MCP Registry: io.github.Tavrin/saccade

saccade

saccade is a visual and performance evidence tool for humans, CI and AI agents. It measures perceptual differences, locates them in measured regions (with optional advisory observations), and checks them against the thresholds and policies you declare. It writes offline HTML reports and versioned JSON. Performance conclusions require comparable captures, timing provenance and repeat evidence. Only a human can approve a baseline.

Quickstart

saccade demo --out saccade-demo
saccade view saccade-demo

The demo exits 1 on purpose: it contains changed and missing captures. Open saccade-demo/report/index.html to see the result. The quickstart walkthrough has copyable examples for comparison, exact identity, configuration, evidence export and local review. Not sure which command fits? Use the task map and the five tested guides: visual CI, controlled rendering, document export, media intake and delivery tuning. saccade doctor shows what your install can run.

Use cases

Visual verification for coding agents

The local MCP server reads registered capture roots and writes reports under a separate output root. Its tools cannot approve baselines. Agents can inspect bounded results and follow recorded next actions.

saccade mcp --root captures --out-root agent-reports
saccade compare captures/before captures/after --out agent-reports/change --json

See the agent guide and MCP and plugin setup.

CI visual regression

The local Playwright package provides toMatchSaccade and capture stabilization. A sweep groups page pairs and records capture failures as failures.

node integrations/playwright/sweep.cjs sweep.json captures capture-options.json
saccade sweep compare sweep.json --captures captures/captures.json --out sweep-report --json

See the Playwright matcher, sweep and CI integration. Sweep needs the optional products feature.

Render and engine evidence

Declared spatial policies distinguish texture_noise_only from systematic_shift. Required-effect checks can fail on an empty footprint; capture layers restrict measurement scope and fixed-camera sequences measure temporal stability. Supply the policies and capture provenance with your inputs.

saccade compare before after --config render-evidence.toml --out render-report --json
saccade experiment sequence before-frames after-frames --fixed-camera --out temporal-report --json

See rendering evidence and engine capture ingestion, temporal settling and one-flag masks.

Image delivery tuning

Audit served formats and search declared encodings for a perceptual target. Local and URL-template adapters record bytes and content types and do not modify originals.

saccade imgtune audit --urls images.txt --accept 'image/avif,image/webp,image/*' --out audit.json --json
saccade imgtune search tuning.json --out tuning-report.json --json

See image tuning. Enable products, plus imgtune-avif for AVIF.

Media analysis records

A media record keeps status and provenance for metadata, quality, fingerprints and optional model sections. Disabled or failed sections are recorded as such. The Python package and local HTTP API use the same analysis path.

saccade analyze-media image.jpg --profile cpu-lite --output-size 1200x800 --json
saccade keyframes video.mp4 --out frames --json

See media analysis, Python and HTTP API. Install with pip install saccade-vision (Python 3.10+); the import stays import saccade.

Single-image provenance and integrity

Inspect C2PA credentials, metadata and compression-history indicators without a baseline. Heuristics have stated limits and do not establish a real/fake verdict. GPS disclosure is opt-in; C2PA validation needs credentials.

saccade inspect-image received.jpg --output-size 1600x900 --out inspection --json
saccade inspect-image received.png --hash-index hashes/saccade-hash.v1.json --out indexed-inspection --json

See single-image inspection.

General comparison

Pick registration, hashes, embedding similarity/search, OCR text differences, no-reference quality or document rasterization to fit the question. Model workflows require supplied pinned artifacts and the relevant features.

saccade compare before.png after.png --align similarity --out aligned-report --json
saccade text before.png after.png --out text-report --json
saccade assess image.jpg --out quality-report --json

See choosing a comparison, registration, hashing, embeddings and search, OCR, quality and documents.

Performance evidence

Compare supplied timing sidecars using paired statistics and uncertainty intervals, or locate changes in a sequence. Saccade does not run the benchmark; missing or rejected provenance cannot qualify a speedup.

saccade compare before after --out perf-report --json
saccade history onset --store history --json

See paired statistics, change points, identity/performance, timing verdicts, ablation tables and report linking. The performance sidecar kit has fixtures and recipes for producers. Label images can be scored with mask metrics, boxes exchanged as COCO or YOLO (box interchange), and extracted video frames described by a frame map.

Install

Install with Rust 1.89 or newer:

cargo install saccade --version 0.3.0 --locked
saccade doctor --json

To build this checkout, use cargo install --locked --path crates/saccade. Release archives include checksums, licences and third-party notices. See release instructions.

Video extraction invokes external ffmpeg and ffprobe; neither is bundled. See model/runtime provisioning and AVIF prerequisites. Default comparisons need no provider account or GPU. Add optional features with cargo install ... --features products,ocr, for example.

Crates

With the prechecks feature, a11y auto finds text and UI regions in an image and checks them, offline:

saccade a11y auto screenshot.png --out accessibility-report

Metrics and algorithms

Each qualification covers only the recorded contract and evidence. A passing score does not prove correctness or that a difference is invisible.

AI layer

AI observations are advisory. They cannot approve baselines, create exclusions, override deterministic failures, establish equality or qualify timing. Providers are opt-in, with source-root egress authorization, dedicated credential files and call/spend caps; image text and provider output are data, never instructions.

The release qualification attempt with a $15 cap stopped at the prerequisite check, before any provider request or spend. No frozen corpus with an observed immutable Gemini revision or exact-source heavy receipt was supplied. Explain, mask audit, visible-condition checks, blind orders, Jev support, deterministic cascade routing and optional Jev evidence routing all remain unqualified. Assist commands still require --experimental; Jev routing stays off by default. See assist workflows, qualification policy and the release guide.

Known limitations

• OCR can misread œ in large serif text and omit dashes with some sans fonts; omitted characters and missing spaces before € remain errors.
• Retrieval scores lack qualified calibration. Model/runtime smokes establish execution, not production accuracy or export parity.
• GI occupancy uses supplied masks/layers as a proxy; it does not prove physical illumination, causality or correct rendering.
• LPIPS, DISTS and MUSIQ have no shipped checkpoints (quality-score needs your reviewed export); TrustMark Q decoding requires explicitly provisioned local models.
• Captures define the evidence scope. Equal images do not establish application correctness, and perceptual passes do not establish native sample identity.
• Performance conclusions need matched workload, clocks, warmup and repeat noise. Missing checks remain unknown; human approval records do not authenticate an operator.

Documentation and integrations

• Documentation, CLI reference and JSON contracts/schemas.
• MCP server and plugins, agent guide, Python package (PyPI: saccade-vision), HTTP API and CI.
• CHANGELOG, release guide and contributing.

9 reproducible cases with commands, expected exits and measured output. Pages gallery.

License

MIT OR Apache-2.0, at your option. FLIP uses the BSD-3-Clause flip-rs port. See third-party notices; release archives also include generated dependency notices.

MCP Registry ownership: mcp-name: io.github.Tavrin/saccade

Saccade originated in the Moss engine’s visual testing tools.

Verify final QR/barcode payloads independently of visual comparison with the optional optical-code feature; PDF/SVG pages also require documents.

Rust callers can use saccade-core workflows for command-level comparison, approval, history, manifests, batch and review without CLI dispatch.