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 safety profile is covered. The description adds genuinely useful context beyond that: it does not read or embed any purchased code, and ambiguous products resolve to 'unknown' rather than erroring. That failure-mode disclosure is meaningful extra 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 sentences, both front-loaded and earning their place: the first states the action and the non-reading constraint, the second bounds scope and states the ambiguous-input behavior. No 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?

There is no output schema, so the description carries the return burden, and it does explain the 'unknown' outcome for ambiguous products plus the no-code-embedding guarantee. It stops short of describing the destination's format (URL vs. page payload), a minor gap for a read tool with full annotation and schema coverage.

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% and each parameter carries rich documentation (currency conversion behavior, no silent variant substitution, country not inferred from language). The description adds no parameter meaning beyond the schema, so the baseline 3 is correct.

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+resource: returns the verified official activation destination for an exact variant. The scope boundary ('detailed product instructions remain on the product page') helps separate it from catalogue/product-page tools, but it never names a sibling such as check_activation_country, which would sharpen the distinction further.

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: the description signals this is for looking up an activation destination rather than reading product details, but it gives no explicit when-to-use, prerequisites, or comparison to check_activation_country or get_store_information. An agent must infer which sibling to call.

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