Output Skeleton
Show the shape before filling it
Instead of streaming a long answer character-by-character, render the structure first — headings, section count, expected formats — then fill the slots in. Users know within a second whether they will get a 3-bullet TL;DR or a 1,200-word essay, and can start orienting before the content arrives.
Framing
The problem
Long answers stream linearly — users wait without knowing if the answer will be three bullets or three pages.
The pattern
Render the structure first (sections, formats, lengths) and fill content into the placeholders, often in parallel.
Why chat breaks here
Chat treats output as a flat character stream; the user must wait until the end to learn the shape they were promised.
Risks
Skeletons that overpromise (more sections than the model can fill well) feel like a bait-and-switch.
Avoid when
Outputs are short or freeform enough that a structural preview would be heavier than the content itself.
Use when
Long outputs have predictable structure and users benefit from seeing the shape before content arrives.
DOPE evaluation
- Directability
- Skip ahead, expand or collapse sections, reject the structure before content fills
- Observability
- The shape of the answer is visible immediately, before any content arrives
- Predictability
- Section count, format, and length envelope are declared up front
- Explainability
- Each placeholder declares what kind of content will land there (paragraph, list, table)
In the wild
- ChatGPT Deep Research (OpenAI) — Proposes a research plan card before execution; the user reviews and modifies the outline, then the agent runs. The plan-first contract made explicit.
- Gemini Deep Research (Google) — Apr 2026 launch on Gemini 3.1 Pro made the editable research plan the hero UX — the structure of the answer is shown and shaped before any content arrives.
- Claude Artifacts (skeleton behavior) (Anthropic) — Caveat — implicit, not a named feature. For long structured documents Claude often drafts headings and sections first, then fills them. Pattern visible in behavior, not branding.
FAQ
When should I use the Output Skeleton pattern?
Long outputs have predictable structure and users benefit from seeing the shape before content arrives.
When should I avoid the Output Skeleton pattern?
Outputs are short or freeform enough that a structural preview would be heavier than the content itself.
What problem does Output Skeleton solve?
Long answers stream linearly — users wait without knowing if the answer will be three bullets or three pages.
Why is chat the wrong fit for this?
Chat treats output as a flat character stream; the user must wait until the end to learn the shape they were promised.
Related patterns
- Often paired with: Progressive Disclosure — Skeleton shows the shape; disclosure lets the reader expand only the sections that matter.
- Extends: Generative UI — A skeleton is the contract before generative UI fills it in — structure first, components later.
- Alternative to: Intent Preview — Preview the plan vs preview the output shape. Both move predictability forward in time.