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

Annotations already declare this is a non-read-only, non-idempotent, non-destructive, closed-world action. The description adds meaningful context beyond them: the resend is gated on the previous text expiring, it targets sole proprietors, and the flow expects the user to reply YES. It does not mention cost, rate limits, or what happens if the prior text has not yet expired.

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?

One sentence, with the audience restriction and expiry condition front-loaded before the action. Every clause 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-param, no-output-schema action with annotations covering the safety profile, the description covers who, when, and the expected user response. Only edge behavior — non-expired prior text, fees, failure modes — is left unstated.

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 takes zero parameters, so there is nothing for the description to disambiguate. Baseline of 4 applies.

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 gives a specific verb (re-send) and a precise resource (the carrier's verification text), plus the exact recovery trigger (24-hour expiry). No sibling in the list does anything similar, so an agent can route here without ambiguity.

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?

It states the precondition clearly: use only after the prior verification text expired at 24 hours, and only for sole proprietors. It does not name an alternative path (e.g., spur_send_sms or restarting registration via spur_submit_texting_registration) for when the user did not receive or respond to the text.

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