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

Beyond the annotations, it explains the full lifecycle: the checkout page requires agreeing that Quest+ starts immediately, the purchase is refundable within 14 days only until the recipient opens the gift, and plus turns on automatically after payment (visible via get_quest). It also enumerates the two error codes, which is exactly the behavioral detail annotations cannot convey.

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 key fact (a purchase that returns a checkoutUrl you must give the user) is front-loaded, and later sentences add refund, activation and failure details. The nested parenthetical about the 14-day refund window makes one sentence dense, but no sentence is 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 one-parameter tool with no output schema, the description covers what is returned, how to deliver it to the user, what happens after payment, the refund window, prerequisites, and both failure modes. An agent has everything needed to call it and interpret the outcome.

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?

There is only one parameter, quest_id, and schema coverage is 0%, so the description carries the burden. It implies the id must reference a quest saved in an account, but it never states the expected id format or how to obtain one (e.g., from list_my_quests). This is adequate but leaves a real 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 description names a specific action (a one-time purchase of Quest+) on a specific resource (one quest) and states what the buyer gets: premium themes and a never-deleted quest. It also states the return value (checkoutUrl), which immediately separates it from siblings such as create_quest or update_quest.

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 gives concrete conditions: only for quests saved in an account, and the returned URL must be handed to the user to open in a browser. It also names the two failure conditions (payments_disabled, already_plus), which tells the agent when this call is pointless. It does not explicitly point to an alternative tool, but no sibling offers a comparable purchase flow.

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