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

With no annotations provided, the description carries the full burden and does disclose notable behavior beyond the schema: the answer hash is returned in lowercase, the hash-based verification mechanic, and the $0.005 per-call cost paid over x402 in USDC. It stops short of describing rate limits, failure modes, or exactly how the hash enables verification in practice.

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 sentences, front-loaded with what is returned and then why the hash matters. The middle sentence leans slightly promotional ('which no other riddle endpoint lets you do'), but every sentence still carries real information.

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?

No output schema exists, so the description must cover return values, and it does: riddle, answer, and lowercase SHA-256 hash. Pricing and payment rail are also disclosed. It is largely complete for a zero-required-parameter content tool, with only minor gaps such as failure behavior when exclude filters exhaust the pool.

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 seed, exclude, language, and difficulty including enum-like defaults. The description only echoes the language and difficulty axes at a high level, adding no syntax or format detail beyond the structured fields, which fits the baseline 3.

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 verb and resource (one riddle by difficulty, in English or Spanish) and explicitly differentiates itself from other riddle endpoints by returning a checkable SHA-256 hash. An agent can tell this apart from content_joke, content_fact, and content_advice 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?

The description gives a clear usage context: the hash lets an agent verify a guess without reading the solution first. It implies when the tool is valuable (answer-checking workflows) but does not state exclusions or alternatives, though no sibling riddle tool exists to route to.

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