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

Goes well beyond the supplied readOnly/openWorld annotations by disclosing source scope, absence of AI synthesis, a $0.005 USDC price with x402 payment rails (Base, Solana, Arc), and that failed calls are not charged. Missing only secondary behavior such as rate limits or error conditions, so it is strong but not exhaustive.

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?

Two sentences, front-loaded with the resource and scope, then the output and pricing. Every clause carries distinct information—no restatement of the title or filler.

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 an output schema present, the description does not need to explain return values, yet it still summarizes them; combined with the source-scope and payment disclosures, an agent has enough to call it correctly. Minor gaps around limits/error handling keep it from a 5.

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% and both parameters (query with length bounds, limit 1-5 default 3) are already documented in the schema. The description adds no parameter-level meaning, 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 ('searches English Wikipedia') plus an explicit scope negation ('not the open web') and lists what is returned (summary text, description, last edit time). An agent can distinguish this from open-web siblings like web_search_turbo and from synthesis siblings like fact_brief_synthesizer 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?

Clear context for when the tool fits: raw Wikipedia sourcing with 'No AI synthesis; the caller reads and combines the sources', which implicitly routes synthesis work elsewhere. It never explicitly names an alternative tool or a hard when-not-to-use condition, 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.