Slide Format

A slides artifact is a deck: an index and one file per slide, in Claude’s slide format without its project/ prefix, so a deck moves between the two and an agent that writes one writes the other. The engine holds every version of a deck to this format when it is published (internal/artifacts/slideformat) and refuses one outside it, naming the file, the line and the rule broken; the dashboard draws, presents and prints the deck from the canonical tree the same parser produces, and never parses a slide’s markup itself.

Everything below is a closed set. What is not listed is refused, never silently dropped: a deck that publishes is a deck that draws.

• The files
• The index
• A slide
• Elements
• Styles
• Inline drawings
• Images and typefaces
• Bounds
• What is refused, and what to write instead
• Themes and layouts
• How a deck is drawn

The files

Path	What it is
deck.json	The index, and the version’s entry. A deck’s kind is told by this path: crewlet artifacts publish infers slides from a directory holding it
slides/<id>.html	One slide. The id is 1 to 64 letters, digits, _ and -, and is the slide’s name in the index, the file and its section
Any other path	Images and font files the slides and the index name, by their path from the deck’s root (images/team.png, fonts/inter.woff2)

A deck holds HTML only as its slides: every slides/<id>.html is in the index’s order, every id in order has its file, and no other .html file is accepted.

The index

{
  "title": "Quarterly plan",
  "order": ["cover", "plan", "numbers"],
  "cover": "cover",
  "sections": {
    "s1": { "description": "Where we are", "start": "cover" },
    "s2": { "description": "What we will do", "start": "plan" }
  },
  "faces": {
    "source-serif-4": { "family": "Source Serif 4", "src": "fonts/source-serif-4.woff2" }
  }
}

Key	Rule
title	Required, at most 120 bytes
order	Required: the slide ids in deck order, each once, 1 to 500
cover	Optional: the slide the gallery draws as the card’s cover, else the first
sections	Optional: the outline, any key to a run’s one sentence (at most 300 bytes) and the slide it starts at. No two start at one slide
theme	Optional: the look the deck began in, one of nightshade, ink, paper, signal, studio, grove. Crewlet’s own key, written by the starter; the slides hold their own styles, so a deck naming none draws the same. The deck editor adds a slide from that theme’s layouts, and duplicates a slide in a deck naming none. See Themes and layouts
faces	Optional, at most 4: a typeface keyed by its family lowercased with spaces as -, its family and the font file of the version it loads from (src). See Images and typefaces
v, createdOnFiles, lists	Claude’s own bookkeeping: accepted and kept as written, never read. lists may only be css
designSystems	Must be empty or absent: a Crewlet deck installs no design system

Any other key is refused, so a misspelt key is an error rather than a setting that does nothing.

A slide

A slide file is exactly one <section>, with nothing before or after it but whitespace and comments: no doctype, <html>, <head> or <body>. Every element is closed explicitly (<br>, <img> and <hr> take no closing tag, and inside a drawing an empty element may close itself, <rect/>).

<section id="plan" data-transition="fade" style="background:#fbfbf8;color:#1a1a1a;font-family:Georgia, serif;padding:128px;display:flex;flex-direction:column;gap:48px">
<h2 style="font-size:72px;font-weight:400;line-height:1.1">The plan</h2>
<div style="display:flex;gap:32px">
<p style="flex:1;font-size:32px">Every request lands in one place.</p>
<img src="images/team.png" alt="The support team" style="width:480px;height:360px;object-fit:cover;border-radius:16px">
</div>
<p style="position:absolute;left:128px;bottom:64px;width:800px;font-size:24px;color:#6a7179">Source: support desk</p>
<aside>Take the questions first.</aside>
</section>

• The stage is 1920 by 1080 CSS pixels, 16:9, laid out at that size and scaled as a whole wherever it is drawn, so a thumbnail, the editor and a projector show the same line breaks.
• The section carries id (the slide’s id, its file’s name), style (which must set a background, so the slide reads the same in every theme), and optionally hidden (Present skips it, Print leaves it out) and data-transition (fade or push: how the slide leaves the stage in Present).
• Layout. A section or <div> that names no display lays its children out as a column; display:flex is a row, display:grid a grid. Children flow; position:absolute with left, top, right, bottom, width and height pins one to the slide (or to a position:relative <div>). Later children paint over earlier ones: there is no z-index.
• Defaults. h1, h2, h3 are 96, 64 and 44px at weight 600; text elsewhere inherits from its container, 32px by default. Set sizes yourself: nothing under 24px reads from the back of a room.
• Speaker notes are plain text in one <aside>, the section’s last child, at most 4,000 characters. Everyone who can open the deck can read them.

Elements

Element	Holds	Attributes
section	blocks, then one aside	id, style, hidden, data-transition
div	blocks (at most 15 nested)	style, data-text (a text box; its value is a list indent in px, 0 to 200)
h1 h2 h3 p	text and inline marks	style
ul ol	li only (one level)	style
li	text and inline marks	style
b i u span	text and inline marks	span: style
a	text and b, i, u, span, br	href, an https:// address
br	nothing	none
img	nothing	src and alt (both required; alt="" for decoration), style
table	tr only	style
tr	th and td	style (background only)
th td	text and inline marks	style
hr	nothing	style
svg	a drawing	aria-label (required: what it shows), drawing attributes, style
x-shape	nothing	kind: rect, rounded, ellipse, diamond, arrow-right, arrow-left, arrow-up, arrow-down, line; style
x-icon	nothing	name, one of Activity, Book, Chart, Chat, Check, CheckCircle, Clock, Code, Database, Globe, Home, Key, Lightning, Link, Lock, PaperPlane, Search, Settings, Star, Tool, Trust, Users, Warning, Wrench; style
aside	plain text	none

A block is h1 to h3, p, ul, ol, div, img, table, hr, svg, x-shape and x-icon. Text sits in a text element, never directly in a section or div.

An x-icon draws its glyph at half its box, centred, as Claude’s format does; the rest of the box is padding. A width:64px; height:64px icon draws a 32px glyph, so size the box at twice the glyph you want: at least 32px, and 48px beside 24px body text.

Styles

Every style is inline, in style, from the table below, and only on the elements its row names. A value is read by its property’s grammar and stored in one canonical form: a bare number is pixels (width:480 is 480px), a point size becomes pixels (36pt is 48px), keywords are lowercased and a family name is quoted.

Grammar	Means
LEN	Npx or a bare number of pixels (pt converts); never em, rem, vw, vh or %
PCT	N%
COLOR	#rgb, #rgba, #rrggbb, #rrggbbaa, rgb(), rgba(), hsl(), hsla(), a CSS named colour, or transparent; never currentcolor or var()
ANGLE	Ndeg, Nturn or Nrad
FAMILY	up to eight family names, quoted or not, each a letter then letters, digits, spaces, _ and -, at most 40; or serif, sans-serif, monospace, cursive, system-ui

Property	Value	On
position	absolute, relative	placed elements
left, top	LEN, PCT, auto, calc(PCT ± LEN)	pinned elements
right, bottom	LEN, PCT, auto	pinned elements
width	LEN, PCT, auto	placed elements, th, td
height	LEN, PCT, auto	placed elements
min-width	LEN, min-content, max-content	placed elements
min-height, max-width, max-height	LEN	placed elements
display	flex, grid, none	section, div
flex-direction	row, column, row-reverse, column-reverse	section, div
flex-wrap	wrap, nowrap	div
gap	LEN, 0 to 512	section, div
align-items	start, center, end, stretch, baseline and the flex-/self- forms	section, div
justify-content	start, center, end, flex-start, flex-end, space-between, space-around, space-evenly	section, div
justify-items	start, center, end, stretch	section, div
align-self	as align-items, or auto	placed elements
justify-self	auto, start, center, end, stretch	placed elements
flex	none, auto, or grow [shrink] [basis]	placed elements
flex-grow, flex-shrink	N	placed elements
flex-basis	LEN, auto	placed elements
grid-template-columns, grid-template-rows	tracks of LEN, Nfr, auto and repeat(N, …), at most 24	section, div
grid-column, grid-row	span N, 1 to 24	placed elements
aspect-ratio	N or N / N	placed elements
padding	one to four LEN, 0 to 256	section, div, text elements, table, th, td
overflow	hidden, visible	div
font-family	FAMILY	section, div, text elements, table, th, td
font-size	LEN, 8 to 400	as font-family
font-weight	normal, bold, 100 to 900 in hundreds	as font-family, and span
font-style	normal, italic	as font-family, and span
font	[italic] [weight] size[/line-height] family	as font-family
line-height	a multiplier 0.5 to 4, PCT, or LEN	as font-family
letter-spacing	normal, LEN −24 to 32, or Nem	as font-family
text-align	left, center, right, justify	as font-family
text-transform	none, uppercase, lowercase, capitalize	as font-family
white-space	normal, nowrap	as font-family
text-decoration	none, underline or line-through, an optional style and COLOR (underline only on a span)	as font-family, and span
font-variant-numeric	normal, tabular-nums	as font-family
-webkit-text-stroke	LEN 0 to 8 and COLOR	as font-family
color	COLOR	as font-family, and span, x-icon, hr
background	COLOR, or one linear-gradient(), repeating-linear-gradient() or radial-gradient() of 2 to 8 stops with an optional COLOR under it (a tr, x-shape or hr takes a COLOR)	painted elements
background-color	COLOR	painted elements
background-clip, -webkit-background-clip	text	text elements
-webkit-text-fill-color	transparent, or currentcolor on a span	text elements, span
border, border-top, border-right, border-bottom, border-left	[LEN 0 to 16] solid|dashed|dotted|double|none [COLOR] (the style word is required), or none	painted elements
border-radius	one to four LEN or PCT	div, img, table, x-shape, text elements
box-shadow	up to eight [inset] x y [blur [spread]] COLOR	div, img, table, x-icon, x-shape, text elements
text-shadow	up to eight x y [blur] COLOR	text elements, table
opacity	0 to 1	placed elements, section
transform	translate(), translateX(), translateY(), rotate(), scale() (0.5 to 2), skew(), skewX(), skewY() (±60deg), each once, in that order (rotate() alone on a shape)	placed elements
filter, backdrop-filter	blur() (to 20px), brightness(), contrast(), saturate(), grayscale(), sepia(), invert(), hue-rotate()	div, img, x-shape, text elements
mix-blend-mode	normal, multiply, screen, overlay, darken, lighten	div, img, x-shape, text elements
object-fit	cover, contain	img
margin, box-sizing, grid-template	0, border-box, none only, accepted and left out

A placed element is any block a container holds; a text element is h1 to h3, p, ul, ol and li; a painted element is a div, img, table, x-icon, x-shape, hr, a text element or a cell.

No value may carry url(, image-set(, var(, env(, attr(, expression, @, a backslash, a comment, !important, <, >, { or }, whatever its property.

Inline drawings

A chart or a diagram is one <svg> with an aria-label, at most 52 KB of source: g, defs, path, rect, circle, ellipse, line, polyline, polygon, text, tspan, title, desc, use, symbol, marker, pattern, clipPath, mask, linearGradient, radialGradient, stop, filter and the feGaussianBlur, feOffset, feBlend, feColorMatrix, feFlood, feComposite, feMerge, feMergeNode and feDropShadow primitives, with their geometry and presentation attributes (fill, stroke, stroke-width, opacity, transform, viewBox and the rest the engine’s table lists).

A drawing reaches nothing outside itself: no <script>, no event attribute, no <foreignObject>, no <style> element or style attribute (use presentation attributes), and every reference (href, url(#…)) is to an id the same drawing declares. Ids are a letter then letters, digits, _, . and -. The dashboard gives each drawn copy of a drawing its own id prefix, so a slide drawn twice (its thumbnail and the stage) never resolves the other copy’s gradients.

Images and typefaces

An image is an <img> whose src is a PNG, JPEG, GIF, WebP or SVG file of the same version, by its path from the deck’s root. Never a URL, a data: address, a path starting with / or ./, or one holding ... The dashboard reads the file with the viewer’s own sign-in and shows it through an object URL of its own, so a deck makes no request a slide names.

A typeface is a faces entry whose src is a woff2, woff, ttf or otf file of the version. The dashboard loads it from the file’s bytes; a slide names it in font-family like any family, and a family that is not declared falls back to the next one the slide names, as in any stylesheet. A Google Fonts href, which Claude’s format accepts, is refused here with how to fix it: download the font file and include it in the version, so the deck draws the same wherever it is opened.

Bounds

Bound	Value
Slides in a deck	500
Elements on a slide (a drawing counted once)	200
Nested <div>s	15
Pinned children of one <div>	24
Characters of text on a slide, notes aside	20,000
Inline marks (b, i, u, a, span) on a slide	100
Rows of a table, cells of a row, cells on a slide	100, 24, 4,000
Characters of speaker notes	4,000
One inline drawing’s source	52 KB
Typefaces	4

A version’s own bounds apply too: 511 files, and each file’s size by its type.

What is refused, and what to write instead

Refused	Write instead
class, <style>, <link>, margin, z-index, em, var(), url()	Inline styles from the table; paint order is source order
<script>, an on… attribute, <iframe>, <object>, <canvas>, form controls	Nothing runs on a slide; draw in an inline <svg>
x-embed (a live page on a slide)	A picture of it as an <img>
x-connector	A line in an inline <svg>
data-build-in, data-build-out (builds)	Show the element from the start, or split the slide
data-transition="magic", an id on any element but the section	fade or push
data-section on a slide	sections in deck.json
data-crop	Crop the image file itself; object-fit covers or contains it in its box
<thead>, <tbody>, <h4>, <em>, <strong>, <pre>, <code>, <blockquote>	<tr> directly, <h3>, <i>, <b>, a styled <p>
A Google Fonts href in faces, a design system	A font file of the version in src; the company’s look comes from its own decks

A refusal lists every finding at once (up to 50), each as file:line: rule: message, under the code slide_format.

Themes and layouts

A deck begun in the dashboard is composed by the engine from a plan: the theme it is drawn in and the slides it opens with, each a layout and its title. The engine writes ordinary slides, held to this format like any version, and names the theme in the index so a slide added later is drawn from the same theme’s layouts. GET /artifacts/starters/slides answers every theme and layout (see API Endpoints).

Theme	Look
nightshade	Periwinkle on blue-black, set in Inter
ink	Navy and paper, set in Georgia (the default)
paper	White, quiet and exact, set in Helvetica Neue
signal	Yellow on black, for a big room
studio	Warm cream and terracotta, Palatino over Avenir Next
grove	Deep green and mint, set in the system face

Layout	Holds
cover	The deck’s title and who it is for; its title is the deck’s
agenda	A numbered list of the parts to come
section	Opens a part of the deck; it starts a section of the outline under its title
points	A title and a short list
columns	Two cards side by side
number	One figure, large, and what it measures
quote	A quote, large, and who said it
closing	The one decision or ask to end on

A slide’s id is its layout’s, numbered from two when a layout is used again (points, points-2).

Changes to the format

• theme in the index. Added as an optional key, so every deck written before it is still in the format. A deck that names a theme outside the list above is refused, naming the themes there are.

How a deck is drawn

• Read. GET /artifacts/{id}/versions/{n}/deck answers the canonical tree (see API Endpoints), and GET …/outline a deck’s titles and cover slide for the gallery. An agent reads the outline with get_artifact and view: "outline", then only the slide files it changes.
• Edit. A person with editor edits text in place, speaker notes, the order and the deck’s title, and deletes slides; Save publishes a version against the one they opened. The editor writes each changed slide back in this format’s canonical form, every value as the engine stores it, so a slide a person saved reads back to the same tree. A save refused because somebody published since is merged onto their version slide by slide, and what both changed differently is the person’s to resolve.
• Present. Present draws the slide as large as fits, full screen on the reader’s press, with the keys a clicker sends (Right, Down, Page Down, Space and Enter forward; Left, Up, Page Up and Backspace back; Home and End; Escape out), each slide announced by its number and title. Full screen is a projector’s: the slide on black, its controls floating over its foot and put away with the cursor while the pointer rests (a clicker’s keys do not bring them back). The Presenter window, the dashboard’s own, shows the slide, the next one, the notes and a timer, and moves the room’s screen. Anybody in the room can Follow the presenter, a phone included, and is moved to the slide they are on.
• Print. Print draws every shown slide on its own 16:9 page, so the browser’s Save as PDF is the deck as a PDF.
• Compare. History compares two versions By slide: each slide’s two versions side by side under their versions’ names, paired by id, with changed, added, removed and moved slides said in words, and unchanged ones folded away.
• Start. New › Deck, or POST /artifacts with "kind": "slides" and "starter": true, begins a deck from the engine’s starter slides.