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

With no annotations, the description carries the full burden and does well: it discloses the exact price and currency ($0.01 USDC on Base, x402 scheme exact), the no-payment challenge response, and the retry mechanism. It doesn't describe error handling for the crossword enum case or locale fallback, but the payment behavior is unusually well specified.

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?

Two dense sentences with the payment mechanics front-loaded ahead of the content description. Every clause earns its place, though the mixed pricing/x402 jargon makes it slightly harder to parse on first read.

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 and no annotations, the description covers the essentials an agent needs: cost, payment handshake, retry path, and the shape of the returned content. Minor omissions such as failure modes beyond not_available_yet keep it short of a 5.

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 the schema already documents both parameters, including the enum restriction on 'type' and the allowed locale values. The description adds no additional parameter syntax or format meaning beyond the schema, making the baseline 3 appropriate.

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?

States a specific resource and scope: the day's playable acrostic, with 'definiciones + referencias de grilla, respuestas removidas' clarifying what the caller receives. The '(jugable)' qualifier and 'respuestas removidas' implicitly differentiate it from the solved sibling, but that alternative is never named explicitly.

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 concrete operational guidance: without payment it returns a payment challenge, and the caller should retry with a signed payment in _meta["x402/payment"]. It lacks an explicit statement of when to prefer this over get_today_acrostic_solved, but the payment flow guidance is strong and actionable.

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