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

Beyond the readOnlyHint and openWorldHint annotations, the description discloses a real cost ('Paid $0.01 USDC exact on Base'), the payment destination, the external source APIs, the output restriction to lead extracts, and the CC BY-SA license. These are meaningful behavioral disclosures that help the agent understand side effects, licensing, and external dependencies.

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?

The description is dense and packs payment, purpose, parameters, output scope, and licensing into one compact block with no filler. It is appropriately front-loaded with the cost constraint, but the telegraphic run-on style makes parsing slightly harder than necessary.

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?

Given there is no output schema, the description does a good job of characterizing what is returned ('Lead extract only') and covers cost, input modes, URL handling, language options, and result count. It is missing explicit response-shape details and payment mechanics, but an agent has enough context to invoke the tool 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 coverage is 100%, so the baseline is 3. The description adds value beyond the schema by providing aliases (query=, search=, page=), clarifying the q-or-title relationship, and noting that wikipedia.org URLs are accepted. This is useful extra semantic information, though the schema already documents most parameter details.

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?

The description clearly names the resource and behavior: 'Wikipedia lead summary via public Wikimedia REST + MediaWiki search.' It also distinguishes the two invocation modes, q= for search and title= for direct pages, so an agent can tell exactly what this tool does among unrelated siblings.

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?

It gives explicit usage context for selecting the right input mode: 'q= search or title= page title (wikipedia.org URLs ok).' It also states a key limitation, 'Lead extract only', which implies when this tool is and is not appropriate. It does not explicitly name alternative tools or provide when-not-to-use guidance, so it falls 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.