dsh-file-convert

Local-first file conversion for DeepSeek Harness.

Convert images, PDFs and data files directly inside your DSH agent sessions — no API keys, no uploads, no servers, no token cost for the conversion itself. Files never leave your machine.

Unofficial community plugin. Not affiliated with or endorsed by DeepSeek.

Compatibility: v0.4.5+ targets DeepSeek Harness 0.1.5-rc.2 and its canonical-output tool API. Node.js ^22.19.0 || >=24.0.0 is required.

Why

Agents constantly need file conversions: "turn this PDF into images", "give me that JSON as YAML", "convert all JPGs in this folder to WebP". Instead of shelling out or pasting data around, dsh-file-convert gives your agent seven purpose-built tools backed by battle-tested local libraries.

• ✅ Local execution — files never leave the machine
• ✅ No API key, no server, no conversion tokens
• ✅ Natural language friendly — the agent calls the tools, you just ask
• ✅ Batch conversions with a compact summary
• ✅ Honest failures — missing dependency, unsupported pair, existing output: every error says exactly why
• ✅ Images, PDF and data need zero external binaries — prebuilt npm packages only. Media needs one tool (ffmpeg), clearly reported when missing

Supported conversions

26 conversions. Images, PDF and data work out of the box via npm install. Optional tools unlock the rest, each clearly reported by list_conversions when missing:

• FFmpeg -> media rows. Install it system-wide (preferred for untrusted media), or ask the agent to run install_media_dependencies — it downloads pinned current builds (FFmpeg 6.1.1, ~56 MB total, one time) into the plugin cache, sha256-verified, from the npmmirror binary CDN with the GitHub release as fallback.
• LibreOffice -> DOCX/PPTX/XLSX to PDF. winget install TheDocumentFoundation.LibreOffice / brew install --cask libreoffice / apt install libreoffice.
• Ghostscript -> PDF compression in optimize_file.
• Python + pdf2docx -> the experimental PDF to DOCX row (pip install pdf2docx).
• Tesseract (optional) -> faster OCR for scanned PDFs; without it the bundled tesseract.js is used and its language data is fetched explicitly via install_ocr_dependencies (winget install UB-Mannheim.TesseractOCR).

Install

Inside a DSH profile — three ways, easiest first:

# 1. from npm (once published)
dsh plugin --profile default add dsh-file-convert

# 2. straight from GitHub (a `prepare` build runs; allow it once)
dsh plugin --profile default add github:zzy-12345678/dsh-file-convert

Git installs may ask you to allow the build step in the profile's pnpm-workspace.yaml:

First-install note: pnpm may also ask you to decide on a build script for tesseract.js (it only shows a donation notice — skipping is safe). Set it in the same file and re-run the install:

allowBuilds:
  tesseract.js: false

allowBuilds:
  dsh-file-convert: true

From a local checkout (e.g. while hacking on it):

git clone https://github.com/zzy-12345678/dsh-file-convert
cd dsh-file-convert && npm install && npm run build
dsh plugin --profile default add /absolute/path/to/dsh-file-convert

Then restart DSH (dsh web or your usual entry point). All seven tools appear automatically.

The seven tools

convert_file

Convert one file.

{ "input": "/tmp/report.pdf", "output_format": "png", "dpi": 200 }

Converted: /tmp/report.pdf (pdf) -> /tmp/report.png (png)
1.2 MB -> 431.0 KB in 1.4s

• Default output: next to the input file, same base name, new extension.
• Multi-page PDFs produce <name>-<page>.<ext> for every page; pages: "1-3,5" selects pages (outputs keep their real page numbers, text joins only the selection).
• Scanned PDFs → TXT: ocr: true (optionally ocr_lang, default chi_sim+eng) recognizes the rendered pages instead of the text layer. Engine priority: a local Tesseract CLI, then the bundled tesseract.js (whose language data is never downloaded implicitly — run install_ocr_dependencies first, about 10-30 MB per language).
• Existing outputs are refused unless overwrite: true.
• Options: output, overwrite, quality (1–100), dpi (PDF/SVG rasterization), pages, ocr, ocr_lang.

batch_convert

Convert every matching file in a directory (top level).

{ "input_dir": "/home/me/Pictures", "output_format": "webp" }

Batch convert in /home/me/Pictures -> WEBP
Converted: 18, skipped: 2, failed: 0
Output dir: /home/me/Pictures/output

• input_format filters by source format; omit it to auto-detect every convertible file.
• output_dir defaults to <input_dir>/output.
• Existing outputs are skipped (not overwritten) unless overwrite: true.

inspect_file

Facts before action, detected from file content — not just the extension:

{ "input": "/tmp/scan.pdf" }

{ "kind": "pdf", "pages": 24, "encrypted": false, "likelyScanned": true, "bytes": 13000000 }

optimize_file

Shrink a file toward a target size instead of converting it:

{ "input": "video.mp4", "target_size_mb": 20 }

Optimized: video.mp4 (mp4) -> video-min.mp4
18.3 MB -> 19.7 MB (target 20 MB) in 41.2s
Applied: two-pass x264: video 512k + audio 128k over 185.0s

• MP4/MOV: two-pass x264, the video bitrate is computed from the target (audio 128k, dropping to 64k for tight targets); output is always MP4. Requires ffmpeg + ffprobe.
• JPG/WEBP: binary-searches the highest encoder quality that fits; PNG uses palette reduction. No external tools needed.
• PDF: Ghostscript quality presets (printer/ebook/screen), first preset that fits the target wins; requires Ghostscript.
• Targets below what the codec can physically reach are refused with the achievable minimum.
• GIF optimization is not supported yet.

install_media_dependencies

One-call media setup: downloads pinned FFmpeg 6.1.1 static builds (ffmpeg + ffprobe) into the plugin cache (~/.dsh-file-convert/bin), verifies the pinned sha256, and proves the binaries run before reporting success. Served from the npmmirror binary CDN with the GitHub release as a byte-identical fallback. System installs keep priority over the cache. Ask the user for consent first — it is a sizable download.

install_ocr_dependencies

Downloads the tesseract.js language data (about 10-30 MB per language, chi_sim+eng by default) into the plugin cache, so ocr: true works without a local Tesseract. Skips when a local Tesseract CLI is installed or the data is already cached. Ask the user for consent first — conversions never download language data implicitly.

list_conversions

All 26 conversions with their live availability on this machine — unavailable rows name the missing tool and how to install it. Images, PDF and data rows are usable out of the box; media, office and PDF-compression rows depend on the optional tools (media can even be set up by the agent via install_media_dependencies).

Plugin config

Limit coverage: maxInputMb applies to convert, batch, inspect and optimize alike; maxPdfPages applies to PDF rasterization and text extraction (both implicit full-document runs and explicit pages selections); maxOutputPixels applies to PDF rasterization, OCR rendering and SVG rasterization; timeoutMs truly cancels every conversion (the underlying work stops, it is not merely abandoned). | batchMaxFiles | 500 | Max files examined per batch_convert run; beyond it the summary reports what was skipped instead of silently capping | | outputRoots | [] | When non-empty, explicit output paths must resolve inside one of these directories (recommended for shared deployments; the default next-to-input output is always exempt) | | ffmpegPath / ffprobePath | - | Explicit binary paths when ffmpeg is not on PATH (common on Windows) | | sofficePath / ghostscriptPath / pythonPath / tesseractPath | - | Explicit paths for the optional tools, overriding auto-detection |

Architecture

                         DSH
                          │
                    dsh-file-convert
           ┌──────────────┴──────────────┐
     src/index.ts                   src/core/            ← the whole engine,
     (thin DSH glue:                (no DSH imports)       testable standalone
      name/inject/apply,                 │
      Config schema,                ConversionRouter
      7 tool registrations)              │
                       ┌─────────────────┼─────────────────┐
                       ↓                 ↓                 ↓
                 ImageConverter     PdfConverter      DataConverter
                    sharp          pdfjs-dist         js-yaml
                 (libvips npm)   @napi-rs/canvas    csv-parse / stringify
                                                     MediaConverter        OfficeConverter
                                                        ffmpeg (detected)      LibreOffice (detected)
                                                     PdfToDocxConverter    optimize_file/pdf
                                                     python + pdf2docx         Ghostscript (detected)

• Declarative matrix: every conversion is a data row ({ from, to }) on its converter. Routing, list_conversions and dependency checks are all derived from it.
• Detection: content first - binary magic (file-type), SVG sniffing, and JSON parsing (plus a YAML document-marker guess for extension-less files) - with the extension as fallback. Conflicts resolve in favor of the content, with a warning.
• Core is DSH-agnostic: src/core never imports Cordis/DSH, so the engine can be unit-tested, wrapped in a CLI, or served over MCP later. If the DSH developer-preview API shifts, only the glue layer changes.
• Dependencies: external binaries (FFmpeg, LibreOffice, Poppler) are detected, never auto-installed — list_conversions reports them and prints per-platform install hints. The interface is already in place (BinaryDependency).

Development

npm install
npm run build     # tsc -> lib/
npm test          # vitest, 77 tests (plus environment-gated suites)
npm run smoke     # end-to-end against lib/

Local development pulls the dsh-tools peer closure into devDependencies so typecheck and vitest can load the 0.1.5 tool registry. End users of the published plugin do not install these — the host profile provides them.

Add a conversion = add one capability row + implement it in a converter. Add a backend = implement the Converter interface and register it in createRouter().

Fidelity & safety expectations

• Lossy by nature: PDF→DOCX (experimental), OCR and office→PDF are reconstructions — expect layout and recognition differences. inspect_file's likelyScanned flag tells you when OCR is the right tool, and results carry warnings.
• Cached ffmpeg builds: the download convenience installs pinned sha256-verified FFmpeg 6.1.1 static builds. For untrusted media, a current system FFmpeg takes priority — prefer it in security-sensitive setups.
• Not a sandbox: outputRoots resolves symlinks and resource limits (maxInputMb, maxPdfPages, maxOutputPixels, batchMaxFiles) cap runaway jobs, but the default next-to-input output is intentionally exempt from roots, and an agent that may write files can always write somewhere. For hostile multi-tenant use, add OS-level isolation on top.

Compatibility

DSH is a developer preview and its APIs will move - the plugin keeps all DSH imports inside a thin glue layer so adapting stays cheap.

Roadmap

• V0.2 — Media (FFmpeg) shipped: MP4→GIF/MP3, WAV→MP3, MOV→MP4, plus optimize_file with target-size two-pass encoding.
• V0.3 — Office + PDF tooling shipped: DOCX/PPTX/XLSX→PDF via LibreOffice, experimental PDF→DOCX via python pdf2docx, PDF compression via Ghostscript; on-demand dependency downloads with an automatic CN mirror.
• V0.4 — OCR (Tesseract) shipped: PDF→TXT supports ocr: true (optional ocr_lang), local Tesseract CLI first with the bundled tesseract.js as fallback, language data fetched explicitly via install_ocr_dependencies.
• Later: OCR → DOCX for scanned PDFs, conversion chains (PPTX→PDF→PNG), video downscaling in optimize_file, resize/rotate image options.

License

MIT. dsh-file-convert distributes no external binaries; runtime libraries (sharp, pdfjs-dist, @napi-rs/canvas, js-yaml, csv) are installed from npm under their own licenses.