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

Annotations cover the safety profile (readOnly false, destructive false, non-idempotent), so the description adds context beyond them: no invitations are dispatched, the document ID is returned, and re-uploading a known document is discouraged. It doesn't mention size/auth prerequisites, but the schema covers the 25 MiB limit.

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?

Three tight sentences, front-loaded with the core action and return value, followed by the usage rule and the anti-pattern warning. No 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?

For a 3-param upload tool with no output schema, the description supplies the return value (document ID) and the intended workflow, which is what an agent needs to chain into create_assignment. Minor gaps around failure behavior are tolerable given the annotations and schema.

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%, so file_name, account_id, and file_base64 are already fully documented in the schema. The description adds no syntax or format detail beyond it, making the baseline 3 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?

States a specific verb and resource (upload a PDF) plus a key scope qualifier (without sending invitations) and the return value (document ID). This clearly separates it from send_pdf_for_signature and create_assignment.

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?

Explicitly names the when ('prepare a document now and send it later with assinafy_create_assignment') and an anti-pattern ('never upload again when a document ID is already known'). Both the alternative tool and the exclusion condition are stated.

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