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

Annotations already declare readOnly, idempotent, openWorld, and non-destructive behavior. The description adds useful behavioral context beyond those flags: 'no auth required' and the upstream data source (commons.wikimedia.org MediaWiki Action API). It does not contradict any annotation.

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 carry the essential information: purpose, return fields, usage flow, data source, and auth requirement. The main action is front-loaded, and every sentence earns its place without fluff or redundancy.

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 single-parameter lookup tool with an output schema, the description covers everything needed: what input to provide, what metadata will be returned, how to use it after related tools, the underlying source, and auth requirements. No critical context 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 single 'title' parameter is fully documented in the schema, including the optional 'File:' prefix. The description restates the title-based lookup and gives an example, but adds little semantic value beyond the schema; the baseline of 3 is appropriate.

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: 'Get full metadata for a specific Wikimedia Commons file by title.' It then enumerates the exact fields returned (download URL, dimensions, size, MIME type, license, etc.), clearly distinguishing this lookup tool from sibling search/category/random tools.

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 clear context: use this after wikimedia-commons.search or wikimedia-commons.category_files to turn a resolved title into a usable, licensed download link. It states when to use the tool and its prerequisite, though it does not explicitly discuss when not to use it or name alternatives to exclude.

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