AI-native Office surfaces for the browser, backed by deterministic native automation.

Edit documents, Markdown, spreadsheets, presentations, and PDFs inside your product.
Keep persistence, identity, collaboration, authorization, and AI in your host application.

Playground · Documentation · Quick start · Editors · Automation · Architecture · Contributing

A3S Office is an open-source Office engine for product teams that need rich browser editing and agent-ready file automation without adopting an A3S backend. It ships complete editor surfaces, typed host contracts, browser file workflows, and a separate Rust automation plane.

• Embed complete editors through React, Vue 3, Web Components, or the framework-neutral Core API.
• Keep format-native behavior instead of forcing every file through one lowest-common-denominator model.
• Own the product boundary: your application controls content, storage, permissions, collaboration, and model providers.
• Automate deterministically through the native CLI, standard MCP server, or packaged Office Skill.

The images below are committed visual-regression baselines from the real Playground, not conceptual mockups.

Spreadsheet — workbook editing and formula workflows	Presentation — structured slides, objects, and presenter flows
Markdown — GFM source and synchronized preview	PDF — PDFium rendering, forms, annotations, and save

• Product-native UI — Complete Office-style surfaces with no required backend, account system, or storage model.
• Accessible responsive shell — Compact sidebars, slide navigation, AI panes, responsive chart inspectors, dialogs, menus, and popovers share bounded keyboard navigation, background isolation, topmost Escape handling, and focus restoration. Persistent desktop navigation and the temporary phone drawer keep separate open states, so live breakpoint changes never turn a desktop sidebar into an unexpected blocking modal or steal focus from the workspace. Shared color palettes expand to an eight-column touch layout on phones while preserving spatial arrow-key navigation.
• Editor-scoped zoom — Status controls and Ctrl/Cmd + mouse-wheel gestures share each surface's bounded zoom model without changing the host browser's page scale.
• Predictable state — Controlled content values, typed callbacks, explicit file actions, conflict-aware document edits, and one document typography baseline across editing, preview, and PDF rendering. Word editing and read-only preview retain the same canonical TipTap tree, while browser PDF export captures that same Worker/WASM page layout instead of rebuilding content from compatibility HTML. Caption numbering and cross-reference validity also update in that same transaction graph, including a truthful missing-target state after deletion. Paired Word bookmarks can span blocks, retain stable native identities through edits, drive live editable REF fields, and keep internal links distinct from external hyperlink relationships; deleting a target exposes truthful missing-link and missing-reference states that undo repairs. Footnote and endnote references remain paired with one editable definition, renumber live in independent reference-order sequences, receive new identities when copied, and are deleted or restored together through one undoable transaction. Body PAGE, NUMPAGES, SECTION, SECTIONPAGES, DATE, and TIME fields are atomic, copied under fresh stable identities, and resolve from the live Worker/WASM page containing each field. Automatic reflow updates numeric fields without adding history or ticking clock fields; F9 refreshes every field in one undoable action. Safe inline DOCX fields round-trip natively, while nested, incomplete, cross-paragraph, deleted, or instructionless structures stay text and produce an explicit compatibility warning.
• Framework choice — React components, Vue 3 adapters, Custom Elements, and a framework-neutral Core API over the same engine.
• Responsive computation — Lazy editor chunks, cancellable Workers, CSS-compatible font-weight matching, Rust WebAssembly layout and calculation, and PDFium rendering.
• AI without UI scraping — Typed agent ports and host-defined selection actions receive structured context and editing commands.
• Automation outside the browser — The native Rust CLI, standard MCP server, and Office Skill share bounded mutation contracts.

Node.js 20+, Bun 1.3+, and Rust 1.85+ are required.

git clone https://github.com/A3S-Lab/Office.git
cd Office
bun install --frozen-lockfile
bun run playground

Then open the local URL printed by the development server. For a zero-install tour, use the live Playground.

Install the public package with its React peers:

bun add @a3s-lab/office react react-dom

Import the stylesheet once, give the editor an explicit-height host, and store the complete value emitted by onChange:

import { useState } from 'react';
import type { DocumentContent } from '@a3s-lab/office/core';
import { DocumentEditor } from '@a3s-lab/office/react';
import '@a3s-lab/office/styles.css';

const initialContent: DocumentContent = {
  type: 'document',
  html: '<h1>Project brief</h1><p>Start editing here.</p>',
  pageSize: 'a4',
  pageColor: '#ffffff',
};

export function ProjectBrief() {
  const [content, setContent] = useState(initialContent);

  return (
    <main style={{ height: '100dvh', minHeight: 0 }}>
      <DocumentEditor
        content={content}
        onChange={setContent}
        theme="system"
      />
    </main>
  );
}

The editor owns editing, layout, import/export, and browser rendering. The host owns persistence and decides when, where, and how the emitted content is saved.

Give each mounted document a stable artifactId, then pass the matching, current artifact to downloadArtifactPdf. Export waits for the live pagination surface and crops the physical pages computed by the editor:

import { useState } from 'react';
import {
  createArtifact,
  downloadArtifactPdf,
} from '@a3s-lab/office/core';
import { DocumentEditor } from '@a3s-lab/office/react';

export function DocumentWithPdfExport() {
  const [artifact, setArtifact] = useState(() =>
    createArtifact('blank-document'),
  );

  if (artifact.content.type !== 'document') return null;

  return (
    <main style={{ display: 'flex', height: '100dvh', flexDirection: 'column' }}>
      <button
        type="button"
        onClick={() => void downloadArtifactPdf(artifact)}
      >
        Export PDF
      </button>
      <section style={{ flex: 1, minHeight: 0 }}>
        <DocumentEditor
          artifactId={artifact.id}
          content={artifact.content}
          onChange={(content) =>
            setArtifact((current) => ({
              ...current,
              content,
              revision: current.revision + 1,
              updatedAt: Date.now(),
            }))
          }
        />
      </section>
    </main>
  );
}

The live path preserves automatic page-break decorations, shaped text, table continuations, and page chrome. It currently rasterizes each physical page into the PDF; searchable text and vector output remain future fidelity work.

• @a3s-lab/office/react — Lazy React editor components and preload helpers.
• @a3s-lab/office/vue — Vue 3 adapters with v-model:content.
• @a3s-lab/office/web-component — Custom Elements for framework-agnostic UI composition.
• @a3s-lab/office/core — Typed models, templates, import, export, and browser file workflows.
• @a3s-lab/office/styles.css — Shared editor and interaction-system styles.

Copyable React, Vue, and Web Component examples live in the component documentation.

Each surface keeps a canonical model that matches its file format and user interaction model.

• Document — Pagination, sections, focused page-setup tabs, clean page margins with on-demand header/footer editing, outline navigation with contextual full-text results, keyboard-operated live physical-page raster thumbnails with viewport-bounded capture, and shared virtualized long-document windows for page buttons, heading rows, full-text results, and tracked-revision and anchored-comment review that preserve native scroll distance, sparse current/selection/draft pins, and Home/End reachability; a WPS-familiar command catalog, quick-access undo and redo, a priority-aware adaptive and persistently collapsible ribbon whose tabs can temporarily expose commands; WPS-oriented Insert groups and direct Page Layout presets for margins, orientation, paper size, and columns, with matching advanced Page Setup destinations; WPS-oriented References, Review, and View groups, direct tracked-change navigation and decisions, contextual object tabs, and viewport-calculated 100%, one-page, and page-width zoom; an actionable status bar with live word-count details, WPS Ctrl+Shift+G, keyboard-traversable view and zoom controls, and compact Web prioritization; editor-scoped WPS formatting, paragraph, style, and review shortcuts, plus a permission-free formatting clipboard and one-shot format painter shared with compatible header and footer formatting, paragraph styles and phone-sized paragraph-spacing and pagination controls with touch targets and exact invoker-focus restoration; stable compact-ribbon edge paging and viewport-bounded list galleries with touch-sized numbering actions, selection-preserving bullet and numbering commands, and explicit Escape-to-invoker focus restoration; grouped bundled, common system, monospace, imported, and host-provided font choices with live typeface previews, independent table layout algorithms, auto, percentage, or pixel preferred widths, left/center/right placement, indentation, table-level cell margins, cell-level margin overrides, and rendered column measurements for autofit tables. One Table Properties dialog presents table, row, column, and cell tabs. It combines preferred width, placement, and indent with selected-row height and pagination, current-column width, and selected-cell vertical alignment and margins. The complete draft commits in one TipTap transaction and one undo record while untouched imported measurements and partial margin inheritance retain their exact source values. Cancel and Escape discard the draft and restore the exact ribbon invoker; compact layouts keep tabs, numeric steppers, and footer actions touch-sized. A contextual Picture Properties workflow combines centimeter width and height, a per-image aspect-ratio lock, inline/square/top-and-bottom wrapping, alignment, text distance, and alternative text. It commits only changed fields in one TipTap history entry, preserves untouched imported dimensions exactly, and retains the image selection and invoker focus after apply, cancel, or Escape on desktop and phone layouts. A reusable table-border pen with all, outside, inside, and individual-edge targets, per-edge DOCX border preservation, and bounded basedOn table-style inheritance with whole-table, banded row or column, first/last row or column, and corner-cell formatting. Conditional fills, borders, bold, italic, underline, strikethrough, fonts, and text colors are materialized before direct table, cell, paragraph, and run formatting. Conditional paragraph alignment, direction, indents, spacing and line rules, pagination rules, and tab stops use the same precedence chain. Theme tint and shade values resolve for table borders and cell fills across edit, preview, and RGB-stable export. Splittable table rows that exceed a full physical page continue at paragraph boundaries with repeated heading rows on every page, viewport-safe comment drafting and focus-preserving citation drafts, tracked changes, notes, pointer- and Shift+F10-accessible host-defined selection menus, and shared edit/preview/PDF typography and page-chrome placement. Editing, read-only preview, and browser PDF export share one live pagination result. Tail edits reuse the stable physical-page prefix, including resolved first/odd/even headers, footers, page numbers, and navigation descriptors. Real DOCX fixtures provide deterministic A3S Test evidence for inherited table styling across edit and preview, a centered 62.5% table with table and cell margin overrides, all four Table Properties tabs at 390 px, exact preservation of untouched cell-margin edges, a complete 390 px Picture Properties flow, and a 120-paragraph row across three physical pages through the final table content and following paragraph. A direct-formatting A4 fixture also runs through a real WPS Writer PDF export and a page-only browser comparison. Its automatic line spacing, paragraph gaps, centered fixed table, row heights, borders, fills, and cell margins stay within the checked one-pixel layout-landmark budget while preserving the original OOXML line multiples for DOCX export. Separate 30-row common-font, 36-row CJK-font, 18-row document-grid, and 30-row multilingual-script matrices now gate text-band positions against WPS. DOCX import selects the Word ascii, hAnsi, eastAsia, or cs font slot from the run script, including complex-script bold, italic, size, and RTL overrides. The browser keeps the measured per-font automatic-line advance, while DOCX round trips retain the section docGrid type and line pitch and each run's snapToGrid override. DOCX import/export; PDF export.
• Markdown — GFM source, visual editing, synchronized and resizable split preview, source-native undo/redo with typing coalescing and selection restore, source-aware ribbon formatting and shortcuts, empty-source guidance, task lists, tables, links, images, code, a flat reading surface with a comfortable line length, and keyboard-accessible host-defined selection menus across both editing surfaces. At phone widths, Source and Preview each use the complete workspace instead of being compressed into two stacked panes. Markdown import/export.
• Spreadsheet — Multiple sheets, formulas, dependency-aware recalculation, live selection statistics, an A3S-owned worksheet bar with lifecycle and color controls, safe deletion confirmation, in-place rename validation, a grid-aligned single-row responsive workbook footer that keeps the active worksheet and its actions visible across window and phone-width changes, selection-preserving undo/redo, deterministic Arrow, Enter, Tab, Home, PageUp/PageDown, row, column, and all-cells selection shortcuts, Cmd/Ctrl formatting through root-scoped capture before vendor grid listeners, an editor-owned Cmd/Ctrl+F search bar that finds displayed values, raw values, formulas, and sparse cells without opening browser Find, with a viewport-safe phone layout, touch-sized controls, and exact grid-focus restoration, desktop workbook task panes that become focus-contained phone dialogs with an inert workbook background and exact ribbon-invoker restoration, a WPS-familiar command catalog and tab order, quick-access Undo and Redo, a priority-aware adaptive and collapsible ribbon with temporary tab expansion, an executable Home clipboard group whose Paste, Cut, and Copy commands share the permission-resilient local fallback with their WPS shortcuts, a WPS-style Format Painter with single-use and double-click locked sessions, cross-sheet range-pattern tiling, Escape cancellation, and native style-only writes, Conditional Formatting under Home and Styles, executable sorting plus WPS-style AutoFilter under Data, finite current-region discovery, Cmd/Ctrl+Shift+L toggling, an Alt+ArrowDown keyboard filter menu, a Home and Cells Rows and Columns menu for inserting above, below, left, or right and deleting selected rows or columns through the shared structure command port, a Home and Alignment Merge and Center split control with Merge Cells, Merge Across, Unmerge Cells, Unmerge and Fill, and the WPS Ctrl+M shortcut through one controlled native workbook batch, a Home and Editing Clear menu for independently removing content, formats, comments, hyperlinks, or all cell state while preserving merge geometry, with Delete and Backspace mapped to Clear Contents, a View and Window Freeze Panes menu for current-cell, top-row, first-column, and unfreeze patterns with XLSX round trips, and visible F9 workbook recalculation, Shift+F11 creation, Ctrl/Cmd+PageUp/PageDown switching in edit and read-only preview, one shared cell/worksheet context-menu surface with executable shortcut hints that becomes a touch-sized, scrollable bottom action sheet on phones, keyboard-operated cells and sheet tabs, direct type-to-edit, permission-resilient multi-cell cut/copy/paste, clear, F2 editing, and focus-safe Escape behavior, direct font-family, vertical-alignment, text-wrap, number/percent, and decimal controls, charts, validation, protection, comments, and print settings. XLSX, XLS, ODS, and CSV import; XLSX and PDF export.
• Presentation — Typed slide scene graph, multi-selection, groups, object transforms, keyboard-accessible table-size insertion, Shift+F10-accessible native slide and object context actions, guides, comments, transitions, editor-scoped formatting and clipboard shortcuts that restore the selected object, a docked desktop chart inspector that becomes a focus-contained modal surface whenever it overlays the canvas, docked desktop comment review that becomes a readable, touch-sized, focus-contained full-editor modal on phones with dirty-draft cancellation and exact invoker restoration, a dismissible phone slide navigator, a top-aligned phone canvas with a priority-aware status bar, one-step slideshow from the beginning or current slide, keyboard-complete playback, and a responsive presenter view with one navigation strip, current/next context, speaker notes, and a session timer. PPTX import/export; PDF export.
• PDF — PDFium rendering, navigation, search, form filling, annotations, annotation color, opacity, compatible stroke-width controls, history, a scrollable page-thumbnail rail with current-page synchronization and focus-synchronized Arrow/Home/End navigation, bounded rendering for long files, and a dismissible page drawer whose phone trigger stays in the page controls instead of covering PDF content, focus-safe page and search drafts, responsive search-result, navigation, and zoom controls, editor-scoped shortcuts, and a keyboard-operated overflow menu that retains secondary annotation tools and appearance settings on phones. PDF open/save.

Document and Markdown accept public TipTap Extensions. Spreadsheet, Presentation, and PDF expose stable host ports rather than their internal command contexts. Editor engines and large runtime assets load only when that surface is requested.

A3S Office is headless at the product boundary, not at the UI boundary. The package includes complete toolbars, ribbons, panes, popovers, and dialogs while leaving product infrastructure to the host.

A3S Office owns: editing models and commands; import, export, layout, and rendering; editor UI and responsive interactions; typed selection and agent ports.

Your host owns: persistence and version history; identity, permissions, and collaboration; the application shell and navigation; AI providers, prompts, policy, and request lifecycle.

Document and Markdown selection menus can be replaced with host-defined typed actions. Each action receives an immutable selection snapshot, nearby text, the complete controlled content, and conflict-aware replaceText, insertBefore, insertAfter, and copyText commands. Markdown snapshots also identify whether the source or visual surface owns the selection. Async edits track unrelated visual-editor transactions and fail with stale-selection instead of changing the wrong text. The Playground's open-ended question action enters a focused draft before dispatch, so a host never receives an unfinished “Question:” request; attached context stays available without dominating the assistant surface.

The Core API creates typed blank artifacts and performs browser-side import or export without mounting an editor:

import {
  createArtifact,
  createArtifactBlob,
  importOfficeFile,
} from '@a3s-lab/office/core';

const imported = await importOfficeFile(file);
const output = await createArtifactBlob(imported);
const blankDeck = createArtifact('blank-presentation');

Use downloadArtifact to start a browser download or createArtifactBlob when your application owns upload and persistence. Imported DOCX artifacts are source-backed: safe source-only OPC parts, content-type registrations, and relationships survive a regenerated export. Persist the original Blob alongside the artifact and call registerSourceBlob after a browser reload. If that source is unavailable, DOCX export fails explicitly instead of silently dropping complex package state. The artifact's source metadata carries a SHA-256 fingerprint, so registering a different DOCX under the same artifact ID also fails. Generated core parts remain authoritative; compatibility diagnostics identify known inline OOXML normalization and the deliberate removal of invalid signatures, VBA, ActiveX, and custom-ribbon parts. Within word/settings.xml, relationship-free ignorable attributes, elements, and structurally valid, non-conflicting mc:AlternateContent blocks survive strict or transitional UTF-8/UTF-16 sources. Generated Word settings still win, and this preservation does not yet restore behavior-changing settings. Regenerated word/styles.xml and word/numbering.xml also retain relationship-free passive extensions at the root and on uniquely matched identities. Styles match by type plus style ID; imported abstract-numbering, concrete-numbering, and level metadata follows regenerated IDs. Source-only or duplicate identities, malformed trees, relationship-bound content, and ambiguous one-to-many numbering mappings are dropped. Generated Word style and numbering semantics still win. In regenerated document, header, footer, footnote, and endnote parts, relationship-free passive extensions from non-OOXML ignorable namespaces also follow uniquely matched picture drawings, using normalized anchor and drawing-property IDs. Body, header, footer, footnote, and endnote imports retain those image identities in sanitized editable HTML. Passive extensions also follow uniquely matched, unchanged paragraphs and their paragraph properties by native w14:paraId plus w14:textId. Body and page-chrome HTML retain these identities; text edits rotate textId, formatting-only edits and moves keep it, and copies or splits receive new paragraph IDs. Source-only, duplicate, changed-text, relationship-bound, Microsoft/OOXML semantic, and ambiguous branches are dropped; generated paragraph and drawing semantics stay authoritative. Stable table hierarchies use native row w14:paraId plus w14:textId, ordered directly owned row IDs for tables, and directly owned paragraph IDs for cells. Passive extensions on w:tbl/w:tblPr, w:tr/w:trPr, and w:tc/w:tcPr survive body or page-chrome regeneration. Row text or structural edits rotate the row version; formatting-only edits and moves retain it, copies receive independent IDs, and nested rows or cells are isolated from their outer table. Duplicate or cross-kind identities and unsafe extension branches fail closed, while generated table geometry and formatting win. Imported footnotes and endnotes now retain their native positive w:id across reorderings, while copies receive independent IDs. Signed native comment and reply IDs, reply parentage, and resolved state also survive regeneration. Native DrawingML pictures inside footnotes and endnotes retain their identity, layout, wrapping, crop, and layer metadata through public import and artifact export. Export repairs missing image relationships in generated note parts, allocates collision-free relationship IDs, and validates each media payload. Changed, duplicate, namespace-spoofed, relationship-bound, or semantic drawing branches stay disconnected; generated geometry and media remain authoritative, while legacy VML, shapes, and SmartArt normalize.

Supported native OMML equations now survive as bounded structured objects in the document body, headers, footers, footnotes, and endnotes. Inline and display math, Unicode runs with literal/normal-text semantics, math script/style, manual-break, and alignment-point properties, common fractions, scripts, left-side pre-sub/superscripts with empty script slots, radicals with optional degrees, functions, n-ary operators, combining accents, overbars and underbars, group characters with explicit grouping-character placement and baseline justification, phantoms with visible or hidden bases, independently zeroed width, ascent, or descent, and transparent spacing, border boxes with independently visible edges and four strike directions, semantic boxes with operator-emulation, no-break, differential-spacing, manual-break, and alignment properties, bounded rectangular matrices with explicit column alignment, row-spacing and column-gap rules, and minimum column widths, equation arrays with 1–64 rows, vertical base alignment, maximum/object distribution, row-spacing rules, and & alignment/spacer markers, lower and upper limit objects, and delimiters regenerate as m:oMath or m:oMathPara and render an accessible MathML preview. Bar placement preserves the distinct OMML defaults for an omitted barPr and an omitted pos. Group-character normalization separately preserves an absent chr as U+23DF, an explicitly empty chr, bottom pos, and the absent-versus-empty vertJc defaults. Phantom normalization preserves the visible show default and disabled zeroWid, zeroAsc, zeroDesc, and transp defaults; MathML preview uses mphantom and mpadded without discarding the native spacing properties. Pre-scripts preserve required sub, sup, and e ordering and map empty left script slots to MathML none children after mprescripts. Right-side sSup, sSub, and sSubSup objects enforce their property-first argument order. sSubSupPr preserves alnScr, canonicalizes its absent or disabled value to unaligned scripts, and retains the enabled state through native export. Supported fraction, script, limit, radical, function, n-ary, accent, bar, group-character, phantom, border-box, box, matrix, equation-array, and delimiter property containers preserve one optional ordered m:ctrlPr control format through the same bounded Word run-property model. The control may contain a direct w:rPr or bounded tracked provenance rooted at w:ins, w:del, w:moveFrom, or w:moveTo. Each revision retains a non-negative 32-bit w:id, a bounded w:author, an optional validated w:date, and optional Microsoft 365 w16du:dateUtc with a UTC Z suffix. Word's legal moveFrom/moveTo -> ins/del and ins -> del chains are preserved, with the optional w:rPr at the deepest level. Every supported deg, den, e, fName, lim, num, sub, and sup argument slot preserves the same direct or revision-wrapped control format after its expressions. Empty ctrlPr or direct w:rPr values canonicalize away, while an empty revision remains native provenance. Safe object-control values project only onto separable MathML control/operator nodes; argument-slot formatting and all revision provenance remain native metadata because professional MathML has neither linear-build control characters nor Word review/move-range semantics. Document-level move-range pairing is not inferred from an isolated equation. Matrix properties follow the ordered baseJc -> plcHide -> rSpRule -> cGpRule -> rSp -> cSp -> cGp -> mcs -> ctrlPr grammar. Row and column rules accept single, 1.5, double, exact, and multiple spacing. rSp and cGp are bounded to 65,535, while the minimum column width cSp is bounded to 31,680 twips. If any spacing property is present, omitted or attribute-free peers take their Word defaults and native export emits a complete canonical spacing group. Row spacing and column gaps project to MathML rowspacing and columnspacing; cSp remains native-only for layout because MathML columnwidth is a fixed width rather than Word's minimum. Fractions enforce optional fPr before required num and den arguments. An absent type or an attribute-free type canonicalizes to bar; noBar, skw, and lin remain distinct through native export and MathML projection. Radicals enforce radPr, optional deg, and e ordering. An omitted or empty degree normalizes to a square root, while a visible nonempty degree remains an nth root. Native export emits the canonical radPr -> deg -> e shape and uses degHide=1 with an empty degree slot for square roots. Functions enforce optional funcPr before required fName and e slots. Both required slots may be empty. Every supported CT_OMathArg slot may likewise be empty and follows argPr -> expressions -> ctrlPr. Its optional trailing ctrlPr retains one bounded direct or revision-wrapped Word control; fixed slots use named metadata, while matrix cells, equation-array rows, and delimiter arguments use strictly dimension-aligned metadata. Absent or empty argument/control properties and absent, empty, or zero argSz values normalize to the default. Bounded argSz values from -2 through 2 round-trip as relative argument sizes. The Word-effective box/e, groupChr/e, limLow/lim, limUpp/lim, nary/sub, nary/sup, rad/deg, sPre/sub, sPre/sup, sSub/sub, sSubSup/sub, sSubSup/sup, and sSup/sup pairs project to inverse-sign relative MathML scriptlevel; valid sizes in other argument slots remain native metadata. Out-of-range or malformed sizes, duplicate or misplaced properties, malformed control-revision identities or nesting, and semantic argument properties fail closed. N-ary operators enforce optional naryPr before required sub, sup, and e slots. An omitted chr defaults to U+222B, while an attribute-free chr remains an explicitly empty unsupported operator; an attribute-free limLoc defaults to undOvr. Omitted or disabled grow values normalize to the non-growing default; an attribute-free or enabled grow round-trips and maps to MathML stretchy=true. Native export always emits both limit slots with subHide or supHide for absent scripts. Delimiters require optional dPr before 1–32 e arguments and preserve empty argument slots. Their properties follow begChr -> sepChr -> endChr -> grow -> shp -> ctrlPr; omitted characters normalize to (, U+2502, and ), while attribute-free character properties remain explicitly empty. Omitted or enabled grow and omitted, attribute-free, or centered shapes canonicalize to the growing centered defaults. Non-growing and match shapes round-trip in schema order. MathML projects fixed delimiters with stretchy=false and content-matched growing delimiters with symmetric=false; Word ignores shape while delimiter growth is disabled. Display equations preserve left, right, center, and centerGroup paragraph justification. The bounded native grammar accepts one optional m:oMathParaPr before one m:oMath, while absent properties, absent m:jc, and an attribute-free m:jc all canonicalize to the centerGroup default. Math-run properties preserve the ordered lit, nor, scr, sty, brk, and aln grammar, canonicalize Roman/italic and disabled defaults, bound alnAt to 1–255, and project supported script/style combinations through MathML mathvariant while retaining native break and alignment metadata. Math runs also preserve the native m:rPr -> w:rPr -> m:t/w:t order. The bounded Word run-property subset covers direct and theme font references, Latin and complex-script bold/italic flags, all-caps and small-caps presentation, strike and double-strike, outline, shadow, emboss, imprint, proofing/grid flags, hidden and web-hidden states, direct and theme colors with tint/shade, signed character spacing through 31,680 twips, 1–600% horizontal scaling, half-point kerning thresholds and signed baseline positions, half-point font sizes, colored underline styles, all seven legacy text-animation values, all 27 line-border styles with direct/theme colors, 2–96 eighth-point widths, 0–31 point spacing, and explicit shadow/frame flags, all named highlight colors, complete patterned run shading with direct or theme foreground/background colors, manual run widths from 0 through 31,680 twips with optional signed 32-bit grouping IDs, explicit baseline/superscript/subscript run alignment, all five Word emphasis-mark values (none, dot, comma, circle, and underDot), RTL/complex-script flags, Latin, East Asian, and bidi language tags, and East Asian typography metadata with optional signed 32-bit run IDs, two-lines-in-one flags, all five enclosing-bracket styles, horizontal-in-vertical rotation, and rotated-text compression, plus explicit paragraph-mark always-hidden/reset flags and Office 2010 text glow, shadow, reflection, text-outline, text-fill, 3D-scene, and 3D-property effects. Glow preserves an optional 0 through 2,147,483,647 EMU radius, exactly one RGB or 17-slot theme color source, and up to 64 ordered, repeatable tint, shade, alpha, hue-modulation, saturation, and luminance transform entries. The distinct Office 2010 shadow effect preserves the same color model plus optional 0 through 2,147,483,647 EMU blur and offset coordinates, a direction from 0 inclusive to 360 degrees exclusive, signed horizontal and vertical scales, skew angles strictly between -90 and 90 degrees, and all ten rectangle alignments. Angles retain exact 1/60,000-degree units and scales retain exact 1/1,000-percent units. The leaf Office 2010 reflection effect preserves optional blur and distance coordinates, start/end opacity and position from 0 through 100 percent, direction and fade direction from 0 inclusive to 360 degrees exclusive, signed horizontal and vertical scales, skew angles strictly between -90 and 90 degrees, and the same ten rectangle alignments. Angles retain exact 1/60,000-degree units, while opacity, positions, and scales retain exact 1/1,000-percent units. The structured Office 2010 text-outline effect preserves an optional width from 0 through 20,116,800 EMUs, all three line caps, five compound-line styles, and both pen alignments. Its fill choice remains distinct among none, solid, and gradient fills. Solid fills and optional lists of 2 through 10 gradient stops retain RGB or theme colors and ordered transforms. Gradient shading retains an optional exact linear angle and scale flag or a path shape with an optional signed 32-bit relative fill rectangle. All 11 preset dashes and round, bevel, or miter joins survive, including an optional exact nonnegative miter limit. The Office 2010 text-fill effect reuses the same strict fill grammar without outline geometry. It preserves explicit no-fill, empty or colored solid-fill, and empty or bounded gradient-fill choices, including the same colors, transforms, stop limits, shade geometry, and exact units. The Office 2010 3D scene preserves all 62 camera presets, all 27 light-rig presets, and all eight light directions. Its required camera then light-rig structure remains exact; only the light rig may contain an optional rotation, whose latitude, longitude, and revolution each retain exact 1/60,000-degree units from 0 inclusive to 360 degrees exclusive. The Office 2010 3D properties preserve optional extrusion height and contour width from 0 through 2,147,483,647 EMUs, all 16 material presets, optional top and bottom bevels with independently optional bounded width and height plus all 12 bevel presets, and ordered extrusion and contour RGB/theme colors with the same bounded transform chains. The exact bevelT -> bevelB -> extrusionClr -> contourClr order remains intact. Explicit zero/default geometry values remain present so they can reset inherited formatting. Strict universal font-size and position measures are accepted only when they convert exactly to the bounded half-point model. Strict universal manual widths are accepted only when they convert exactly to bounded whole twips; omitted grouping IDs remain distinct from explicit zero. Explicit baseline alignment remains present so inherited superscript or subscript formatting can be reset; explicit none emphasis likewise removes inherited emphasis marks. Empty w:eastAsianLayout elements canonicalize away, while omitted flags stay distinct from explicit false resets and signed run IDs retain explicit zero. An empty w:specVanish is canonicalized to true; omission remains distinct from an explicit false inheritance reset. An omitted w14:glow/@w14:rad retains the schema default of zero while an explicit zero remains present. Glow export declares the Office 2010 namespace and adds its prefix to mc:Ignorable without replacing existing tokens. Omitted w14:shadow geometry retains its zero/none schema defaults while explicit zero and none values remain present; this effect stays distinct from the legacy w:shadow on/off property. A present empty w14:reflection remains distinct from omission. Its omitted geometry retains zero/none schema defaults while explicit zero and none values remain present. A present empty w14:textOutline also remains distinct from omission and keeps the schema's bevel default. Omitted fill, dash, and join choices retain their defaults, while explicit zero/default attributes and empty child choices remain present. A missing w14:textFill continues to use w:color. A present empty text fill, an empty solid fill, or a gradient without a stop list remains distinct and retains its schema-defined black default. A present empty w14:props3d remains distinct from omission and retains zero extrusion and contour geometry, warm-matte material, and black color defaults. Attribute-free bevels likewise remain present with zero width/height and circle defaults. Explicit on/off values remain distinct, export uses canonical m:rPr -> w:rPr -> m:t, and the MathML preview projects safe direct color, exact transform-free Office 2010 RGB text fills and black fill defaults, background, size, font, direction, language, emphasis, decoration, character spacing, width, effective kerning, baseline-shift, baseline/superscript/subscript alignment, Word emphasis marks, all-caps, and small-caps values without changing source Unicode text. Emphasis marks project as filled dots, a literal comma, or an open circle above the text, or a filled dot below it. Superscript and subscript also project the smaller rendered size required by Word. When w:position and w:vertAlign coexist, both remain in native schema order and the later explicit alignment controls the CSS vertical position. w:em remains after w:rtl/w:cs and before w:lang, while w:eastAsianLayout remains after w:lang, w:specVanish follows it, w14:glow follows w:specVanish, w14:shadow follows w14:glow, and w14:reflection follows w14:shadow, followed by w14:textOutline, w14:textFill, w14:scene3d, and w14:props3d. Simple explicitly sized solid, double, dotted, dashed, inset, and outset line borders project through CSS with direct or automatic color and point padding; explicit nil/none resets also project. Outline, shadow, emboss, imprint, legacy text animations, complex multi-line, wavy, or 3D line borders, border shadow/frame, theme-only border colors, hidden, and web-hidden values remain native-only because Word rendering and view settings govern them. Manual run widths also remain native-only because Word ignores w:fitText inside Office Math, so the MathML preview deliberately does not emulate them. East Asian two-lines-in-one, enclosing brackets, horizontal-in-vertical rotation, and rotated-text compression also remain native-only. CSS text-combine-upright, writing modes, and transforms do not preserve Word's two-sub-line distribution or its left-rotated inline line box, so approximating them would introduce layout drift. w:specVanish also remains native-only and never hides an equation preview. The standard limits its display semantics to paragraph marks and allows it to be ignored on any other run; Word additionally ignores it unless w:vanish is set. Schema-valid values are still retained without inventing that dependency. Office 2010 glow, shadow, reflection, text-outline, 3D-scene, and 3D-property effects also remain native-only. CSS text-shadow, reflection, opacity, perspective, transform, text-stroke, paint-order, and border approximations cannot preserve theme-bound colors, ordered color transforms, exact blur and offset coordinates, reflection opacity/position/fade geometry, signed scaling and skew, rectangle alignment, gradient or compound strokes, preset dashes, caps, joins, or pen alignment, so previews retain readable equation text without inventing a visually misleading effect. Text noFill, theme or transformed text-fill colors, and nonempty gradients remain native-only when no exact MathML color exists. CSS transparent text or background-clipped gradient approximations would make previews fragile, so the underlying readable color remains the fallback. w:highlight takes display precedence over w:shd; named highlights, explicit highlight removal, clear direct fills, solid direct foregrounds, and nil shading map to MathML mathbackground. Pattern masks and theme-only colors remain native metadata when no exact browser color is available. Enabled mutually exclusive all-caps/small-caps, strike/double-strike, or relief combinations, invalid animation values, art-border styles, out-of-range border width/spacing, malformed border colors/flags, missing, malformed, fractional, or out-of-range manual widths and grouping IDs, missing or unknown vertical-alignment or emphasis-mark values, malformed or out-of-range East Asian layout IDs, flags, or bracket styles, malformed paragraph-mark visibility flags, malformed glow radii, shadow or reflection geometry, text-outline fill/gradient/dash/join structure, text-fill wrapper/fill/gradient structure, color choices or transform chains, 3D-scene camera/light structure, 3D-property extrusion/contour/bevel/color structure, bounded coordinates, preset values, directions, or rotation angles, and unknown, duplicated, reordered, namespace-spoofed, or relationship-bound Word run properties fail closed instead of being silently discarded. Border-box, box, and equation-array flags retain their semantic defaults, and manual-break alignment indices are bounded to 1–255. Strict and transitional UTF-8/UTF-16 math is normalized for editing. Invalid or non-combining accent characters, malformed math-run or function structures, invalid or contradictory fraction, radical, n-ary, delimiter, bar, group-character, phantom, border-box, box, or equation-array properties, malformed script-property, pre-script, math-paragraph, or lower/upper limit structures, malformed, duplicated, reordered, or out-of-range matrix spacing/gap properties, ragged or over-limit matrices, over-limit equation arrays, malformed, misplaced, over-budget, namespace-spoofed, nested, or relationship-bound math is flattened to bounded text and reported instead of being trusted or silently attached to another equation. Relationship-free passive extensions on uniquely matched w:footnote, w:endnote, w:comment, and w15:commentEx roots are retained, and valid commentsIds durable IDs are rebound to each regenerated final comment paragraph. Duplicate or namespace-spoofed identities, deleted semantic records, relationship-bound branches, and unsupported modern reaction/people sidecars fail closed. Within uniquely matched note, comment, and reply records, text-stable direct paragraphs and runs retain eligible passive extensions on w:p, w:r, and w:rPr. Safe unmodeled note properties also survive, while unchanged plain-text comments recover relationship-free source run boundaries and formatting. Stable w:hyperlink wrappers now retain safe tooltips and passive metadata. Generated note destinations remain authoritative; unchanged comments and replies recover validated HTTP(S), mailto, or internal-anchor destinations, with external relationship IDs deduplicated or rewritten after collisions. Text-stable static rich-text and plain-text content controls also recover eligible inline or contiguous block wrappers, aliases, tags, locking, signed IDs, Word 2013 appearance and color, end-character formatting, passive metadata, and stable runs. Editable footnote and endnote tables now regenerate as native w:tbl blocks rather than flattened row text. Rich-text block controls can safely span structurally stable paragraphs, tables, and nested tables; matching includes row/cell shape, grid spans, merge state, nested block shape, and exact paragraph text while generated table geometry wins. Colliding control IDs are rewritten while unconflicted source IDs remain stable. Text or table-structure edits, duplicate paragraphs or properties, missing or malformed hyperlink relationships, wrong target types or modes, unsafe or relative targets, combined external-plus-anchor destinations, namespace spoofing, active data bindings or placeholder state, form or nested controls, relationship-bound content, math, drawing-bearing control wrappers, and other unsupported wrappers fail closed or normalize instead of being attached to the wrong content. Source font-table metadata and source-only internal obfuscated font payloads are also retained, with relationship references rewritten after ID collisions. External fonts, wrong relationship or content types, duplicate identities, and paths that collide with generated payloads are not reconnected. Native DOCX consumers can use the retained embedded fonts; the browser editor, preview, and PDF renderer do not load document-embedded font binaries and may substitute fonts or wrap text differently.

The repository also contains a native Rust engine for deterministic reads, validation, mutation, batch operations, exact natural-unit inventories, sibling-isolated semantic previews, screenshots, file watching, and a source-bound exact-layout raster boundary across Office packages. The first layout-authoritative route supports image-only PPTX slides whose single opaque PNG exactly covers the declared slide surface. The optional Rust pdfium feature adds bounded, one-based PDF page inventory and exact page PNGs through an explicit host-supplied PDFium 7881 library. It records media/crop boxes, rotation, physical and pixel geometry, source and engine hashes, and never downloads a runtime or introduces a Browser dependency. Consumers can inspect selected pages from one previously validated complete inventory without rescanning the full document; render still revalidates the immutable source and actual page profile before publication. The same retained inventory now authorizes bounded native PDF text-layer extraction with source-order Unicode, exact UTF-8/UTF-16 ranges, optional glyph boxes, and PDFium-native same-line, same-style runs with exact PDF-coordinate bounds. Independent character and run limits keep the result bounded. Document outlines retain exact page targets. Text and outline calls revalidate the immutable source, reuse inventory authority, and return typed limit or unsupported failures without OCR or Browser access. Richer slides and formats without an authoritative provider remain typed unsupported instead of being relabeled semantic previews. Native DOCX and PPTX table reads also normalize merged cells into one-based logical row and column coordinates, row and column spans, and stable anchor references for covered physical cells.

# Run from the repository root
cargo run -p a3s-office-cli -- validate report.docx --json
cargo run -p a3s-office-cli -- view report.docx outline --json
cargo run -p a3s-office-cli -- set report.docx /body --find Draft --replace Final --json

# Start the standard MCP server
cargo run -p a3s-office-cli -- mcp

CLI, MCP, the typed Rust API, and the packaged Office Skill share the same bounded contracts. They inspect and modify files without launching desktop Office or scraping editor UI.

Read the native engine design, the complete CLI reference, or the published CLI and Skill guide.

The browser plane combines controlled editor surfaces, framework adapters, Workers, Rust WebAssembly, and PDFium. The native plane keeps filesystem and OOXML package concerns in a separate Rust core, with a host-injected optional PDFium provider for read-only PDF page evidence. Both planes expose typed contracts; neither requires an A3S backend.

For engine ownership, Worker/WASM boundaries, delivery stages, and performance gates, see Browser editor architecture.

A3S Office is pre-1.0. Content models and component props are public, but a minor release may still include breaking model changes. Required migrations will be called out in the changelog.

The project targets predictable browser editing and file preservation, not pixel parity with every Microsoft Office or WPS feature. Unsupported OOXML semantics and fidelity gaps remain explicit compatibility boundaries instead of being silently approximated. Track product depth and release evidence in the editor quality roadmap.

Run focused checks from the repository root:

bun install --frozen-lockfile
bun run format:check
bun run lint
bun run typecheck
bun run test
bun run build

Start the integration Playground with bun run playground. The full pull request checklist also covers the Rust workspace, browser bundle budget, and committed visual contracts; see CONTRIBUTING.md.

The published website keeps the interactive Playground at its root and builds the searchable Rspress documentation center under /docs/. Simplified Chinese is the stable default, English remains available from the language menu, and the version menu switches between latest and frozen release documentation. Search is scoped to the active language and version. Both surfaces use the same deployment base, so preview, Pages, and fork deployments keep working without hard-coded return URLs.

• Live Playground
• Documentation center
• A3S Office 0.3.0 documentation
• A3S Office 0.2.0 documentation
• A3S Office 0.1.0 documentation
• React, Vue, and Web Component integration
• Office CLI and coding-agent Skill
• Browser editor architecture
• Native Office engine
• CLI reference
• Editor quality roadmap
• Changelog

Contributions are welcome. Read the contribution guide and Code of Conduct before opening a change. Report suspected vulnerabilities through the private process in SECURITY.md, not through a public issue.

A3S Office is available under the MIT License. Bundled PDFium and other third-party assets carry additional notices in THIRD_PARTY_NOTICES.md.