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

Annotations already declare readOnlyHint and idempotentHint, and the description adds valuable behavior: defaulting to en.wikipedia.org, supporting project/lang overrides, and returning specific fields (thumbnail, lead paragraph). This goes beyond the structured annotations.

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 compact yet packed: trigger phrases, purpose, usage guidance, defaults, and an example are all covered in two sentences. Every clause earns its place with no wasted words.

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 read-only summary tool with an output schema, the description fully covers the common use case, including language/project options and an example. Return format is already documented by the output schema, so no further detail is needed.

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 meaning by explaining the default project/lang behavior and giving a concrete example (page_summary({ title: "Albert Einstein" })), which shows how parameters combine beyond the schema descriptions.

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 explicitly states "fetches the Wikipedia article extract (title, description, thumbnail, lead-paragraph extract)", giving a specific verb and resource. It distinguishes this from siblings like page_html or page_media by focusing on the summary extract rather than full content or media.

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 provides a clear usage context: "Use whenever an agent needs a quick encyclopedic reference" and gives example query phrases. However, it does not explicitly contrast with alternative sibling tools like page_metadata or page_revisions, so it stops short of full when-not guidance.

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