Output Formats

Horn supports four output formats. Choose the one that best fits your workflow.

Text (default)

Human-readable terminal output with file summaries and failure details.

horn validate document.pdf

document.pdf (PDF/UA-1)
  FAIL  06-001  Document language not set
  FAIL  13-004  Figure missing Alt text (page 3, element Figure)
  PASS  14-002  Heading levels not skipped

1 file, 2 failures, 1 pass

Best for: local development and manual review.

JSON

Structured JSON output with full report details.

horn validate document.pdf --format json

{
  "files": [
    {
      "path": "document.pdf",
      "standard": "pdf-ua-1",
      "results": [
        {
          "rule_id": "06-001",
          "checkpoint": 6,
          "description": "Document language not set",
          "severity": "error",
          "outcome": {
            "status": "Fail",
            "message": "No /Lang entry in document catalog"
          }
        }
      ],
      "error": null
    }
  ]
}

Best for: programmatic processing, custom dashboards, integration with other tools.

SARIF

SARIF v2.1.0 output for GitHub Code Scanning.

horn validate document.pdf --format sarif -o results.sarif

When used with the Horn GitHub Action, SARIF results are automatically uploaded to GitHub Code Scanning, showing accessibility findings directly in pull requests.

Best for: GitHub repositories, security-style workflows.

JUnit XML

JUnit XML format for CI dashboards.

horn validate document.pdf --format junit -o results.xml

Compatible with Jenkins, GitLab CI, Azure DevOps, and other CI systems that support JUnit test reports.

Best for: CI/CD pipelines with existing JUnit report infrastructure.