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 price ($0.03 USDC on Base), the x402 exact scheme, and the two-phase payment behavior (challenge then signed retry). It does not describe pagination or error behavior beyond that, which keeps it short of a 5.

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?

Three dense sentences that front-load the price and then describe the payload and payment flow. Every clause earns its place, though the payment sentence is slightly run-on.

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 payment-gated tool with no output schema, the description names the returned content (answer phrase, words, letters, link) and explains the payment retry mechanism. Locale behavior is left to the schema, which is acceptable given 100% coverage.

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 parameters (locale, type) are already documented with the enum caveat for 'crossword'. The description adds no parameter-level detail, so the baseline 3 for full schema coverage applies.

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 complete/solved acrostic of the day with the answer phrase, words, letters, and a web link. The 'completo/resuelto' framing distinguishes it from the sibling get_today_acrostic, though it never names that sibling 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 clear operating context: without payment it returns a payment challenge, and the agent should retry with a signed payment in _meta["x402/payment"]. It does not explicitly compare against get_today_acrostic or get_today_puzzle_preview, so routing between siblings is left to inference.

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