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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, and the description mainly restates that ('server marks it read-only, so it runs straight away') rather than adding new behavioral detail. It does add the useful default-vs-filtered return behavior, but says nothing about output shape specifics, sensitivity of exposed environment data, or error conditions.

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?

The first two sentences are efficient and front-loaded with the resource and its fields. The third sentence ('Through Royally: its server marks it read-only, so it runs straight away') is awkwardly worded and largely duplicates the readOnly annotation without earning 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?

There is no output schema, so the description carries the burden of explaining returns, and it does name the four field groups returned. Combined with a two-parameter, zero-required schema that is fully documented, an agent has enough to invoke it correctly; only sibling disambiguation 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?

Schema coverage is 100%, so both the optional 'fields' enum and the fixed 'site_id' are fully documented in the schema. The description's 'By default returns all fields, or optionally a filtered subset' merely echoes that, 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?

States a specific verb and resource ('Returns core details about the site's runtime context') and enumerates the data returned (environment, PHP runtime, database server info, WordPress version), so the agent knows exactly what it gets. It does not, however, distinguish itself from close siblings such as core-get-site-info or wp_ability_core_get_environment_info, which an agent could easily confuse with this one.

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?

'for diagnostics and compatibility' implies the usage context but gives no explicit when-to-use, when-not-to-use, or alternative-selection guidance. With several sibling info/environment tools in the fleet, a routing sentence is the obvious missing piece.

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