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

Annotations already indicate it is not read-only and not destructive, which matches the described mutation. The description adds useful context: it returns a file_id and a ~1h URL, implying a new file is produced and that the link expires. This goes beyond the schema and annotations without contradicting them.

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?

Two sentences, front-loaded with the primary action, and every clause adds relevant detail. No redundancy or filler.

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?

No output schema exists, but the description states the return type (file_id + URL) and its lifetime. For a simple stamping tool, the essentials are covered: input format, parameters, and output. Minor omissions like error handling are not critical for this use case.

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 value by enumerating the allowed position values and explicitly stating that format supports {n} and {total}. This is more than the schema's generic examples, so it compensates well beyond the baseline.

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 states a specific action ('Stamp a page number') and resource ('every page'), and provides concrete configuration details (position and format tokens). It clearly distinguishes itself from a generic PDF manipulation tool and is not a tautology.

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 makes it clear this is for adding page numbers to PDFs, with position and format options. It does not explicitly name alternative tools or exclusion cases, but the context is unambiguous enough that an agent would know when to select this over siblings like watermark_pdf.

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