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

Goes well beyond the readOnlyHint annotation: discloses capability gating (meta_query needs edit_posts, non-publish statuses need edit_others_posts/read_private_posts), which filters are refused for non-author/non-hierarchical types, and that raw_columns only applies in edit context. The scope-permission detail in 'edit: only items you can edit' vs 'view: items you can read' is exactly the kind of context an agent cannot get from 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 required parameter is correctly front-loaded and the long parameter enumeration is at least ordered by importance. But it is one dense paragraph, and it ends with malformed text ('Returns { items: [{ id, title, status, date, modified, link… Through Royally: its server marks it read-only') that appears truncated and garbled, wasting the most structurally important slot.

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 24-parameter WP_Query-style lister with no output schema, it covers discovery of rest_base, permission gates, filter conflicts, and defaults. The one real gap is the return shape, which is announced then cut off mid-sentence, leaving the agent without a reliable picture of the response payload.

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 every parameter already carries its own description with defaults, limits, and enum values; the prose largely restates that list. It adds marginal value by flagging mutually exclusive pairs and the meta_query permission rule, but not enough to exceed the baseline for a fully documented schema.

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?

Opens with a specific verb+resource and a real scoping constraint: 'Lists items of any custom post type (CPT) registered with show_in_rest=true.' That implicitly separates it from wp_list_posts/wp_list_pages, and it names wp_get_post_types as the way to resolve a slug. It never explicitly names the sibling it replaces for built-in post types, so differentiation is left partly to inference.

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 guidance on getting the required rest_base ('wp_get_post_types lists every post type with its slug and rest_base') and explains the context choice between edit and view. It states mutual exclusions (include/exclude, parent/parent_exclude) but never says when to prefer this over wp_list_posts or wp_search_posts, so exclusions are absent.

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