JustTools

Fast, opinionated, cross-platform just* commands in one compiled Rust executable. There is no Node, Bun, or PowerShell runtime layer. just install creates native aliases, so the same binary runs as justjson, justpdf, justvideo, and every other command.

JustTools is built by the team behind JustGains. Try JustGains for a fast, focused way to build workouts, track progress, and get stronger.

Install

Build from source, then let the binary install itself:

cargo build --locked --release -p justtools
.\target\release\just.exe install

cargo build --locked --release -p justtools
./target/release/just install

The default destination is C:\cmd\bin when that directory already exists on Windows, otherwise the per-user application directory on Windows and ~/.local/bin on macOS/Linux. Override it with --bin-dir or JUSTTOOLS_BIN. Existing managed JustTools files are moved to a timestamped recovery directory before the staged native install commits. A failed upgrade rolls the prior installation back.

If the install directory is not on PATH, the just browser offers Add To Path. The direct commands are just add-to-path and just install. Open a new terminal after changing PATH.

Commands and defaults

Command	Opinionated default
just	Browse or directly dispatch every command; offer Add To Path when needed
justaudio	AAC-LC M4A, 160 kb/s, 48 kHz; keep the source
justavif	AV1 still image, quality 60, speed 6; install only when smaller
justcrop	Trim transparent borders to nonzero-alpha bounds; preserve format and source
justjpg	Quality 85 progressive 4:2:0 JPEG, optimized Huffman tables, white alpha background
justjson	Pretty-print in place with two spaces and a final newline
justmp3	LAME VBR quality 2, 48 kHz; keep the source
justpdf	Show info for one PDF or merge several into merged.pdf
justpng	pngquant quality 65-90, speed 3; replace only when smaller
justport	Show the owner of exact local ports; guarded same-user kill is optional
justqr	1024 px, error-Q, four-module margin, black-on-white qr.png
justresize	Fit still images within 1920x1920, never upscale, preserve format and source
justrmbg / rmbg	Local BRIA RMBG-2.0 removal to <name>-nobg.png
justsvg	Conservative multipass SVGOMG-style optimization, precision 3
justvideo	720p H.264 MP4, CRF 28, medium preset, AAC 128 kb/s
justwav	Stereo 16-bit PCM WAV at 48 kHz; keep the source
justwebp	Quality 82, method 5 WebP; replace only when smaller
justzip	Smallest-compression ZIP from Git's exact tracked/unignored file set

Run just, just --help, or just help qr. Short dispatch stays quick:

just qr "https://example.com"
just crop transparent-logo.png
just jpg photo.png
just resize photo.jpg --width 1200
just json package.json
just pdf report-a.pdf report-b.pdf
just mp3 interview.mov
just port 4321
just rmbg portrait.jpg

Consistent file handling

• File tools accept files, folders, Unicode paths, and -- before unusual path names. Folder scans are direct unless --recursive is selected.
• Batch tools consistently expose --output, --yes, --dry-run, and --help; encoders also expose --jobs.
• Inputs are normalized and deduplicated. Output collisions and input/output overlap are rejected before processing.
• Outputs are written beside their destination and atomically installed. Existing modes are preserved for in-place document edits.
• Destructive folder operations ask once. Explicit-file operations remain low-friction, while --yes makes automation intentional.
• Audio tools keep sources unless --replace is explicit. WebP and AVIF remove a beside-source original only after a smaller replacement is complete.
• APNG, animated WebP/AVIF, multi-page TIFF, and AVIF transparency are rejected where a still-image conversion would silently discard content.
• Crop applies EXIF orientation, trims to alpha values above the selected threshold, clamps optional padding to the original canvas, and reduces fully transparent canvases to a valid 1x1 transparent image.
• JPG applies EXIF orientation, composites transparency onto white by default, writes progressive 4:2:0 output with optimized Huffman tables, and strips metadata. Quality 90+ switches to full 4:4:4 chroma. Use --background, --quality, or --baseline when needed.
• Resize applies EXIF orientation, uses Lanczos3, strips metadata, and preserves aspect ratio unless exact center-cropping is explicitly selected.
• PDF inputs are never deleted. Page ranges are one-based, such as 1-3,5,last.
• ZIP paths, symlinks, output self-inclusion, Git submodules, and ZIP64 files are handled explicitly; unsafe links that escape the archive root fail closed.

justjson and justsvg treat piped input as document content. justqr treats piped input as text. Media, PDF, and RMBG commands accept paths; see each command's --help for its exact batch behavior.

justsvg uses OXVG, a Rust-native optimizer modeled on SVGO/SVGOMG. Its conservative preset preserves IDs, viewBox, titles, descriptions, XML namespaces, and accessibility attributes.

Third-party attribution for the native JPEG encoder ships in THIRD_PARTY_LICENSES.md and every release archive.

Dependencies: discover, explain, confirm

Pure-Rust crop, JPG, JSON, PDF, QR, resize, SVG, and port operations have no external runtime dependencies. Other commands resolve dependencies only when invoked:

Commands	Dependency	Confirmed acquisition
audio, AVIF, MP3, video, WAV	FFmpeg + ffprobe	WinGet, Homebrew, apt, dnf, or pacman
PNG	pngquant	package manager, or checksum-pinned official Windows archive
WebP	cwebp	WinGet or the platform WebP package
ZIP	Git	native package manager
RMBG	ONNX Runtime + BRIA model	checksum-pinned official runtime archive, then checksum-pinned S3 model archive

When something is missing, JustTools prints the exact source and command, then asks [y/N]. It runs the installer only after a real y/yes from an interactive terminal. Redirected input, CI, and other non-interactive runs never install or download anything; they return actionable instructions instead. Declining leaves the filesystem unchanged.

Dependency installation cannot be bypassed with --yes. That flag applies to the requested file operation or JustTools' own managed install, not third-party software. Override discovery without enabling installation by setting FFMPEG_BIN, FFPROBE_BIN, PNGQUANT_BIN, CWEBP_BIN, or GIT_BIN to a specific executable.

The Fedora ffmpeg-free package can omit libx264, libmp3lame, or libaom-av1. JustTools warns before installation and verifies the exact encoder needed by the current command before touching inputs.

RMBG runtime and model

justrmbg resolves ONNX Runtime before it offers the much larger model download. A missing portable CPU runtime is fetched from Microsoft's official release assets only after confirmation, with platform, size, and SHA-256 pinned for Windows, Linux, and macOS on x64 and ARM64. ORT_DYLIB_PATH can point to a provider-enabled runtime for DirectML, CUDA, or CoreML.

The BRIA RMBG-2.0 archive is hosted at https://m.justgains.com/tools/rmbg-2.0.zip, verified by SHA-256, selectively extracted, and installed atomically in the per-user cache. Use --model or RMBG_MODEL for an existing ONNX file. Custom mirrors require both RMBG_MODEL_ARCHIVE_SHA256 and RMBG_MODEL_SHA256 alongside RMBG_MODEL_URL.

Automatic mode tries the platform GPU providers and falls back to CPU, including an inference-time retry if a GPU provider initializes but fails. --cpu and --gpu make that choice explicit.

BRIA publishes the RMBG-2.0 weights for non-commercial use. Commercial use requires a separate agreement; review the BRIA model card and license before using the downloaded weights.

Agent skill

The repository includes an installable justtools Agent Skill at skills/justtools. The skills npm CLI discovers it directly from GitHub:

npx skills add JustGains/JustTools --skill justtools

Target specific agents or install globally when desired:

npx skills add JustGains/JustTools --skill justtools --agent codex --agent claude-code
npx skills add JustGains/JustTools --skill justtools --agent codex --global

Use npx skills add . --skill justtools from a local clone while developing the skill. Set DISABLE_TELEMETRY=1 if you do not want the installer's anonymous usage telemetry.

Development and releases

cargo fmt --all -- --check
cargo check --locked --workspace --all-targets
cargo test --locked --workspace --all-targets
cargo clippy --locked --workspace --all-targets -- -D warnings
cargo build --locked --release -p justtools

The test suite exercises every advertised command through the root binary, native alias installation and rollback, non-interactive dependency refusal, real JSON/PDF/QR/SVG/port behavior, Git-accurate ZIP creation, media safety, native crop/JPG/resize behavior, and offline RMBG acquisition logic. CI also checks the Rust 1.90 minimum and builds native release archives for Windows x64/ARM64, Linux x64/ARM64 on an Ubuntu 22.04 compatibility baseline, and macOS Intel/Apple Silicon. Unix artifacts are tarred so executable permissions survive artifact transport. Workflow actions use their current Node 24-based major releases.

Every push and pull request keeps its native archives on the Actions run. A version tag matching Cargo.toml, such as v2.2.0, additionally creates a GitHub Release and attaches all six archives. Re-running the release job safely replaces its existing assets.