Check structural accessibility over NextPDF Connect (Pro)
At a glance
Section titled “At a glance”Run structural accessibility analysis over NextPDF Connect. Use
check_accessibility, verified against the Pro tool provider, which registers
new CheckAccessibilityTool() under the protocol name check_accessibility.
The tool’s description defines its scope: it analyses a PDF’s structural
accessibility — headings, tables, images, and reading-order indicators. It
returns indicators and remediation hints. It does not certify Portable
Document Format/Universal Accessibility (PDF/UA) or Web Content Accessibility
Guidelines (WCAG) conformance. A conformance checker makes that determination,
such as veraPDF or a PDF/UA test tool. check_accessibility is a Pro-tier
tool. NextPDF probes it with class_exists() at boot and registers it only
when the Pro package is installed.
Install
Section titled “Install”composer require nextpdf/servercomposer require nextpdf/proBind a transport, then confirm the tool with diagnostic.capabilities.
Conceptual overview
Section titled “Conceptual overview”Accessible structure depends on two things: a logical structure tree of
structure elements (ISO 32000-2 §14.7) and a declared document language, set
through the catalog Lang entry (ISO 32000-2 §14.9; PDF/UA-2 §8.4.4).
check_accessibility inspects these structural indicators and returns findings
with severity and remediation guidance. Treat any numeric score or pass/fail
value in the report as an indicator summary, not a certification. Use it
for triage.
API surface
Section titled “API surface”| Tool | Tier | Role | Risk tier |
|---|---|---|---|
create_pdf, add_text | Core | Build content to inspect | Safe / Caution |
check_accessibility | Pro | Structural accessibility analysis | Safe |
output_pdf | Core | Render and return the PDF | Approval Required / Review (base64) |
Tool names are the registry protocol names. The tool catalog is the catalog of record. The installed tier determines which tools are available.
Code sample — Quick start
Section titled “Code sample — Quick start”create_pdf→ add content withadd_text.check_accessibilitywith thedocument_id.- Review the findings: severity, the indicator, the affected page, and the remediation hint.
- Optionally
output_pdf(base64) for manual review alongside the report.
Code sample — Production
Section titled “Code sample — Production”Treat the report as triage input, not a verdict. Map each finding to a concrete
fix: enable tagged output, set the document language, and add heading
structure. For a conformance gate, run an external checker. Treat that verdict,
not this tool’s score, as authoritative. Run the check before output_pdf with
destroy: true, or it cannot see the document.
Edge cases & gotchas
Section titled “Edge cases & gotchas”- No content. A blank document returns a no-content finding, not a certification.
- Large document. A timeout bounds analysis; split or range large inputs.
- Destroyed session. Run the check before output destroys the session.
- Encrypted source. Supply the password.
- Pro absent. With Core only,
check_accessibilityis not registered.
Performance
Section titled “Performance”The timeout in the budget bounds the analysis. The profile is semantic: the
report is structural-analysis output, so compare findings, not byte output.
Security notes
Section titled “Security notes”The report describes structure, not content secrets. The document under analysis may still be sensitive, so keep it within your trust boundary. The analysis path does not write to the filesystem.
Conformance
Section titled “Conformance”| Statement | Spec | Clause | reference_id |
|---|---|---|---|
| Logical structure is a tree of structure elements. | ISO 32000-2 | §14.7 | |
Document language is declared via the Lang entry. | ISO 32000-2 | §14.9 | |
| Natural language must be specified for accessible authoring. | PDF/UA-2 | §8.4.4 |
check_accessibility reports structural indicators that support accessible
authoring. It does not assert PDF/UA or WCAG conformance. An independent
checker determines that.
Commercial context
Section titled “Commercial context”check_accessibility is a Pro-tier tool. NextPDF registers it only when the
Pro package resolves at server boot.
PDF/UA-2 mapping
Section titled “PDF/UA-2 mapping”The structural indicators this tool inspects align with PDF/UA-2 authoring needs: a tagged structure tree (ISO 32000-2 §14.7) and a declared document language (PDF/UA-2 §8.4.4). The tool reports whether these indicators are present or absent. A PDF/UA checker determines PDF/UA-2 conformance, not the tool’s report.
Tag → ISO 32000-2 §14 cross-reference
Section titled “Tag → ISO 32000-2 §14 cross-reference”Heading and table findings correspond to logical-structure elements in the ISO
32000-2 §14.7 structure tree. The language finding corresponds to the §14.9
Lang entry. The tool reports whether these structural anchors are present. It
does not validate every §14 tag rule; that is a checker’s job.
WCAG 2.2 mapping
Section titled “WCAG 2.2 mapping”Contrast and reading-order findings relate to WCAG success criteria, such as contrast and meaningful sequence. The tool reports indicator values, such as a measured contrast ratio. A WCAG conformance claim requires a full WCAG evaluation, which this tool does not perform and does not assert.
Transport availability
Section titled “Transport availability”| Transport | Available | Notes |
|---|---|---|
| MCP (stdio) | Yes (Pro) | The report is a tool result. |
| REST | Yes (Pro) | The report is the response body. |
| gRPC | Yes (Pro) | Unary; report in the response message. |
HITL risk tier
Section titled “HITL risk tier”check_accessibility is Safe (read-only analysis) and never gates.
output_pdf to a file is Approval Required, and base64 mode is Review
(HITL risk tiers).
Confirmation gate JSON envelope
Section titled “Confirmation gate JSON envelope”The analysis never gates:
{ "allowed": true }