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

Annotations only give openWorldHint=false and destructiveHint=false; the description adds genuinely non-obvious behavior: the token is delivered by email and never returned to the caller (empty response), rotation invalidates every previously emailed link, and the operation is founder-gated and carries WRITE risk. That is substantial added value beyond the annotations. It stops short of covering failure modes or what happens to the signer record itself.

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 purpose is front-loaded, but a large share of the text is internal gating rationale ('Exposed', 'The earlier reason for holding it closed') that does not help an agent select or invoke the tool. Roughly half the description is noise rather than operational content.

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?

An output schema exists and the description correctly notes the response is empty, so return values are covered. Auth (founder-gated), side effects, and delivery mechanism are disclosed, which is good for a single-parameter tool. The gap is signerId semantics and error handling, which are absent from both description 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 description coverage is 0% and there is a single parameter, signerId, whose format, source, or required-ness the description never addresses (the schema even marks required: 0, which the text does nothing to clarify). The description's references to 'the persisted signer email' and 'that signer' give only indirect context for identifying the signer, so it fails to compensate for the coverage gap.

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 opening sentence gives a specific verb+resource: rotates a signer's token and re-emails the signing link to the persisted signer email. That is concrete and distinct from siblings like signature_create_envelope or signature_void_envelope, though it never explicitly distinguishes itself from signature_run_reminders, which is the nearest neighbor. Clear, but no sibling differentiation in the text.

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?

'Founder-gated' states a precondition, which is useful when-to-use context, but there is no stated condition for choosing this over signature_run_reminders or any other signing tool, and no when-not-to-use guidance. Usage is implied rather than specified.

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