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

Adds rich context beyond the annotations: pricing ($0.003/call via x402 USDC or card key, first 25 free, failed calls free) and read-vs-charge semantics. Crucially it reconciles the otherwise-confusing readOnlyHint=false by stating 'Reads or computes only; not marked read-only because each call is charged.'

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 the purpose, then usage, return fields, a concrete example, pricing, and the annotation rationale. Every sentence carries information; nothing is redundant padding.

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 listing the returned fields, and it covers cost, example invocation, and the read-only/hint nuance. An agent has everything needed to select and call it correctly.

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 title and lang (with the 'default en' note). The description reinforces this with the title=Stockholm, lang=en example, but adds no format or constraint detail beyond the schema, 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 verb and resource ('Short summary of a Wikipedia article') and enumerates exactly what it returns: title, one-paragraph extract, description, thumbnail, page URL. It is clearly distinguishable from sibling tools like dictionary, summarize, and papers, and even supplies a concrete example (title=Stockholm, lang=en).

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 usage context: 'Use to ground an agent's answer in a quick, citable fact sheet,' plus a worked example. It does not name when-not-to-use or a specific alternative sibling, so it stops short of a 5.

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