dsh-document

A DeepSeek Harness plugin bundle (@jiaoqsh/dsh-document) that gives the model a read_document tool: Word, PowerPoint, Excel, OpenDocument, RTF, EPUB, CSV, and PDF files are converted to line-numbered Markdown the model can page through with offset/limit.

Conversion runs locally: office formats through @firecrawl/anydoc (Rust core, Node bindings) and PDFs through @firecrawl/pdf-inspector (WASM build, run in a worker thread) — no API key, no network, no external binaries; both MIT. PDFs get page selection, <!-- Page N --> markers, and page facts: total pages, text-based / scanned / mixed, and which pages have no extractable text. Files are read through the harness ctx.fs seam, so whatever filesystem provider and sandbox policy a deployment mounts applies unchanged.

Install

Into an existing profile (web, headless, or your own):

dsh plugin --profile web add github:jiaoqsh/dsh-document#<commit-sha>

pnpm ≥ 10 refuses to run a git dependency's prepare script until you allow it; the first add fails and prints the exact key to copy into the profile's pnpm-workspace.yaml ($DSH_HOME/profiles/<name>/pnpm-workspace.yaml). The key names the resolved tarball, so a bare package name does not match:

allowBuilds:
  '@jiaoqsh/dsh-document@https://codeload.github.com/jiaoqsh/dsh-document/tar.gz/<commit-sha>': true

Re-run the add. Allowing the build means executing this package's prepare (a tsdown transpile of src/) on your machine at install time; pin a commit so a later push cannot change what runs. A packed tarball (pnpm pack → dsh plugin add ./jiaoqsh-dsh-document-<version>.tgz) needs no allowance.

dsh plugin prints "missing peer" warnings for the @deepseek-ai/* packages: expected. The dsh installation supplies them at runtime; profiles deliberately do not install peers.

Verify, then boot:

dsh --profile web --dump-config   # shows a "# == @jiaoqsh/dsh-document" layer
dsh --profile web

Remove with dsh plugin --profile web remove @jiaoqsh/dsh-document.

From a source checkout of the harness

pnpm dsh web --patch /absolute/path/to/dsh-document/overlay.yml

where the overlay inserts the built entry by absolute path:

- insert:
    - id: document-tools
      name: '/absolute/path/to/dsh-document/lib/index.js'

Configuration

The bundle's layer inserts one row, document-tools, with schema defaults. Override it by id in your profile's cordis.patch.yml; a patch replaces the whole config, so restate every key you need:

- id: document-tools
  config:
    maxInputBytes: 104857600   # 100 MiB
    readLimit: 2000
    maxLineLength: 2000
    maxOutputBytes: 51200
    pdfMaxPages: 100
    pdfProfile: fidelity

Key	Default	Meaning
maxInputBytes	52428800 (50 MiB)	Inclusive byte cap on the source file. Enforced by the filesystem provider before any bytes are buffered; larger files are refused.
readLimit	2000	Default and maximum number of Markdown lines returned by one call.
maxLineLength	2000	Maximum characters per returned line; overflow is cut with … [line truncated].
maxOutputBytes	51200 (50 KiB)	Maximum bytes of line text returned by one call; the window stops early and the footer says how to continue.
pdfMaxPages	100	Maximum distinct pages one pages selection may name.
pdfProfile	fidelity	PDF Markdown profile: fidelity keeps source structure, compact spends fewer tokens.

Every numeric value must be a positive integer and pdfProfile one of the two names; anything else fails the plugin load with a message naming the key.

The tool

read_document(file_path, offset?, limit?, pages?)

• file_path — resolved by the filesystem backend; relative paths resolve against the calling session's workspace.
• offset — 1-based first line of the converted Markdown (default 1).
• limit — lines to return (default and maximum readLimit).
• pages — PDF only: 1-based pages to convert, as numbers and ranges like "1-3,7" (at most pdfMaxPages). Default: every page. Naming a page beyond the last one is an error that states the page count.

Supported extensions: .pdf, .doc, .docm, .docx, .ppt, .pps, .pot, .pptx, .pptm, .ppsx, .ppsm, .xls, .xlsx, .xlsm, .xlsb, .odt, .ods, .odp, .rtf, .epub, .csv. The format comes from the extension, never from content sniffing (CSV has no signature).

Canonical value (what Code Mode receives):

{ path: string, format: 'pdf' | 'docx' | ..., offset: number,
  lines: { number: number, text: string }[], totalLines: number, truncatedByBytes: boolean,
  pdf?: { pageCount: number, kind: 'text' | 'scanned' | 'image' | 'mixed',
          pagesNeedingOcr: number[], pages?: number[], title?: string } }

Model-facing text (a PDF, pages 2 and 4 of 5):

<path>/work/report.pdf</path>
<format>pdf</format>
<pdf>5 pages, text-based; showing pages 2, 4</pdf>
<content>
1: <!-- Page 2 -->
2: 
3: Revenue grew 12% year over year.

(Showing lines 1-3 of 8. Use offset=4 to continue.)
</content>

A mixed PDF adds <warning>Pages 3, 7-8 contain no extractable text (scanned or image content); their content is missing below and would need OCR.</warning> before <content>. Non-PDF formats omit the <pdf> line.

Failures are tool errors in model terms: unsupported extension (pointing at read for plain text), pages on a non-PDF, a malformed pages value, not found, not a regular file, over maxInputBytes, encrypted, damaged or incomplete, engine resource limit, a page beyond the last page, cancellation, or no extractable text (a scanned or image-only PDF says so and that OCR is needed; this tool performs no OCR).

Model Experience

System prompt section tool:read_document

What the model sees

One fixed sentence, order 100 beside the shipped tool:read guidance:

Use the read_document tool — not read or shell commands — to inspect PDF, Word, PowerPoint, Excel, OpenDocument, RTF, EPUB, and CSV files. It returns the document converted to line-numbered Markdown; use offset and limit to continue reading long documents. For a PDF, pass pages (for example "1-3,7") to read only those pages; page markers like <!-- Page 4 --> show where each page starts.

Token effect

Fixed: the section and the tool schema add a constant number of tokens to every request; results add up to maxOutputBytes per call.

KV Cache effect

Prefix-stable: the section text and schema never change between requests, so they do not invalidate a cached prompt prefix.

Known Limitations and Deferred Work

• No OCR — pages without a text layer are reported (pagesNeedingOcr, the <warning> line) but not read; a fully scanned or image-only PDF is an error naming the cause.
• PDF conversion runs in a fresh worker thread per call — cancellation terminates it, and the harness event loop stays free, at the cost of ~50 ms of WASM start-up per call. Office-format conversion (anydoc) runs on the libuv thread pool and cannot be cancelled once started; maxInputBytes is its bound.
• Layout-heavy PDFs may collapse paragraphs into long lines (then cut by maxLineLength); pdfProfile: compact trades structure for tokens.
• Engines are fixed — the DocumentConverter interface and routeConverters in src/converter.ts are the seam for a hosted or OCR-capable engine; none is wired today.
• The pdf-inspector native binary is not used — its npm build ships no darwin-x64 binary, so the WASM build runs everywhere for one code path.

Development

pnpm install          # also builds lib/ via prepare
pnpm run typecheck
pnpm test             # real Cordis Context + real registry + real local fs; no API key
pnpm run build

Fixtures under tests/fixtures/ were generated once with macOS textutil and cupsfilter (including a five-page PDF and an image-only PDF) and are committed so the suite runs anywhere. In source mode the PDF worker is spawned as .ts with --experimental-strip-types, so it stays free of TypeScript-only runtime syntax.

License

MIT