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

Goes well beyond the readOnlyHint/destructiveHint annotations: it discloses the exact return shapes, the `withheld_keys` guarantee that omissions are never silent, the permission model, the specific blocked key families (session_tokens, capabilities, user_level), the manage_options gate on `_`-prefixed keys, and the escape-hatch filter name. This is the kind of policy context annotations cannot carry.

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 required/optional parameters and return shapes before the policy detail, which is the right ordering. The auth/policy sentence is long and dense, but each clause conveys a distinct restriction an agent needs, so little is wasted.

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?

There is no output schema, and the description compensates fully by specifying both return object shapes and the meaning of `withheld_keys`. Combined with the permission and key-blocking rules, an agent has everything needed to call this correctly and interpret the result.

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 schema already documents `user_id`, `key`, `single`, and `site_id`. The description restates the same `key`/`single` semantics rather than adding new detail (e.g., expected key format or prefix behavior), so the baseline 3 applies.

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 ("Reads user meta for a given user") and immediately scopes it by the two modes (single key vs. all meta), which distinguishes it from siblings like wp_get_post_meta, wp_get_term_meta, and wp_get_user. An agent can select it 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 concrete selection guidance: omit `key` to fetch all meta, `single` only matters when `key` is supplied, and users can read their own meta without `edit_users`. It does not explicitly name a sibling alternative (e.g., wp_get_user for profile fields), so it stops short of full when/when-not routing.

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