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

Annotations only declare readOnlyHint=true, so the description carries the rest and does so well: it discloses the possible status values (pending, completed, declined, cancelled), that pending recipients expose a signing url, and that a completed request yields a sealed, signed PDF. It does not say what happens when no signature request exists, which keeps it from a 5.

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?

A single dense sentence, front-loaded with the core action, with each clause adding distinct return-value information. Slightly long as one sentence but 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?

With no output schema, the description compensates by describing the return payload in detail, and annotations cover the safety profile. For a one-parameter read tool, an agent has everything needed to call it correctly.

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?

Only one parameter, doc_id, and schema description coverage is 100%, so the schema already does the work. The description's phrase 'of a document' loosely maps to doc_id but adds no format or id-type detail beyond the schema.

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 (get the most recent signature request of a document) and enumerates the payload it returns: status, signer/decliner with reason, signing urls, and sealed PDF file_url. This clearly separates it from create-signature-request and cancel-signature-request among the 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?

Usage is implied by the purpose statement, and 'most recent' resolves the ambiguity of multiple requests per document. However, there is no explicit when-to-use/when-not guidance and no sibling (e.g. cancel-signature-request, create-signature-request) is named as an alternative.

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