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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, and openWorldHint=false, covering the safety profile. The description adds useful behavioral context by specifying token-scoped results, inclusion of both uploaded and server-written PDFs, and size information. It does not mention pagination or result ordering, but the added scope details are meaningful beyond the 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 a single, front-loaded sentence that conveys the resource, scope, and returned fields without waste. Every phrase earns its place.

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 zero-parameter listing tool with full annotation coverage and no output schema, the description provides enough context: what is listed, whose data is included, and that sizes are returned. Minor gaps around ordering or pagination remain, but nothing essential to invoke the tool correctly is missing.

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 tool has zero parameters, so there is no parameter semantics to explain. The schema is empty and fully described by default, making the baseline score of 4 appropriate.

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 a specific verb ('List') and resource ('PDFs') with useful scope details: PDFs stored for your token, including both uploaded and server-generated files, with sizes. It is distinct from sibling tools like pdf_count or pdf_info conceptually, but it does not explicitly name or differentiate itself from those siblings.

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 implies when to use the tool by describing what it lists, but it provides no explicit guidance on when to choose it over alternatives such as pdf_count, pdf_info, or other PDF-related tools. Usage is inferable but not directly stated.

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