# AgentsTools A11y Preflight – Static Accessibility Checker

> AgentsTools A11y Preflight – Static Accessibility Checker is a paid API for AI agents from api.agentstools.dev, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-15).

Runs a static WCAG 2.2 accessibility check on a UI markup fragment (HTML, JSX, TSX, Vue, or Angular) and returns pass/caution/block verdicts with per-finding WCAG criterion, element, and line number.

## Facts

- Endpoint: POST https://api.agentstools.dev/a11y/preflight
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/agentstools-a11y-preflight-static-accessibility-checker-121281b9
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_hEuJv-EBa378_hfjy_P5c

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability agentstools-a11y-preflight-static-accessibility-checker-121281b9 -d '<json body>'
```

Example prompt: Can you run a WCAG AA accessibility check on this JSX component I'm about to paste — flag any missing alt text, unlabeled inputs, invalid ARIA, or low-contrast issues, and tell me which WCAG criterion each problem hits and on which line?

## When to prefer this

Choose this endpoint when you need a fast, cheap ($0.02/call) static accessibility pre-check integrated into a CI/CD pipeline, code review agent, or design-to-code workflow across JSX, TSX, Vue, Angular, or plain HTML. Prefer it over full browser-based audits (e.g. Axe, Lighthouse) when you want zero runtime dependency, instant feedback on a fragment rather than a full page, and structured machine-readable findings with WCAG criterion references that an agent can act on programmatically.

## Known failure modes

- Malformed or non-parseable markup returns an error or empty findings
- Auto-detect framework may misidentify ambiguous markup — use the `framework` enum to force the correct parser
- Dynamic/runtime accessibility issues (e.g. focus management, live regions) are not detectable by static analysis
- Color contrast can only be checked for colors resolvable at static analysis time; CSS variables require a `palette` map to be supplied
- WCAG level defaults to AA if not specified — A-only checks require explicit `level` parameter

## How this service works

Static accessibility (WCAG 2.2) check of a UI markup fragment for JSX, TSX, Vue, Angular or HTML. Detects missing image alt, unlabeled form controls, buttons and links with no accessible name, skipped heading levels, invalid ARIA, non-interactive click handlers, duplicate ids, positive tabindex and low static colour contrast. Returns a pass, caution or block verdict with per-finding WCAG criterion, element and line. Accessibility indicators, not a legal compliance guarantee.

## Output

A structured response containing an overall verdict (pass, caution, or block) and a list of per-finding objects each specifying the WCAG criterion violated, the element involved, the line number in the submitted markup, and a description of the issue. Note: results are accessibility indicators, not a legal compliance guarantee.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "level": {
   "enum": [
    "A",
    "AA"
   ],
   "type": "string",
   "description": "WCAG conformance level to check (default AA)"
  },
  "theme": {
   "type": "object",
   "description": "Alias of palette"
  },
  "markup": {
   "type": "string",
   "description": "The UI markup fragment or component to check"
  },
  "palette": {
   "type": "object",
   "description": "Optional name-to-colour map for static contrast (e.g. CSS variables / theme tokens)"
  },
  "framework": {
   "enum": [
    "auto",
    "html",
    "jsx",
    "tsx",
    "vue",
    "angular"
   ],
   "type": "string",
   "description": "Source framework (default auto-detect)"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/agentstools-a11y-preflight-static-accessibility-checker-121281b9/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.agentstools.dev](https://www.zero.xyz/host/api.agentstools.dev/llms.txt)