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

Annotations already cover safety (readOnlyHint=true, openWorldHint=true), so the bar is lower. The description adds genuinely useful context beyond them: it discloses the returned fields and the CC BY-SA 4.0 attribution obligation, which is a behavioral constraint an agent must honor when reusing the text. It stops short of failure modes (nonexistent title, redirects, disambiguation).

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 tight sentences: the first front-loads what is retrieved, the second adds the licensing constraint. No filler, no repetition of schema or annotation content.

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 carries the burden of describing return values, and it does so (extract, short description, URL, last-edit time) plus licensing. It is nearly complete for a read-only, open-world lookup; only error/redirect behavior is left unaddressed.

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% and both parameters (title, lang) are documented in the schema with defaults, pattern, and lengths. The description only repeats 'by title and language' without adding format or edge-case semantics, so the baseline 3 is correct.

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 precise verb+resource+scope: it returns the lead-section summary of a Wikipedia article identified by title and language. It also enumerates what comes back (plain-text extract, short description, canonical URL, last-edit time), so an agent can distinguish it from generic fetch tools like url_to_markdown 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?

The 'lead-section' phrasing implies this returns only the article intro, not the full text, which implicitly signals when another fetch tool is needed, but no alternative or when-not condition is named. There is no guidance on language defaults, missing/disambiguation pages, or when to prefer it over url_to_markdown. Usage is therefore implied rather than stated.

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