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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and non-destructive behavior. The description adds value by specifying the exact return fields (titles, page IDs, snippet, size, timestamp, URL), the data source (commons.wikimedia.org), and that no authentication is required. The 'stripped text snippet' note is a useful nuance beyond 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 three sentences with no fluff. It front-loads the core action, then lists return fields, and finally gives a follow-up recommendation and data source. Every sentence contributes useful information, making it appropriately sized and well-structured.

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?

Given the presence of an output schema, the description still lists key return fields, which is helpful. It covers the data source, authentication requirement, and a follow-up tool for richer metadata. For a two-parameter search tool, this is complete; nothing an agent needs to call it correctly 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?

The input schema covers both parameters (query and limit) with descriptions, achieving 100% schema description coverage. The description's phrase 'by keyword' aligns with the query parameter but doesn't add extra semantics beyond the schema. Since schema coverage is high, the baseline of 3 applies; the description adds no additional parameter-level 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?

The description clearly states the action (search by keyword), the resource (Wikimedia Commons media), and the scope (images, audio, video). It also enumerates the returned fields, making the tool's purpose unambiguous. While it doesn't explicitly name sibling alternatives, the verb and resource differentiate it from category browsing or random selection.

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 provides clear context that this is the keyword search entry point and explicitly recommends following up with wikimedia-commons.file_info for full metadata. It doesn't explicitly state when not to use this tool or mention alternatives like media.category or media.random, but the follow-up guidance and the 'by keyword' framing give sufficient usage direction.

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