tactual

Tactual

Screen-reader navigation cost analyzer. Measures how hard it is for assistive-technology users to discover, reach, and operate interactive targets on the web.

What it does

Existing accessibility tools check conformance — is the ARIA correct? Is the contrast ratio sufficient?

Tactual measures navigation cost — how many actions does it take a screen-reader user to reach the checkout button? What happens if they overshoot? Can they even discover it exists?

It works by capturing Playwright accessibility snapshots, building a navigation graph, and scoring each target under an assistive-technology profile.

Install

npm install tactual playwright

Playwright is an optional peer dependency — required for the CLI and page analysis, not needed if you only use the library API with pre-captured states.

Quick start

CLI

# Analyze a URL (default profile: generic-mobile-web-sr-v0)
tactual analyze-url https://example.com

# Analyze with a specific AT profile
tactual analyze-url https://example.com --profile voiceover-ios-v0

# Explore hidden UI (menus, tabs, dialogs, disclosures)
tactual analyze-url https://example.com --explore

# Output as JSON, Markdown, or SARIF
tactual analyze-url https://example.com --format json --output report.json
tactual analyze-url https://example.com --format sarif --output report.sarif

# Compare two analysis runs
tactual diff baseline.json candidate.json

# List available AT profiles
tactual profiles

# Run benchmark suite
tactual benchmark

# Initialize a tactual.json config file
tactual init

Library API

import { analyze, getProfile } from "tactual";
import { captureState } from "tactual/playwright";
import { chromium } from "playwright";

const browser = await chromium.launch();
const page = await browser.newPage();
await page.goto("https://example.com");

const state = await captureState(page);
await browser.close();

const profile = getProfile("generic-mobile-web-sr-v0");
const result = analyze([state], profile);

for (const finding of result.findings) {
  console.log(finding.targetId, finding.scores.overall, finding.severity);
}

MCP Server

Tactual includes an MCP server for AI agent consumption:

# Start the MCP server (stdio transport)
tactual-mcp

MCP tools available:

Tool	Description
analyze_url	Analyze a web page for SR navigation cost. Default format is sarif. Supports waitForSelector, waitTime, minSeverity, focus, excludeSelector, exclude, maxFindings, summaryOnly, timeout params. Findings include Playwright locator selectors. Pass probe: true for deep investigation with keyboard probes (focus, activation, Escape recovery).
trace_path	Trace the step-by-step navigation path to a specific target. Shows each action, cost, and modeled screen-reader announcement. Accepts target ID or glob pattern (e.g., *search*).
list_profiles	List available AT profiles
diff_results	Compare two analysis results. Shows penalties resolved/added, severity changes, and status per target.
suggest_remediations	Ranked fix suggestions by impact. Redundant for SARIF output (fixes are inline).
save_auth	Authenticate with a web app and save session state. Pass the output file path as storageState to other tools for analyzing authenticated content.
analyze_pages	Analyze multiple pages in one call with site-level aggregation. Returns ~200 bytes per page. Use for site triage before diving into individual pages.

Configure in your MCP client:

{
  "mcpServers": {
    "tactual": {
      "command": "tactual-mcp"
    }
  }
}

GitHub Actions

Add to your CI pipeline:

- name: Install Tactual
  run: npm install tactual playwright

- name: Install browsers
  run: npx playwright install chromium --with-deps

- name: Run accessibility analysis
  run: npx tactual analyze-url https://your-app.com --format sarif --output results.sarif --threshold 70

- name: Upload SARIF
  uses: github/codeql-action/upload-sarif@v3
  with:
    sarif_file: results.sarif

Or use the reusable workflow:

jobs:
  a11y:
    uses: tactual-dev/tactual/.github/workflows/a11y-analysis.yml@master
    with:
      url: https://your-app.com
      explore: true
      fail-below: 70

Configuration

CLI flags

Options:
  -p, --profile <id>              AT profile (default: generic-mobile-web-sr-v0)
  -f, --format <format>           json | markdown | console | sarif (default: console)
  -o, --output <path>             Write to file instead of stdout
  -d, --device <name>             Playwright device emulation
  -e, --explore                   Explore hidden branches
  --explore-depth <n>             Max exploration depth (default: 3)
  --explore-budget <n>            Max exploration actions (default: 50)
  --explore-max-targets <n>       Max accumulated targets before stopping (default: 2000)
  --exclude <patterns...>         Exclude targets by name/role glob
  --exclude-selector <css...>     Exclude elements by CSS selector
  --focus <landmarks...>          Only analyze within these landmarks
  --suppress <codes...>           Suppress diagnostic codes
  --top <n>                       Show only worst N findings
  --min-severity <level>          Minimum severity to report
  --threshold <n>                 Exit non-zero if avg score < N
  --config <path>                 Path to tactual.json
  --no-headless                   Headed browser (for bot-blocked sites)
  --timeout <ms>                  Page load timeout (default: 30000)
  -q, --quiet                     Suppress info diagnostics

tactual.json

Create with tactual init or manually:

{
  "profile": "voiceover-ios-v0",
  "exclude": ["easter*", "admin*", "debug*"],
  "excludeSelectors": ["#easter-egg", ".admin-only", ".third-party-widget"],
  "focus": ["main"],
  "suppress": ["possible-cookie-wall"],
  "threshold": 70,
  "priority": {
    "checkout*": "critical",
    "footer*": "low",
    "analytics*": "ignore"
  }
}

Config is auto-detected from the working directory (tactual.json or .tactualrc.json). CLI flags merge with and override config settings.

AT Profiles

Profile	Platform	Description
generic-mobile-web-sr-v0	Mobile	Normalized mobile SR primitives (default)
voiceover-ios-v0	Mobile	VoiceOver on iOS Safari — rotor-based navigation
talkback-android-v0	Mobile	TalkBack on Android Chrome — reading controls
nvda-desktop-v0	Desktop	NVDA on Windows — browse mode quick keys
jaws-desktop-v0	Desktop	JAWS on Windows — virtual cursor with auto forms mode

Profiles define the cost of each navigation action, score dimension weights, costSensitivity (scales the reachability decay curve), and context-dependent modifiers. See src/profiles/ for implementation details.

Scoring

Each target receives a 5-dimension score vector:

Dimension	What it measures
Discoverability	Can the user tell the target exists?
Reachability	What is the navigation cost to get there?
Operability	Does the control behave predictably?
Recovery	How hard is it to recover from overshooting?
Interop Risk	How likely is AT/browser support variance? (penalty)

Dimension weights vary by profile:

Profile	D	R	O	Rec	costSensitivity
generic-mobile-web-sr-v0	0.30	0.40	0.20	0.10	1.0
voiceover-ios-v0	0.30	0.35	0.20	0.15	1.1
talkback-android-v0	0.25	0.45	0.20	0.10	1.3
nvda-desktop-v0	0.35	0.25	0.30	0.10	0.7
jaws-desktop-v0	0.30	0.25	0.35	0.10	0.6

Composite: Weighted geometric mean: overall = exp(sum(w_i * ln(score_i)) / sum(w_i)) - interopRisk. Each dimension is floored at 1 before the log to avoid log(0). This means a zero in any dimension drags the overall score down sharply -- you cannot operate what you cannot reach.

Severity bands:

Score	Band	Meaning
90-100	Strong	Low concern
75-89	Acceptable	Improvable
60-74	Moderate	Should be triaged
40-59	High	Likely meaningful friction
0-39	Severe	Likely blocking

Diagnostics

Tactual detects and reports when analysis may be unreliable:

Code	Level	Meaning
blocked-by-bot-protection	error	Cloudflare/bot challenge detected
empty-page	error	No targets found at all
possibly-degraded-content	warning	Suspiciously few targets for an http page
sparse-content	warning	Only 1-4 targets found
possible-login-wall	warning	Auth-gated content (detects /login, /signin, /auth path redirects)
possible-cookie-wall	info	Cookie consent may obscure content
redirect-detected	warning	Landed on different domain
no-headings	warning	No heading elements found
no-landmarks	warning	No landmark regions found

Exploration

The --explore flag activates bounded branch exploration:

• Opens menus, tabs, disclosures, accordions, and dialogs
• Captures new accessibility states from hidden UI
• Marks discovered targets as requiresBranchOpen
• Respects depth, action count, target count, and novelty budgets
• Safe-action policy blocks destructive interactions

Exploration is useful for pages with significant hidden UI (e.g., dropdown menus, tabbed interfaces, modal dialogs).

Exploration candidates are sorted by a stable key (role + name) before iterating, so the same page content produces the same exploration order across runs.

Exploration budgets

Budget	CLI flag	Default	Purpose
Depth	--explore-depth	3	Max recursion depth
Actions	--explore-budget	50	Total click budget across all branches
Targets	--explore-max-targets	2000	Stop if accumulated targets exceed this
Time	(library only)	120s	Global wall-clock timeout

SPA framework detection

Tactual detects when SPA content has rendered before capturing the accessibility tree. Detected frameworks: React, Next.js, Vue, Nuxt, Angular, Svelte, and SvelteKit. Generic HTML5 content signals (landmarks, headings, navigation, links) are also checked. For SPAs not covered by auto-detection, use --wait-for-selector (CLI) or waitForSelector (MCP/API) to specify a CSS selector that indicates your app has hydrated.

After initial framework detection, Tactual uses convergence-based polling — repeatedly snapshotting the accessibility tree until the target count stabilizes — which works regardless of framework.

Interop Risk

Tactual includes a static snapshot of ARIA role/attribute support data derived from a11ysupport.io and the ARIA-AT project. Roles with known cross-AT/browser support gaps receive an interop risk penalty.

Role	Risk	Note
button, link, heading	0	Well-supported
dialog	5	Focus management varies
combobox	8	Most interop-problematic pattern
tree	10	Poorly supported outside JAWS
application	15	Dangerous if misused

Output Format Recommendations

Format	Typical size	Best for
console	~8KB	Human review in terminal
markdown	~11KB	PRs and issue comments
json	~18KB	Programmatic consumption
sarif	~43KB	GitHub Code Scanning / CI

All non-SARIF formats emit summarized output: stats, grouped issues, and worst findings (capped at 15). SARIF caps at 25 results. When output is truncated, a note appears at the top.

For MCP usage, sarif is the default and recommended format. Use summaryOnly: true for a minimal health check (~835 bytes: stats, severity counts, top 3 issues).

Calibration

Tactual includes a calibration framework (src/calibration/, exported as tactual/calibration) for tuning scoring parameters against ground-truth datasets. See docs/CALIBRATION.md for details.

Development

npm install                    # Install dependencies
npm run build                  # Build with tsup
npm run test                   # Run unit + integration tests
npm run test:benchmark         # Run benchmark suite
npm run typecheck              # TypeScript type checking
npm run lint                   # ESLint

Security

Browser sandboxing

Tactual always runs Playwright with default Chromium sandboxing enabled. It never disables web security or modifies the browser's security model. All page interactions happen within the standard Chromium process sandbox.

Safe-action policy

When exploration is enabled (--explore), Tactual classifies interactive elements into three tiers before activating them:

Tier	Action	Examples
Safe	Activated	Tabs, menu items, disclosures, accordions, same-page anchors
Caution	Activated with care	External links, ambiguous buttons, submit buttons
Unsafe	Skipped	Delete, sign out, purchase, deploy, unsubscribe

This is a keyword-based heuristic — it cannot detect semantic deception (e.g., a "Save" button that actually deletes data) or inspect server-side behavior. For production use, always run exploration against trusted or sandboxed environments.

URL validation

All URLs are validated before navigation. Private/internal IP ranges and non-HTTP(S) schemes are rejected by default.

License

Apache-2.0