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

Annotations already signal readOnlyHint=true, so the safety profile is covered. The description adds useful context by naming the exact information categories returned, but it does not disclose output format, behavior on corrupted or encrypted PDFs, or any limitations beyond the annotation-provided read-only hint.

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 compact and front-loads the tool's purpose before listing the returned data fields. The leading 'PDF File Info' is somewhat redundant with the tool name/title, but the rest of the sentence offers specific value and the category tag is useful for organization.

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?

For a one-parameter, read-only informational tool with no output schema, the description adequately conveys what the tool returns. It does not cover edge cases or return formatting, but the operation is simple and the annotations already establish the read-only nature.

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?

The only parameter, file, is fully documented in the input schema as 'Input file (PDF)', giving 100% schema coverage. The description adds no additional parameter-specific meaning or constraints beyond what the schema already states.

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 identifies the resource (a PDF) and the operation (retrieving detailed info), and enumerates the specific data points returned: size, pages, version, and encryption. It does not explicitly contrast with siblings like pdf_get_metadata or analyze_pdf_inspector, but the listed fields make the scope reasonably clear.

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 no guidance on when to use this tool versus sibling alternatives such as pdf_get_metadata, pdf_page_count, or analyze_file. The [category: pdf] tag offers a broad grouping but no selection criteria, exclusions, or alternative recommendations.

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