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

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so the safety profile is fully covered by structured data. The description adds nothing beyond that — no pagination behavior, no note on result volume or ordering. It restates a read of the library, which the annotations already imply.

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?

A single front-loaded sentence with no waste. It is efficient, though it is arguably too terse to earn a 5 given the tool's six parameters.

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 an all-optional read-only list tool with full schema coverage and no output schema, the description is minimally viable. It omits what the response looks like and any pagination/default context not already in the schema, but nothing critical blocks invocation.

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 all six parameters (page, search, _fields, site_id, per_page, media_type) are already documented in the schema, including the enum and default for per_page. The description adds no syntax or format detail beyond what the schema provides, making the baseline 3 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?

Clear verb+resource: 'List items in the WordPress media library'. An agent can distinguish it from wp_upload_media or stock_photo_search by the resource, but the description names no sibling and does not clarify how it differs from other list/search tools like wp_search_content.

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?

'with optional filters' merely hints at how the tool is parameterized; it gives no when-to-use, when-not-to-use, or alternative selection guidance. Nothing tells the agent when to pick this over wp_search_content or stock_photo_search.

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