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

Goes well beyond the readOnly/idempotent annotations: it names the exact readable key set, the permission prerequisites (list_users plus edit rights on the user and each field, administrators in standard roles), and the not-found behavior for an unknown user_id. It also documents both return shapes, which annotations cannot convey.

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?

Front-loads purpose and the allowed key list, then permissions, error behavior, and return shapes in a compact single block. Slightly dense, and the trailing forwarding note is contextual rather than essential, but no sentence is filler.

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 no output schema, the description supplies the return shapes, the constraint set, the authorization requirements, and the error case. There is nothing an agent needs in order to call this correctly that 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 coverage is 100%, so baseline is 3, but the description adds real semantic value by enumerating the only legal values for 'key' and restating that omitting it reads all fields. The user_id hint ('authors' ids appear in wp_list_posts and wp_get_post') is carried by the schema, not the description.

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 and resource ('Get standard profile fields (user meta) of one user') and immediately bounds scope: one field or all of them, from a fixed key list. An agent can tell this apart from wp_get_user or wp_update_user_meta without opening the schema.

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?

Gives clear when-to-use context and an explicit exclusion: only the enumerated non-sensitive keys are readable, any other key is refused with that list. It stops short of naming alternatives (e.g. wp_get_user for other user data), so it is clear but not fully routing.

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