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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, so the safety profile is covered in structured data. The description adds only a light restatement ('read-only, runs straight away') plus the site binding, and says nothing about return shape, size, or whether serialized PHP values come back as-is.

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?

One front-loaded sentence states the resource and scope immediately. The trailing 'Through Royally: read-only, runs straight away' is slightly promotional but does carry a small reassurance payload, so it mostly earns its place.

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 zero-required-parameter read against a single known site, with annotations covering safety and a fully documented schema, the description gives an agent everything needed to call it correctly. No output schema exists, but 'get all customizer settings' adequately sets expectations for a raw key/value dump.

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?

The single site_id parameter has fully documented schema coverage including an enum and human-readable URL, so the schema does the work. The description repeats the target site inline but adds no semantics (e.g. that omitting it defaults to the only configured site) beyond structured fields, matching the baseline for high coverage.

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?

Names a specific verb and resource: 'Get all customizer settings (theme_mods) for the active theme,' which clearly separates it from write siblings like wp_update_theme_mod. It does not explicitly differentiate itself from adjacent reads such as wp_get_custom_css or wp_get_global_styles, 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?

'Runs straight away' implies the tool is safe to invoke without confirmation, and the read-only framing hints at the use case. However, there is no explicit statement of when to prefer this over wp_get_global_styles, wp_get_custom_css, or wp_get_active_theme — usage must be inferred from the resource name.

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