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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is established. The description adds value by specifying the exact artifacts it will not create (invoice, checkout, payment), which is concrete context beyond the generic hints. No contradiction between description and annotations.

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 sentences totalling 13 words, with the core purpose front-loaded in the first sentence. Every word earns its place; the second sentence is a precise exclusion rather than filler.

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 one-parameter read-only tool the core is covered, but with no output schema the phrase 'purchase directions' leaves the return format undisclosed (plain text steps, structured list, URL?). The expected format of the `product` parameter is likewise absent. Adequate but with clear gaps.

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 0%, and the description never mentions the sole required parameter `product`. The agent cannot tell whether to pass a product name, ID, or slug; maxLength/minLength provide no semantic help. The description fails to compensate for the coverage gap.

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 ('Return purchase directions only') with a boundary condition that disambiguates from the name's implication of an actual transaction ('Never creates an invoice, checkout, or payment'). The scope is unambiguous on its own, though it does not explicitly contrast with sibling tools.

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 usage context is implied — this tool is for when a user needs purchase directions — but no explicit when-to-use versus alternatives guidance is given. The negative guarantee ('Never creates an invoice, checkout, or payment') signals it is not for executing purchases, but no sibling is named as the alternative for that need.

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