Lets the model OCR a screenshot, scanned receipt, whiteboard photo,
or image-only PDF the user drops into the workspace, without
bouncing through `exec_shell` (which would mean an approval prompt
plus the model having to remember tesseract's CLI surface). The
tool spawns `tesseract <image> -` and returns the recognised text
inline — no file is written. Capability is ReadOnly + parallel
since OCR is a side-effect-free read.
Registration is gated on `crate::dependencies::resolve_tesseract()`
via the new `ToolRegistryBuilder::with_image_ocr_tools()` builder,
hooked into `with_agent_tools` alongside `pandoc_convert`. When
tesseract is missing the tool isn't advertised — same
probe-then-decide pattern v0.8.31 introduced for Python. The
execute path also late-resolves so a concurrent uninstall surfaces
the install-tesseract hint rather than the raw spawn failure.
`deepseek doctor`'s "Tool Dependencies" section reports tesseract
status next to pandoc / node / python with platform-aware install
hints. For non-default language packs or PSM modes the user can
still drop into `exec_shell` with the full tesseract CLI surface.
Tests check the metadata (ReadOnly + parallel, not WritesFiles),
the missing-path rejection, and the happy-path OCR round-trip
against `crates/tui/tests/fixtures/ocr_hello.png` — a 2 KB
300×100 grayscale PNG generated with ImageMagick rendering
"HELLO OCR" in Helvetica. The happy-path test skips silently on
hosts without tesseract (matching the catalog-build behaviour) and
on hosts where the fixture isn't checked out (sparse / shallow
clones).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Hunter Bown
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