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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is fully covered without the description. The description adds useful scoping context ('in the active theme'), which tells the agent that results are theme-bound rather than site-wide, but it says nothing about result size or pagination.

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?

A single well-formed sentence that front-loads the verb and resource with no filler. It is appropriately sized for a simple two-parameter read tool, though it leaves no room for any qualifying detail.

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 read-only listing tool with 100% schema coverage, no nested objects and no output schema, the description plus schema covers what an agent needs to invoke it correctly. Only minor gaps remain, such as whether results are paginated or how many templates a typical theme returns.

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%, and the schema itself documents both site_id (including the 'call list_sites first' instruction) and the type enum. The description only restates the enum's meaning in prose ('block templates or template parts'), adding little beyond the structured fields, 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?

The description gives a specific verb (Lists) and a precisely scoped resource (block templates or template parts in the active theme), which is enough to separate it from siblings such as wp_list_blocks or wp_list_posts. It does not explicitly name a sibling to contrast against, so it stops short of a 5.

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?

There is no when-to-use or when-not-to-use guidance in the description, and no alternative tool is named. The use case is only implied by the word 'Lists'; the prerequisite to call list_sites first lives in the schema, not the description, so it does not help here.

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