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

Annotations already declare destructiveHint=true, readOnlyHint=false, openWorldHint=true and idempotentHint=false, so safety is largely covered. The description adds genuinely new context: that it uses local WordPress authentication and requires no WooCommerce REST API keys, plus an explicit human-confirmation protocol. It doesn't say what happens if the key is absent, so it stops short of 5.

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?

Three tight sentences, front-loaded with the action and ending with the exclusions that prevent wasted setup work. No filler, no restatement of the title.

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 destructive four-parameter tool with no output schema, the definition covers scope, authentication model and the confirmation gate, which is most of what an agent needs. The remaining gap is behavior on a missing or already-absent key, relevant given idempotentHint=false, but minor.

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%, so all four parameters are already documented, including the confirm gate and the site_id/list_sites precondition. The description adds only the mild clarification that deletion targets a key, which the schema's metaKey description already conveys. Baseline 3 applies when the schema carries the semantics.

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?

A specific verb plus resource plus scope: "Deletes WooCommerce product metadata by key." That distinguishes it from wc_delete_product (the product itself) and wc_delete_product_variation without needing to name them, since the resource noun differs. It stops short of explicitly contrasting with wc_delete_product_meta's siblings such as wc_update_product_meta, so it earns a 4 rather than 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?

It gives one useful procedural rule: ask the user for confirmation before calling with confirm=true. Beyond that it only implies usage (delete a specific meta key); it never says when to delete a key instead of updating it to an empty value, and it names no alternative tool. Adequate but with a real guidance gap.

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