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

Annotations declare non-read-only, non-idempotent and open-world, and the description adds real context beyond them: the $1 USDC cost, the wallet requirement and editToken fallback, the 90-day stacking cap, the consequence of lapse (site deleted, slug freed), and a card/PromptPay fallback via the 402 payment_url with a poll-preview_status recovery loop. It is consistent with, not contradictory to, the annotations (each call adds 30 days, so non-idempotent fits).

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?

Purpose, price and credential are front-loaded in the first clause, and every following sentence adds a distinct rule (eligibility window, expiry consequence, payment fallback). It is dense and slightly long, with the support email and payment walkthrough adding some bulk, but nothing is truly 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 paid mutation tool with no output schema and no local-state annotations, this covers cost, credentials, eligibility, lapse consequences and the non-crypto payment path with recovery polling. The only remaining gap is what a successful renewal returns or how the added days are confirmed.

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 100%, so both slug and editToken are already documented in the schema, and the description largely restates them ('Same claiming wallet (or editToken for a card-paid site)'). The baseline of 3 applies because the schema carries the parameter semantics.

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 first sentence states a specific verb and resource with the exact effect and price: 'Renew hosting +30 days for $1 USDC'. It also names the credential options (same claiming wallet or editToken), which clearly separates it from the sibling claim tool that creates a site.

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?

Explicit preconditions are given ('only while the site is live and remaining < 90 days, stacked cap 90') and an explicit exclusion with the alternative named ('after expiry renew is unavailable — claim again as a new site'). An agent knows exactly when to call this versus claim.

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