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

Annotations already cover the safety profile (readOnlyHint=true, destructiveHint=false), and the description goes beyond them by disclosing setup prerequisites: plugin transport, ACF active on the site, and Xyle Connector v0.2.3+. It does not discuss failure modes when ACF is inactive or how the detail flag changes results, but this is a meaningful addition over structured fields.

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 compact sentences: the first front-loads purpose plus return shape, the second carries usage and prerequisites. No filler, and the arrow notation compresses the output contract efficiently.

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?

With no output schema, the description compensates by naming the returned object shape, and it covers usage and prerequisites. What remains thin is behavior when ACF is absent or the post lacks fields, and the effect of detail on the returned field set.

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% with 3 parameters, so site_id, post_id and the detail verbosity flag are already documented in the schema. The description adds only the output shape, not parameter-level meaning, 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 ("Read the Advanced Custom Fields (ACF) values on a page/post") and even sketches the return shape ({post_id, fields:{name:value}}). It is immediately distinguishable from wp_set_acf and other wp_get_* siblings by naming the exact resource domain.

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?

Explicitly says to use it "before wp_set_acf to see current field names/values," tying the read to a concrete workflow and naming the companion tool. No when-not-to-use or alternative read path is offered, so it stops short of full routing guidance.

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