props.

• For long AI transcripts or existing message virtualizers, choose the virtual-scroll path.

- Prefer MarkstreamVirtualTimeline when the app does not already own timeline virtualization. - If the app already uses vue-virtual-scroller DynamicScroller, use useMarkstreamVirtualAdapter() and bind adapter.markdownProps(item, index) to Markdown items. - Put adapter.measureItem(item, index, el) on the outer timeline row so row chrome is included in item height. - Use Markstream's reported logical height (metrics.totalHeight through the adapter/virtualizer), not the renderer element's current offsetHeight, because Markdown node virtualization may only mount the live window. - On thread switches, save adapter.captureThreadState() together with the scroller cache; restore the scroller cache before restoring the Markstream anchor.

• Use custom-id plus scoped setCustomComponents(...) for local overrides, or import { VueRendererMarkdown } from markstream-vue and install it when the repo already has an app-level plugin entry.
• Validate with the smallest useful dev, build, or typecheck command.

Default Decisions

• Vue 3 apps default to content; choose mode before fine-tuning lower-level render props.
• Omit mode only when the surface should use rich docs defaults.
• Smooth streaming (smooth-streaming="auto") is on by default when typewriter or max-live-nodes <= 0. It only paces the content path; nodes mode is never affected.
• For manual pacing with nodes, use useSmoothMarkdownStream directly: enqueue() chunks, finish() when done, render from visible, and wait for caughtUp before final parsing.
• Streaming vs recovering history: keep the same renderer mode for a given chat row; when final=true, disable smooth streaming/typewriter and optionally enable fade. Switch to mode="docs" only when moving content into a separate rich document surface. See docs/guide/ai-chat-streaming.md for full examples.
• Prefer local component registration unless the repo already uses a shared plugin entry.
• If a Vue 3 app already virtualizes messages, keep that outer virtualizer in charge and enable virtual-scroll only on large Markdown messages.
• For vue-virtual-scroller, keep sessionKey tied to content identity (thread:item:revision) and measurementKey tied to layout identity such as width, theme, font, and density.
• When Monaco code blocks need app-level preloading, import preloadCodeBlockRuntime from markstream-vue. Existing getUseMonaco() preloads remain valid; do not import stream-monaco directly just to warm workers.
• Keep html-policy="safe" and Mermaid strict mode unless the task is explicitly preserving trusted legacy behavior.
• If a trusted surface needs pre-hardening behavior, opt out locally with html-policy="trusted" and :mermaid-props="{ isStrict: false }", and call out the trust boundary in the final handoff.
• If the host is actually Nuxt, leave SSR-specific setup to markstream-nuxt.

Useful Doc Targets

• docs/guide/quick-start.md
• docs/guide/installation.md
• docs/guide/usage.md
• docs/guide/ai-chat-streaming.md
• docs/guide/performance.md
• docs/guide/component-overrides.md