# Accessibility Linting URL: /kida/docs/advanced/a11y-linting/ Section: advanced Description: Static accessibility checks for templates — img-alt, heading-order, html-lang, input-label --- > For a complete page index, fetch /kida/llms.txt. Kida can statically analyze parsed templates for common accessibility issues — missing alt text, skipped heading levels, missing `lang` attributes, and unlabeled form elements. Checks run against the template AST, so they catch issues in static markup without requiring a render pass. ```python from kida.analysis.a11y import check_a11y ``` ## Available Rules | Rule | Severity | What It Checks | |---|---|---| | `img-alt` | error | `` tags must have an `alt` attribute. Images with `role="presentation"` or `role="none"` are exempt. | | `heading-order` | warning | Heading levels must not skip (e.g., `

` directly followed by `

`). | | `html-lang` | warning | The `` tag must have a `lang` attribute. | | `input-label` | warning | ``, `` elements must have an associated `<label for="...">`, `aria-label`, `aria-labelledby`, or `title` attribute. Hidden inputs are exempt. | ## Usage ### Python API Run accessibility checks on any parsed template AST: ```python from kida import Environment, DictLoader from kida.analysis.a11y import check_a11y env = Environment( loader=DictLoader({ "page.html": """ <html> <body> <img src="photo.jpg"> <h1>Title</h1> <h3>Skipped h2</h3> <input type="text" name="email"> </body> </html> """ }), preserve_ast=True, ) template = env.get_template("page.html") issues = check_a11y(template._optimized_ast) for issue in issues: print(f"Line {issue.lineno}: [{issue.rule}] {issue.message}") ``` Output: ```text Line 2: [html-lang] <html> missing lang attribute Line 4: [img-alt] <img> missing alt attribute Line 6: [heading-order] Heading level skipped: <h3> after <h1> (expected <h2>) Line 7: [input-label] Form element missing associated <label> or aria-label ``` ### CLI ```bash kida check --a11y templates/ ``` ### A11yIssue Each finding is returned as an `A11yIssue` dataclass: | Field | Type | Description | |---|---|---| | `lineno` | `int` | Line number in the template source | | `col_offset` | `int` | Column offset | | `rule` | `str` | Rule identifier (`img-alt`, `heading-order`, `html-lang`, `input-label`) | | `message` | `str` | Human-readable description of the issue | | `severity` | `str` | `"error"` or `"warning"` (default: `"warning"`) | Results are sorted by `(lineno, col_offset)`. ### Build System Integration Integrate accessibility linting into a build pipeline to fail on errors: ```python from kida import Environment, FileSystemLoader from kida.analysis.a11y import check_a11y env = Environment( loader=FileSystemLoader("templates/"), preserve_ast=True, ) errors = [] for template_name in env.loader.list_templates(): template = env.get_template(template_name) issues = check_a11y(template._optimized_ast) for issue in issues: errors.append((template_name, issue)) if errors: for name, issue in errors: print(f"{name}:{issue.lineno} [{issue.rule}] {issue.message}") raise SystemExit(1) ``` ## Examples of Violations and Fixes ### img-alt Missing `alt` attribute on an `<img>` tag. ```html  <img src="hero.jpg">  <img src="hero.jpg" alt="Mountain landscape at sunset">  <img src="divider.png" role="presentation"> ``` ### heading-order Heading levels must increase by one. Skipping from `<h1>` to `<h3>` is a violation. ```html  <h1>Page Title</h1> <h3>Subsection</h3>  <h1>Page Title</h1> <h2>Subsection</h2> ``` ### html-lang The `<html>` element must declare a language. ```html  <html>  <html lang="en"> ``` ### input-label Form elements need an associated label. The linter accepts any of: a `<label>` with a matching `for` attribute, `aria-label`, `aria-labelledby`, or `title`. ```html  <input type="text" name="email">  <label for="email">Email</label> <input type="text" name="email" id="email">  <input type="text" name="email" aria-label="Email address">  <input type="hidden" name="csrf_token" value="abc"> ``` ## Configuration The `check_a11y()` function runs all rules unconditionally. To filter results by rule or severity, post-process the returned list: ```python issues = check_a11y(template._optimized_ast) # Only errors errors = [i for i in issues if i.severity == "error"] # Exclude specific rules filtered = [i for i in issues if i.rule not in {"heading-order"}] # Group by rule from itertools import groupby by_rule = {k: list(v) for k, v in groupby(issues, key=lambda i: i.rule)} ``` To enforce a strict policy in CI, treat all issues as failures: ```python issues = check_a11y(template._optimized_ast) if issues: for issue in issues: print(f" Line {issue.lineno}: [{issue.rule}] {issue.message}") raise SystemExit(1) ``` To enforce only errors (ignoring warnings): ```python errors = [i for i in check_a11y(template._optimized_ast) if i.severity == "error"] if errors: raise SystemExit(1) ``` ## See Also - [[docs/advanced/analysis|Static Analysis]] — Dependency and purity analysis - [[docs/advanced/coverage|Template Coverage]] — Line-level coverage tracking