CAIT

Computer-aided translation, inside DeepSeek Harness.
Translation memory · glossary · segment editor · MT assistance · document tabs · Office / subtitle / localization formats

简体中文 · 日本語 · English

CAIT adds a CAT workbench to the DSH Web UI and Desktop. It opens from a left-sidebar entry, keeps one shared store behind the workbench and seven agent tools, and covers the practical path from importing a source file to exporting a translated document.

Tested with DSH 0.2.2-rc.1. CAIT uses DSH's own model routes and credentials; it never asks for an API key. The internal fallback provider is still called mock, but the UI labels it Glossary substitution (offline).

Why CAIT

Native to DSH	A real sidebar panel, a main workbench, DSH theme tokens, and the same store for humans and agents. No iframe, no separate app.
TM that explains itself	Multiple TM libraries, mounted-only lookup, exact / near-exact / high / medium / low fuzzy grades, and automatic write-back on confirm.
Glossary-aware editing	Multiple term bases, source-language filtering, inline highlighting, click-to-insert terms, and per-term case sensitivity.
A document workflow	Tabs, close/reopen, recent-document cleanup, duplicate-import reuse, and progress per document.
Real format coverage	TXT, Markdown, DOCX, EPUB, TMX, CSV, SRT/VTT, PO, XLIFF 1.2/2.0/SDLXLIFF, HTML, JSON, XLSX, PPTX, and RTF.
Agent-ready	Seven tools share the open document and store, so an agent can translate alongside you.

Quick start

1. Install CAIT and open it from the CAIT row in the left sidebar.
2. Choose New page, then drop a source file or paste text.
3. Set the source and target languages.
4. Translate the current segment; the right panel shows TM matches, glossary hits, and an MT suggestion.
5. Confirm & next writes the pair to the default mounted TM.
6. Export target-only, bilingual, or a format-preserving document.

Typing in the editor is a draft and stays in memory. Confirming a segment (or an explicit structural change) writes the snapshot. The open workbench polls the Host revision every two seconds, so changes made by an agent appear without a manual reload.

Features

Translation memory

• Multiple TM libraries with id, name, mount state, and a default write library.
• Exact, near-exact, and three fuzzy bands:
  • near_exact compares a key that ignores digits, punctuation, and whitespace; it does not depend on a score cutoff.
  • high_fuzzy is >= 0.85, medium_fuzzy is 0.75–0.85, low_fuzzy is below 0.75 (above the configurable floor, default 0.55).
• Fuzzy scoring is lexical: 72% character-bigram Dice + 28% token Jaccard. Latin text uses words; CJK text uses individual characters. There is no stemming, synonym, or semantic matching.
• Lookups only see mounted libraries. cat_submit_translation accepts an optional targetTmId; an unmounted target is rejected with TM_NOT_MOUNTED.
• bootstrap().tm.entries is a 40-entry preview of mounted entries; bootstrap().tm.count is the mounted count and bootstrap().tm.total is the all-library count. Use cat_lookup_tm or the library modal for full data.
• TMX 1.4 <tu>/<tuv>/<seg> import/export. Inline TMX placeholders are flattened to plain text with an explicit warning.

Glossary

• Multiple glossary libraries with mount state and a default write library.
• Live source highlighting and click-to-insert term chips.
• CSV/TSV import, per-term notes, source-language filtering, and a caseSensitive flag honored by both the workbench and cat_lookup_glossary.
• Language codes are canonicalized (EN → en, ZH_cn → zh-CN).

Workbench

• Paragraph/sentence segmentation with a per-segment target editor.
• Draft saving, confirm-and-next, previous/next navigation, and progress.
• Document tabs; closing a tab does not delete the document.
• Open existing document reopens a closed document.
• Interface language switch in Settings → Interface: Follow DSH language (default), 简体中文, English, or 日本語. It applies to the workbench and the sidebar label right away, and changes only the CAIT UI — never the document's source or target language.
• The trash dialog beside the picker deletes one closed document or all closed documents; deletion is permanent and does not touch TM, glossary, or other documents.
• Re-importing identical content in the same format reuses the existing document instead of creating a duplicate. The fingerprint covers languages, source, format, and exchange metadata.
• Responsive density: the workbench measures its DSH panel and applies a --cait-u multiplier of 1×–1.8×. A 1600×900 panel renders at ~1.32× and a 2560×1440 panel at 1.8×; short windows stay at 1× rather than shrinking.

Preprocessing

Imported source text passes through a preprocessing stage before segmentation:

• Collapse repeated spaces and tabs, trim indentation, and merge consecutive blank lines.
• Remove zero-width characters and stray control characters.
• Placeholder tokens ({1}, {2}, …), punctuation, casing, and paragraph order are left untouched, so XLIFF/HTML/EPUB inline markup still round-trips.
• The three steps are independently switchable in Settings → Preprocessing and are persisted with the other settings. They apply to new imports and createDocument calls; existing documents are not rewritten.

MT assistance

CAIT does not own an endpoint or key. The selector is built from DSH:

• ctx.llm.listProviders() supplies registered provider routes.
• ctx.loader.entries() is consulted for config.providers when available.
• ctx.llm.listModels(provider) supplies model ids; CAIT selects the first model by default.
• ctx.llm.stream({ provider, model, messages, temperature, purpose: 'cait-mt' }) performs the call; CAIT concatenates text-delta chunks.

If no usable route exists, the selected route disappears, or it has no models, CAIT falls back to offline glossary substitution and says so in the UI and in the cat_suggest_mt result. Stream failures are logged in the Host with provider/model/code/status; the client receives only MT_PROVIDER_FAILED.

Supported formats

Format	Import	Export	Notes
TXT / Markdown	✅	✅	Paragraph and sentence segmentation
CSV	✅	✅	Comma, semicolon, tab, or pipe delimiter auto-detected; source/target column by header name or 1-based number; existing bilingual export
DOCX	✅	✅	Body paragraphs; table blocks are excluded from import. Export patches the original package, keeping styles, numbering, images, headers, tables, and layout.
EPUB	✅	✅	EPUB 3 spine order; XHTML text blocks with inline markup kept as tokens and patched back into the retained package. DRM-protected, fixed-layout, and scripted EPUBs are not supported.
TMX 1.4	✅	✅	Common <tu>/<tuv>/<seg> subset; inline markup flattened with warning
SRT / WebVTT	✅	✅	One cue per segment, timings/settings/identifier retained; semantic tags kept; invalid ranges rejected
PO	✅	✅	Contexts, plural forms, translator comments, obsolete #~ entries
XLIFF 1.2	✅	✅	Inline tags become {n} tokens; missing tokens block confirmation
XLIFF 2.0	✅	✅	Basic <unit><segment><source>/<target> subset
SDLXLIFF	✅	✅	Basic XLIFF 1.2 path; SDL-specific extensions are not round-tripped
HTML	✅	✅	Text blocks and inline tags preserved; document CSS/layout is not rebuilt
JSON	✅	✅	String-path subset; object/array structure preserved via a template; keys and numbers are not translated
XLSX	✅	✅	First worksheet; Source/Target headers or columns A/B; export is a new two-column workbook
PPTX	✅	✅*	Source-preserving export; requires the imported .pptx package. Body text only; notes/charts/SmartArt not imported.
RTF	✅	✅	Basic paragraphs, \uN, \'hh, control words; original styling not round-tripped

* PPTX export fails with PPTX_SOURCE_REQUIRED when the retained source package is missing rather than silently producing an unformatted deck.

Exchange metadata (subtitle timings, PO contexts/plurals/comments, XLIFF ids and inline token maps, JSON paths/templates, XLSX rows, PPTX slide/paragraph positions, EPUB spine hrefs and block indexes) is stored on the document/segments and persists in the snapshot.

PDF is not supported

CAIT does not import PDF, and future releases will not add PDF support. PDF is a fixed-layout print format: it has no logical paragraphs, reading order, or inline markup. Text extracted from it is fragmented across drawing operations, loses headings, tables, and inline emphasis, and produces segments that are poor input for translation memory and MT — in other words, PDF is extremely unsuitable for AI-related work.

To translate PDF content, convert it to a supported format first, for example:

pandoc input.pdf -t docx -o output.docx   # or -t html, -t markdown

Adobe Acrobat's Export to Word/HTML, LibreOffice, or any other converter that produces DOCX, HTML, EPUB, or plain text works too. Scanned PDFs need OCR before conversion; CAIT has no image OCR stage.

Install

CAIT installs as a DSH bundle; the published package name is dsh-cait and the plugin itself shows up as CAIT in the left sidebar. The in-app plugin manager owns the desktop profile, so use it rather than editing the profile's package.json.

From npm

In DSH Desktop (or any profile with the plugin_manager tool):

plugin_manager install_bundle target: dsh-cait

Pin a release with dsh-cait@1.0.5, or ask for the newest one with dsh-cait@latest. The manager resolves the registry package, applies the bundle patch, and activates the plugin — no hand-written profile rows.

With a CLI-managed profile:

dsh plugin --profile web add dsh-cait

Replace web with your profile name, and restart dsh web if your host requires it.

From this repository

GitHub:

plugin_manager install_bundle target: github:JoviLecca/dsh-CAIT

Local checkout:

plugin_manager install_bundle target: /absolute/path/to/dsh-CAIT

Then reload DSH. The CAIT entry appears in the left sidebar.

From source

git clone <this-repository> dsh-CAIT
cd dsh-CAIT
npm run build:client

For a local --patch overlay, add a row pointing at this directory:

# _dev/cait.patch.yml
- insert:
    - id: cait-dev
      name: 'C:\absolute\path\to\dsh-CAIT'

dsh web --patch C:\absolute\path\to\dsh-CAIT\_dev\cait.patch.yml

--patch is a launcher option; place it after the app name (web) and before any app arguments. Use either the overlay or the installed bundle in a profile, not both.

Configuration

Option	Default	Meaning
dataDir	""	Directory for store.json and sources/. Empty means $DSH_HOME/cait. Absolute, relative, and ~/... paths are accepted.

- id: dsh-cait
  name: dsh-cait
  config:
    dataDir: 'D:\CAT\cait-data'

The snapshot stores documents, open tabs, TM, glossary, libraries, mounts, and non-secret settings. Imported DOCX/PPTX/EPUB source packages live in sources/.

In-app settings (Settings) live in the snapshot rather than in the YAML above: source/target language, fuzzy threshold, TM result limit, MT route/model/temperature, and the interface language (uiLang: auto | zh | en | ja, default auto = follow the DSH locale). Segment confirmations use a strict write: if the snapshot cannot be written, the confirm fails with PERSISTENCE_FAILED (503) and rolls back the in-memory confirmation. Other structural edits remain best-effort and surface bootstrap().storage.error in the workbench banner.

If the snapshot is corrupt or has an unknown version, CAIT logs a warning, moves it to store.json.corrupt-<timestamp>, and starts empty instead of failing activation. Version-1 snapshots are migrated to version 2 with default TM and glossary libraries.

Agent tools

Tool	Purpose
cat_get_segment	Current segment with TM matches and glossary hits
cat_submit_translation	Confirm a target, write to a mounted TM (optional targetTmId), advance
cat_lookup_tm	Graded TM lookup across mounted libraries
cat_lookup_glossary	Query mounted glossaries; honors caseSensitive
cat_list_documents	List documents and progress
cat_switch_document	Select the active document
cat_suggest_mt	MT via the selected DSH route, or the explicit offline fallback

The workbench and tools share one CatStore, so an agent can translate the same document the user has open.

Architecture

flowchart LR
  UI["DSH Web UI<br/>(sidebar + workbench)"] --> Client["client.js<br/>generated Web bundle"]
  Client --> API["/cait/api/rpc<br/>same-origin JSON"]
  Tools["7 agent tools"] --> Store["CatStore"]
  API --> Store
  Store --> Snapshot[("store.json<br/>+ sources/")]

• Host (index.js, lib/) owns the store, persistence, import/export, tools, and the private API.
• Client (client/) is plain React loaded through DSH's module loader and rendered into sidebar.panellist and main. It styles only with --dsw-alias-* tokens.
• client.js is generated; edit client/*.js and run npm run build:client.

Project layout

cait/
├─ package.json
├─ cordis.patch.yml
├─ index.js                 # Host half
├─ client.js                # generated Web bundle
├─ client/                  # helpers, styles, RPC, components, locales, entry
├─ scripts/build-client.mjs
├─ icon.svg
├─ locale/{en,zh,ja}.json
├─ NOTICE
├─ README.md
├─ README.zh-CN.md
├─ README.ja.md
├─ CHANGELOG.md
├─ lib/
│  ├─ store.js              # CatStore facade + document/segment core
│  ├─ errors.js
│  ├─ store-utils.js
│  ├─ libraries.js          # TM/glossary registries + mounts
│  ├─ tm.js
│  ├─ glossary.js
│  ├─ persistence.js
│  ├─ import-export.js
│  ├─ formats.js            # CSV/SRT/VTT/PO/XLIFF/HTML/JSON/RTF
│  ├─ html.js               # Shared HTML/XHTML run scanner + patcher
│  ├─ epub.js               # EPUB package read / spine import / patch export
│  ├─ preprocess.js         # Import-time source cleaning stage
│  ├─ xlsx.js
│  ├─ pptx.js
│  ├─ segmenter.js
│  ├─ similarity.js
│  ├─ tmx.js
│  ├─ docx.js
│  ├─ markdown.js
│  ├─ xml.js
│  ├─ mt.js
│  ├─ tools.js
│  └─ api.js
└─ _dev/                    # tests, fixtures, local patch overlay

Development

Requires Node.js 22+ and DSH 0.2.x. Tested with DSH 0.2.2-rc.1 and Node 26.7.0.

npm run build:client
node --check client.js

node _dev/test-core.mjs
node _dev/test-imports.mjs
node _dev/test-formats.mjs
node _dev/test-epub.mjs
node _dev/test-preprocess.mjs
node _dev/test-second-tier.mjs
node _dev/test-docx-export.mjs
node _dev/test-api.mjs
node _dev/test-plugin.mjs
node _dev/test-persistence.mjs
node _dev/test-documents.mjs
node _dev/test-libraries.mjs
node _dev/test-mounts.mjs
node _dev/test-ui-scale.mjs
node _dev/test-mt.mjs

The import/export fixtures are _dev/sample.docx, _dev/sample-table.docx, and _dev/sample-format.docx; regenerate them with the matching python _dev/make-*.py scripts. All 15 suites should pass.

Releasing

npm publish runs prepublishOnly, which rebuilds client.js from the client/ fragments and syntax-checks the result, so a release cannot ship a stale bundle. Publishing from the repository root:

npm publish

.github/workflows/publish.yml does the same from CI on a published GitHub release, using npm Trusted Publishing (OIDC) instead of a stored token, and it refuses to publish when the release tag does not match package.json.

The very first release has to be published locally, because a trusted publisher can only be configured for a package that already exists:

npm login
npm publish

Afterwards open the package on npmjs.com, go to Settings → Trusted publishing, and add the repository JoviLecca/dsh-CAIT with the workflow file publish.yml. Later releases can then be published from GitHub with a release.

Security model

• The Host API is mounted at /cait/api, restricted to same-origin/trusted requests by ctx.connection.requestRejection.
• RPC bodies are JSON, capped at 32 MB, and return 413 BODY_TOO_LARGE beyond that.
• clearTM / clearGlossary require params.confirm === true in addition to the browser trust check; the UI asks before sending it.
• CAIT never receives, stores, or returns an API key. DSH credentials stay inside the selected provider adapter.
• Persistence is one snapshot with last-write-wins semantics; it is not a multi-user journal.

Known limits and roadmap

• No PDF import; PDF is intentionally out of scope (see PDF is not supported). No image OCR yet.
• EPUB import follows the spine and body XHTML text blocks; DRM-protected, fixed-layout, scripted, and MathML-heavy books are not supported.
• DOCX import skips tables, headers, footnotes, fields, alt text, and tracked deletions. DOCX export leaves those regions in the source language.
• Mixed-run DOCX/PPTX paragraphs inherit the first run's formatting.
• PPTX import covers body text, not notes, charts, or SmartArt.
• XLSX import/export is a two-column table; cell styles, formulas, merged cells, images, and extra sheets are not preserved.
• HTML/RTF export does not round-trip original styling; JSON translates string values only.
• TM matching is lexical, not semantic; no stemming, synonyms, or embeddings.
• Library rename/delete and per-tab mount state are not implemented yet.
• The workbench UI ships in Chinese, English, and Japanese, switchable in Settings; this README ships in English, Simplified Chinese, and Japanese, and the English version is the source of truth.

Planned next: image/vision input through a multimodal DSH route, richer library management, style-preserving XLSX output, and XLIFF <alt-trans> / notes support.

Changelog and versioning

See CHANGELOG.md. v1.0.0 was the first public release; v1.0.1 adds the Japanese UI and the in-app interface language switch, v1.0.2 makes Follow DSH language honour the DSH locale, v1.0.3 publishes the package to npm, v1.0.4 moves later releases to the provenance-publishing workflow, and v1.0.5 adds EPUB, import preprocessing, and the PDF policy. The project was developed as 0.1.0 and renumbered for the GitHub release.

License: Apache License 2.0 — see LICENSE. Redistributions must retain the attribution in NOTICE.