wcagc-mcp

Check a PDF for PDF/UA-1 conformance

check_pdf

Verify a PDF's accessibility by running a machine-verifiable PDF/UA-1 check on a public URL. It evaluates document structure, tags, and reading order, then returns a check ID to poll for results.

Instructions

Downloads a public PDF URL and runs a machine-verifiable veraPDF PDF/UA-1 check (document structure, tags, reading order — not a full WCAG audit). Free tier, counted against the caller's daily quota. Queues the check and returns immediately with an id; call get_pdf_check to poll.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`url`	Yes	A public URL serving a PDF file.

Output Schema

TableJSON Schema

Name	Required	Description
`pdfCheck`	Yes
`standard`	Yes	The standard the checks were run against, e.g. "WCAG 2.1 AA".
`scoringGuidance`	Yes	Binding instruction for the assistant reading this result. Follow it literally.
`coverageDisclaimer`	Yes	Why this result is not a compliance verdict. Always relay it; never present a scan as proof of conformance.

Schema Changelog

Changes observed during successful MCP inspections.

Addedv0.1.2Jul 28, 2026
Removedv0.1.1Jul 25, 2026
Addedv0.1.1Jul 25, 2026

TDQS

A4.7/5.0

Behavior5/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description discloses key non-obvious behaviors beyond the annotations: it downloads a remote URL, consumes free-tier quota, queues the check, and returns immediately with an id instead of a synchronous result. This is exactly the kind of context that helps an agent set expectations and avoid misinterpreting the immediate return.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is three sentences with zero filler. The primary action and scope are front-loaded, followed by quota/cost notes and then the asynchronous behavior plus polling instruction. Every sentence contributes distinct value, and the structure matches the tool's actual workflow.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness5/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a one-parameter tool with an output schema and annotations, the description covers all necessary operational context: URL type, PDF/UA-1 scope, caveat about WCAG, quota counting, async queue behavior, and the follow-up tool to poll. Nothing essential for invoking the tool correctly is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The input schema already fully documents the single parameter, url, with type, format, maxLength, and description. The description only adds 'Downloads a public PDF URL', which mostly repeats the schema's 'A public URL serving a PDF file.' No significant additional parameter meaning is provided, so the baseline score of 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb and resource: 'Downloads a public PDF URL and runs a machine-verifiable veraPDF PDF/UA-1 check'. It also defines the exact scope ('document structure, tags, reading order') and explicitly differentiates from a full WCAG audit, making it easy to distinguish from sibling scanning tools.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description gives clear context on when to use this tool and what it is not for: 'not a full WCAG audit'. It also names the polling alternative, get_pdf_check, and instructs the agent to call it after queuing. This is explicit workflow routing.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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