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

Adds meaningful context beyond annotations by disclosing the pay-per-call cost model ($0.001 USDC on Base via x402), which explains why readOnlyHint=false despite this being a data lookup — the side effect is financial. It does not mention rate limits or latency, but the cost disclosure is the critical behavioral fact.

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 tight clauses: what it returns, when to use it, what it costs. Front-loaded with the payload and free of filler; every sentence earns its place.

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, the description compensates by enumerating the return fields, and it discloses the payment prerequisite an agent must know before invoking. Nothing needed to call it correctly is missing.

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 (lang, title) are already documented. The description reinforces 'any language edition' and the title-based lookup but adds no syntax or format detail beyond the schema. 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 verb and resource ('Short summary of a Wikipedia article') and enumerates the exact payload (title, extract, description, thumbnail, page URL). An agent can distinguish this from siblings like summarize, papers, or extract without opening any 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?

'Use to ground an agent's answer in a quick, citable fact sheet' gives clear when-to-use context. It does not name alternatives (summarize/papers) or state when-not to use it, so it falls short of the explicit routing a 5 requires.

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