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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint, so "read-only, runs straight away" adds little beyond the structured fields. The genuinely additive content is the enumeration of returned fields, which is valuable given there is no output schema; no pagination or volume limits are mentioned.

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?

Purpose, return shape, and the alternative are front-loaded in the first three sentences with zero waste. The trailing "Through Royally: read-only, runs straight away" is boilerplate that duplicates the annotations and could be cut.

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 simple, no-required-parameter read tool with no output schema, the description supplies everything an agent needs: what it lists, what each entry contains, and where to go for active-theme detail. Annotations carry the safety profile, so nothing material 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?

There is a single site_id parameter with 100% schema description coverage and an enum containing one site, so the schema fully documents it. The description's parenthetical site note merely restates the schema's enum description, adding no new semantics — 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 ("List all installed themes") and enumerates the returned fields (slug, name, version, author, active flag). It explicitly names the sibling wp_get_active_theme and the boundary between them, so an agent can distinguish them without opening a 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 an explicit alternative ("Use wp_get_active_theme for details on the currently-active theme only") with the condition that selects it, which is the main routing decision for a theme-listing tool. It stops short of stating other cases (e.g. when to prefer wp_get_theme_mods or a cross-site inventory tool), so it is clear but not exhaustive.

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