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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the bar is lower. The description adds real value beyond them by disclosing the authentication model: local WordPress auth, no WooCommerce REST API keys needed, which tells an agent this will work in an already-connected site context.

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, front-loaded with the operation. The implementation-mirroring note is slightly meta but earns its place by explaining the auth path; nothing is redundant.

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?

A simple two-parameter read tool with full annotation coverage, complete schema descriptions, and no output schema requiring explanation. The only small gap is that it does not characterize the shape of the returned tax rate record, which is minor for a single-resource getter.

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 rateId and site_id are fully documented in the schema, including the important warning not to pass a URL or post ID. The description adds no parameter-level meaning beyond that, so 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: 'Gets one WooCommerce tax rate.' The word 'one' signals single-record retrieval, implicitly contrasting with the plural list sibling, though it never names wc_get_tax_rates explicitly.

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?

Usage is only implied: fetching a single tax rate by ID. There is no explicit when-to-use versus wc_get_tax_rates or the create/update/delete siblings; the only routing guidance ('Call list_sites first') lives in the schema, not the description.

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