The pending counter was decremented when the job's guard dropped at the
end of the loop iteration, after the reply was sent, so a waiting caller
(CLI / MCP mask.add) could see the segmenter still busy right after its
answer arrived. Under a loaded test run that made
tests_segment::waiting_requests_with_a_damaged_model_are_errors fail on
assert!(!busy()). The guard is now dropped just before each reply.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01912WaK6Rmew3wxZuPyX7E8
Options::token_env (default none) replaces the hard-coded LIGHTCRAFT_SAM3_TOKEN, so a download of one model can
never send another model's token to its host. SAM 3 names its variable through lightcraft_segment::fetch::options().
The decision (non-empty, https, the host the download began at) is a small function with its own test.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
The downloader in lightcraft-segment (mirrors, resume, pinned SHA-256, pure-Rust
HTTPS) was already generic apart from four SAM 3 constants. Move it to
crates/fetch (L0, native only) so other model features can use it without
depending on the SAM 3 inference code. lightcraft-segment keeps SAM3_FILES,
DEFAULT_MIRRORS, MIRRORS_ENV and wraps mirrors(); no behaviour change. The
downloader's 13 tests moved with it.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Engine (crates/engine/src/segment/):
- One worker thread owns the model and the encoded photo; the session
sends jobs (with the render job for the model input) and gets results
over channels, never locking what the model holds. In the app
(Segmenter::background) clicks, descriptions, prepares and detail
passes return at once and Session::segment_poll applies results (one
undo step per settled selection, pending clicks shown on the photo);
the CLI/MCP wait for them. Newer requests for the same selection
supersede queued ones.
- Every job runs under catch_unwind: a candle panic becomes an error and
the model is reloaded next time; busy counters are reset by drop
guards; a dead worker is restarted. The model unloads after 10 min idle.
- segment.model.status / .download {acknowledged: true} / .cancel: the
download runs on its own thread; status via atomics (try_lock only).
Without the model every AI request fails at once with "The SAM 3 model
is not installed…"; renders/exports never need it; `seg` params make
AI masks from stored segmentations without it.
- Hostile documents: at most 4 detail patches per component (capped on
deserialize and in the renderer), at most 64 Object clicks.
UI: Object / Describe without the model open "Download the SAM 3
Model?" (size, folder, SAM License link; Not Now / Download, progress,
cancel, Try Again with the reason, Continue once installed); progress in
the Masking panel when the dialog is closed. Reverted the PR's unrelated
default change (mask overlay off + hover-red) to main's behaviour.
tools/install-sam3.*: --fail so error pages never land in files, 416
restarts instead of looping, the weights are verified before they are
moved into place (a bad file is deleted, never resumed from).
Docs: docs/ai-masks.md (in-app download, mirrors, SAM License summary,
no weights in the repo), NOTICE, parity LR-MASK-OBJECTS, What's New,
ROADMAP.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Brandon Thomas