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

With annotations only declaring mutability flags, the description carries real weight: no automatic renewal, the x402/Base payment handshake, ledger recording of attempt/payment/entitlement, an authorization code required when the account is full, and the 10-minute code lifetime. 'Reusing the receipt does not buy another pass' usefully qualifies what repeat calls do, subtly refining the idempotentHint=false annotation rather than contradicting it.

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?

Dense and front-loaded with price and scope, then the payment mechanics. Nearly every sentence carries information, but the telegraphic style (fragments like 'A verified payer account groups its devices.') makes the device/account/payment relationship harder to parse than it needs to be.

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, the description covers price, duration, renewal policy, payment protocol, entitlement recording and code lifetime — most of what an agent needs. What the successful call actually returns (entitlement token, device status) 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?

Schema coverage is 100% so 3 is the floor, and the description still adds meaning: codigo identifies the TV device with the network as fallback, and a verified payer account groups its devices. The enum values (mes/trimestre/ano) are only explained by price in the prose, not by the schema's field description, which the description partially compensates for.

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 precise verb+resource+scope: 'Buy a TV pass for 2 devices', with concrete pricing tiers. The 'TV' qualifier separates it from the sibling chat_pass, and '2 devices' communicates the entitlement breadth an agent needs.

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?

Gives a clear trigger context (purchase of TV device access) and an explicit retry procedure on HTTP 402 with the two accepted payment headers. It stops short of naming alternatives such as chat_pass or pricing/billing, and doesn't say when a pass should NOT be bought.

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