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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds real behavioral context beyond that: the link opens the store with the product pre-selected, and the product must already be published — which explains why a call might fail.

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, zero waste, with the core return value front-loaded and the prerequisite/provenance note following. Nothing 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?

For a simple, read-only, two-parameter tool with a 100% documented schema and no output schema, the description covers input provenance, preconditions, and the shape of the return value (a link). No significant gaps remain.

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 both parameters are fully documented in the schema, establishing a baseline of 3. The description restates the agent_key provenance already present in the schema and adds only the implicit constraint that product_id must refer to a published product.

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?

Specific verb+resource: it returns a purchase link for a published product, and clarifies what the link does when opened (store with product selected). This is clearly distinguishable from sibling read tools like list_products or sales_summary, though no sibling is named explicitly as a contrast.

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?

States the prerequisite that the product must be published and tells the agent where the required agent_key comes from (open_store), which implicitly routes the agent through the correct preceding tool. No explicit when-not or alternative tool is named, but the usage context is clear.

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