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

Annotations already flag mutation and destructiveness, and the description adds substantive context on top: the edit_theme_options capability requirement, WP_Error on duplicate names, the undo path deleting an empty menu, and the Royally human-approval gate that blocks site changes until approved. That approval gate is critical behavioral information an agent could not infer 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?

Front-loaded with the action, then layered with capability, error, undo, and approval details in a compact block. The trailing site parenthetical is mild boilerplate, but overall there is little waste.

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 by specifying the return value (menu_id) and the error condition (WP_Error on duplicate name). Combined with the permission, undo, and approval notes, an agent has everything needed to call this correctly.

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% with only two parameters, so the schema already documents name uniqueness and site_id. The description adds no format or syntax detail beyond the schema, so 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 ("Create a new WordPress navigation menu") and distinguishes itself from siblings by noting the returned menu_id feeds wp_create_menu_item / wp_reorder_menu_items. It also names the underlying WordPress function, so an agent can map it to known behavior.

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 an explicit condition for use ("Use this on a site that has no menus yet so the menu-item tools have a menu to write into") and names the downstream tools it enables. This is a genuine when-to-use rule rather than a restatement of the name.

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