dsh-ocr-free

dsh plugin --profile web add dsh-ocr-free

dsh-ocr-free

Local OCR for DeepSeek Harness: read the text out of

a screenshot, photo or scan without the network and without an API key.

On macOS the engine is Apple Vision, compiled from a 130-line Swift file on first use and cached — so

there is nothing to install either. Elsewhere an installed tesseract is used instead, and if neither

engine is available the tool fails and says why — it never returns an empty reading.

[ dsh-ocr-free ] engine=vision recognizer=accurate lines=7 time=2.0s
=== text ===
Договор управления Nº 14/2026
Чл. 50, ал. 1 - Общото сьбрание създава етажна собственост
=================================================================

Why this exists

A model that declares no image input cannot be handed a picture: DSH refuses the paste before anything

is written to disk (Model "…" does not support image input, MODEL_DOES_NOT_SUPPORT_IMAGES). There

are two ways to answer that. One is to tell the host the model accepts images after all; the other is

to hand the model text, which is all it was going to get out of the picture anyway.

This plugin does the second, and only the second. It adds two tools and changes nothing else — no

capability claims, no prompt rewriting, no host row overrides. A plugin that lies about

inputModalities changes how every request in the session is assembled; a plugin that adds a tool

changes the tool list.

The first way is worth knowing too, because it is one line and it works: declare the modality on the

model entry in the profile (input: [text, image] for llm-pi-ai, inputModalities for the DeepSeek

provider). Measured on 2026-10-01 — with that single line, a screenshot dropped into the composer on a

hand-written b.ai route was accepted, and the model read it.

Install

# from a package
dsh plugin --profile web add dsh-ocr-free

# or from a checkout (edits take effect on the next host start)
dsh plugin --profile web add link:~/git/dsh-ocr-free

There is no exemption to grant and no engine to install. Requires DSH ^0.2.0-rc.2 (the only version

this is verified against) and Node 22+.

platform · engine · what you need

macOS · Apple Vision (default) · Swift command-line tools: xcode-select --install

Linux · tesseract · tesseract-ocr from your distribution, plus language data

Windows · tesseract · untested — the engine lookup does not resolve tesseract.exe (Node does not apply PATHEXT when spawning), so it will report the engine as missing even when it is installed

So the zero-install claim is a macOS claim. On Linux this is a thinner thing: a wrapper around

tesseract that adds the confidence section, the live settings card and errors that name their cause.

Tools

ocr_image

argument · meaning

path (required) · image file: PNG, JPEG, HEIC, TIFF, GIF, BMP

langs · preferred languages (Vision ru-RU/en-US; tesseract rus/bul/eng). Omit for the configured value; [] lets the engine detect the script itself

engine · auto (default), vision or tesseract — per call

fast · the fast recogniser (~3× quicker, Latin-only — see below)

The result is the recognised text, plus a header naming the engine and the timing, plus a separate

list of lines the engine itself scored below lowConfidence:

=== uncertain (confidence < 0.7) ===
[0.50] Чл. 50, ал. 1 - Общото сьбрание създава етажна собственост

That section is the point of the tool. OCR output looks equally confident whether it is right or

wrong; the engine's own score is the only thing that separates a reading from a guess, and on the

samples measured here the one mis-recognised letter sat on the one line scored 0.50.

ocr_status

Reports which engine this machine can use and why, without reading an image. It does not build the

engine (a status call should not have that side effect) — it answers whether the build is already

there, whether a compiler exists, and whether tesseract is installed.

Configuration

The plugin row is ocr-free; the settings card edits these fields live (no restart):

field · default · meaning

engine · auto · auto prefers Vision, falls back to tesseract; a pinned engine reports its own failure instead of silently switching

langs · [] · [] asks for nothing in particular — see the language note below

fast · false · the fast recogniser; Latin-only

detectLanguage · false · let Vision guess the language too; costs 0.2–0.9 s per image

maxChars · 40000 · truncate the rendered text (0 = no cap); truncation is always announced

lowConfidence · 0.7 · below this, lines are listed separately (0 = no section)

timeoutMs · 120000 · per-image engine budget

dir · "" · engine build directory; "" means ~/.dsh-ocr-free

includeEngineLine · true · the header with engine, timing and warnings

Measured behaviour

Taken on macOS 15.4.1 (build 24E263), Apple silicon, against a 1000×200 crop of Cyrillic text and an

824×907 UI screenshot:

case · time · notes

1000×200, accurate · 1.6 s · 7/7 lines correct

1000×200, accurate + language detection · 1.8 s · identical output

1000×200, fast · 0.5 s · Latin lookalikes: Договор управления → oroBOP ynpaBneHMA

824×907 screenshot, accurate · 3.0 s · 38 lines

824×907 screenshot, accurate + detection · 3.9 s · identical output

Three findings worth carrying:

• The fast recogniser is Latin-only. Asked for Cyrillic it does not fail — it returns Latin

homoglyphs with high confidence. This holds for every requested language, so it is a property of the

level, not of the hint; fast stays off by default and the tool repeats the caveat whenever it is on.

• Language hints do not matter for Cyrillic on this build. Vision's requestable language li

…(truncated)