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

Annotations already declare this as read-only, idempotent, and non-destructive; the description adds useful behavioral context beyond those: 'No auth required' and licensing attribution ('Data: Wikipedia contributors, CC BY-SA 4.0'). It does not contradict 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?

Three compact sentences with no filler: the first states the action and result, the second gives the use case and auth requirement, and the third provides licensing. Every sentence earns its place.

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 low-complexity, two-parameter read-only tool with a fully documented schema and an output schema, the description covers the necessary invocation context: what is returned, when it is useful, and that no auth is required. Nothing essential is missing.

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%, so the schema already documents the title format, underscore usage, language code length, and default. The tool description adds general output content but no additional parameter-level semantics, which is acceptable at the baseline.

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 opens with a specific verb and resource: 'List all images and media files embedded in a Wikipedia article.' It also enumerates the returned fields (file titles, type, srcset URLs, captions), making it clearly distinct from sibling tools like wikipedia.article.summary or wikimedia-commons.media.search.

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 description gives a clear intended use: 'Useful for enriching responses with article visuals.' It does not explicitly name alternatives or state when not to use it, so it stops short of the top score, but the context is sufficient for an agent to recognize the right scenario.

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