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

Annotations already declare readOnlyHint=true, openWorldHint=true and destructiveHint=false, so safety is covered. The description adds genuinely new operational context the annotations cannot convey: a 20/min throttle and the underlying POST /products/getProduct endpoint. Return payload is summarized but not fully detailed, which is acceptable given there is no output schema.

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?

Three short, front-loaded fragments: what it returns, the parameter constraint, then the throttle and endpoint. No filler, and the most decision-relevant information comes first.

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 two-parameter read tool with full annotation coverage and no output schema, the description covers scope, selection constraint, return contents, rate limits, and transport. An agent has everything needed to call it correctly on the first attempt.

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 the baseline would be 3, but 'Give exactly one of sku or code' adds a mutual-exclusivity/one-required constraint that the schema does not express (required list is empty and there is no oneOf). That is real semantic value beyond the structured fields.

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 ('one product by SKU or code') and enumerates exactly what comes back (details plus on hand, available, pending, picked, incoming, in stock). The parenthetical '(not a kit)' plus 'one product' cleanly separates it from skuvault_list_products and skuvault_list_kits without the agent needing to open any schema.

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?

Gives clear selection context: use this for a single product, and explicitly excludes kits, which routes the agent elsewhere. It does not name a specific sibling alternative (e.g. skuvault_get_item_quantities for quantities only), so it falls short of a full when/when-not/alternatives statement.

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