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

Annotations only say readOnly and openWorld; the description adds substantive context: cost of $0.002 USDC per successful call, x402 payment across Base/Solana/Arc, failed calls not charged, not-found returns search suggestions, and CC BY-SA attribution obligations. These are real operational facts an agent cannot derive from annotations or schema.

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?

Front-loads purpose and return fields, then facts, then licensing and price; nearly every clause carries information. It is dense but organized, with only mild terseness in the 'inception, country, headquarters' enumeration.

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?

An output schema exists, so the return-shape detail is redundant but harmless; safety is covered by annotations. Missing pieces are minor: no guidance on ambiguous titles versus search terms, and no note on language-code fallback behavior.

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 both q and lang are already documented in the schema. The description's 'in any language' and 'by title or search words' restate rather than extend the schema definitions, so the baseline 3 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 retrieval mode ('A Wikipedia page summary by title or search words') plus the exact payload (title, summary, URL, thumbnail, Wikidata ID). That scope cleanly separates it from wikidata and wiki_pageviews siblings without needing their schemas.

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?

Usage is only implied: it describes what data comes back for people/places/organisations, letting an agent infer this is the tool for encyclopedic lookups. There is no explicit when-to-use or when-not-to-use guidance, and no named alternative (e.g. wikidata) for structured-fact-only queries.

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