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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=true, so the safety profile is covered. The description adds genuinely new information beyond that: the shape of the returned payload (stock per branch, price books, images), which is valuable given there is no output schema. No auth, rate-limit or not-found behavior is described, keeping it short of a 5.

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?

One sentence of substance plus a short endpoint reference, with the identifying constraint ('by id') front-loaded. No filler and nothing that could be cut without losing meaning.

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 tool with no output schema, the field enumeration effectively stands in for a return-value description, which is the main completeness risk here. Error/not-found handling is the only meaningful omission, which is a minor gap.

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 the single parameter is fully documented ('KiotViet product id', positive integer). The description only reinforces 'by id' and does not add format or sourcing details, 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?

"One product by id" gives a specific verb+resource and the following clause enumerates the returned fields (code, barcode, name, category, base price, units, attributes, images, stock per branch, price books), which tells an agent exactly what it gets. The 'by id' qualifier implicitly separates it from kiotviet_get_product_by_code and kiotviet_list_products, but neither sibling is named.

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 endpoint notation GET /products/{id} makes the single-record-by-identifier usage clear by implication. However, there is no explicit statement of when to prefer this over kiotviet_get_product_by_code or kiotviet_list_products, and no note about behavior when the id does not exist.

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