Validate PDF/UA structure

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

The description discloses behavioral traits beyond annotations: it is 'Read-only', explains the response shape with fields like standard, valid, errors, warnings, summary, and explicitly states what it checks (catalog, per-page MCID) and what it does not check (fonts, colour, rendering). This adds significant context beyond the readOnlyHint and idempotentHint annotations.

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

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

The description is moderately concise (5 sentences), front-loaded with the core purpose, and each sentence adds value. It is not overly verbose for the complexity of the tool, though it could be slightly tightened without losing information.

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

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

Given the presence of an output schema (though not shown in the prompt), the description already details the response shape and key fields. It covers the tool's limitations and prerequisites, making it self-contained and sufficient for the agent to understand the tool's complete behavior without needing additional context.

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

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

Schema coverage is 100%, but the description adds meaning by explaining the verbosity parameter ('summary' vs 'full' and their output differences) and the fields parameter as 'dot-path projection'. This enriches the schema, helping the agent understand how to use each parameter effectively.

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

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

The description clearly states the tool is a 'Read-only PDF/UA (ISO 14289-1) structural conformance check' with specific verb and resource. It distinguishes from sibling tools like 'verify_pdf' and mentions it is not a full reference validator (veraPDF), making it easy for the agent to select the correct tool.

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

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

The description provides guidance on when to use this tool: 'Generate accessible input with any document tool using pdfA (e.g. pdfA='pdfa2u'), then validate the result here.' It contrasts with a full reference validator, implying when not to use it, but does not explicitly list alternatives among siblings beyond the mention of veraPDF.

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