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

Annotations already declare readOnlyHint=true, idempotentHint=true and destructiveHint=false, and the second sentence merely restates that read-only status ('its server marks it read-only, so it runs straight away'), adding little new information. The genuinely useful addition is the enumeration of what comes back, but there is no mention of pagination, result size, or what happens on an unreachable site.

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?

Two short sentences, front-loaded with the resource and return fields. The trailing clause about Royally's read-only server is mild filler because the annotations already say so, but it costs little.

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?

This is a simple read-only list with one optional enum-constrained parameter and no output schema, and the description compensates by naming the exact fields returned. Nothing critical is missing for an agent to call it correctly, though a note on scope (single site vs fleet) would round it out.

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?

Only one optional parameter and schema description coverage is 100%, so the schema already carries the site_id enum and its human-readable target URL. The description adds nothing about the parameter, which is acceptable given full coverage but is not a value-add.

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 ('Lists installed themes') and enumerates the returned fields (version, active status, parent, update availability). The word 'installed' implicitly separates it from directory-search siblings like emcp-tools-search-themes, but it never names a sibling explicitly, so the boundary with wp_list_themes or wp_get_themes is left 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?

Usage is only implied: an agent can infer this is the tool for auditing what themes exist on a site. There is no statement of when-not to use it, no mention of the near-duplicate theme-listing tools in the sibling set, and no prerequisite/context guidance.

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