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

Annotations cover the safety profile (readOnlyHint, openWorldHint), so the bar is lower; the description still adds real behavior: exact file names rank first and it can surface very recently uploaded files. It does not discuss pagination, result limits, or licensing/rate constraints.

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 tight sentences with the core purpose front-loaded, followed by matching behavior and the cross-tool hand-off. Every sentence carries distinct, actionable information.

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 an output schema present, return values need not be explained, and the description still flags the `token` field and its destination parameter. For a single-param read tool this is complete enough to call 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 0% and the single `query` parameter is undocumented in the schema, so the description compensates by explaining that an exact file name is matched specially and ranked first. It stops short of describing other query syntax (e.g., fuzzy text search, case sensitivity).

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 specific verb (Search) and resource (Wikimedia Commons images) with the concrete goal of putting an image on an entry, mirroring the editor's image picker. This is clearly distinguishable from siblings like search_entries, upload_image, and set_entry_image.

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?

Makes clear when to use it (you want an image for an entry) and hands off explicitly to set_entry_image with the `commons_token` param. It does not name alternative routes such as upload_image or upload_image_from_url, so the exclusion guidance is 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.