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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive), and the description still adds substantive behavior: read-live data, only on-sale items appear, retired Forge tiers vanish once passes launch, purchasable=false carries an explanatory note, prices are pre-VAT with a three-month minimum, and payment happens on Stripe's page with no agent handling cards.

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?

Front-loaded with the core purpose, and most content earns its place, but it is delivered as one sprawling ~300-word sentence with stacked parentheticals and em-dashes that make the routing and pricing rules hard to extract at a glance.

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 explaining the returned fields and their quoting meaning, plus the payment flow and the boundary against ticket/free/registration offers. Nothing an agent needs to call or interpret this tool correctly is missing.

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?

Zero input parameters, so the baseline is 4. The description instead documents return-field semantics (priceText as the string to quote with likely-currency-first ordering, and the purchasable flag), which is valuable given no output schema exists.

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?

Opens with a specific verb+resource+scope: 'What Pirate Skills sells right now, with prices, read live.' It then enumerates the exact offer types (Pirate Pass, Forge Pass, Captain on Deck) and names the sibling that performs the purchase (create_checkout), so the agent can distinguish it from every other tool in the list without opening the schema.

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 routing in both directions: use this for passes/sessions that 'create_checkout sells', but event tickets come from list_events on the event page, free events via register_for_event, and the free Codex via search_knowledge. The when-not conditions are stated, not implied.

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