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

Annotations already declare this a read-only, idempotent, non-destructive, closed-world operation, so the safety profile is covered. The description adds genuinely useful context the annotations cannot convey: it uses local WordPress authentication and requires no WooCommerce REST API keys. However, it says nothing about what is returned (e.g. enabled vs disabled gateways, whether credentials/settings are exposed), which is the remaining behavioral unknown for a retrieval tool.

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 short sentences with the core action front-loaded and no filler. The second sentence mixes an implementation reference with a genuinely useful auth constraint, which slightly dilutes focus but still 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 simple single-parameter read tool with full annotation coverage, a fully documented schema, and no output schema, this is largely sufficient. The only gap is that the shape/content of the returned gateway list is not hinted at, which matters mildly for a listing tool.

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?

There is one parameter, site_id, and schema coverage is 100% with an explicit description telling the agent to call list_sites first and not to pass a URL or post ID. The description adds no parameter meaning beyond that, so the baseline of 3 applies since the schema already does the work.

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?

Uses a specific verb and resource ("Retrieves WooCommerce payment gateways"), which is immediately distinguishable from mutation siblings such as wc_update_payment_gateway. It does not explicitly contrast itself with the singular wc_get_payment_gateway, so the plural-vs-single distinction is left to inference from the name.

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?

The description gives no explicit when-to-use guidance, no prerequisites, and no statement of what selects this tool over wc_get_payment_gateway (single gateway) or the update sibling. Only the tool name's plurality implies 'list all', which is weak routing guidance given a very close sibling.

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