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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds one useful behavioral fact — it returns the lead section only, not the full article — but says nothing about behavior on near-miss titles, redirects, or disambiguation pages, which matters for an exact-title lookup.

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?

One front-loaded sentence with zero filler; the resource and the key constraint both land immediately.

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?

For a one-parameter read with no output schema and annotations covering safety, this is nearly sufficient — it tells you the input shape and that output is the lead summary. Only the failure mode for inexact titles is 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?

Single parameter with 100% schema coverage and an inline example ('Cloudflare'), so the schema carries the load. The description reinforces the exact-match requirement, which is the one semantic that could trip an agent up, but adds no formatting or case-sensitivity detail.

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?

Specific verb + resource ("Get the lead summary of a Wikipedia article") with the constraining qualifier "by exact title". This implicitly separates it from the sibling wikipedia_search, though it never names that alternative explicitly.

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?

"by exact title" implies the precondition that you already know the title and that this is a lookup, not a discovery tool. However, no explicit when-to-use statement and no reference to wikipedia_search for the find-the-title-first case.

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