get_variant

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

With no annotations, the description carries the full burden. It transparently discloses the return fields (price, SKU, barcode, inventory quantity, option values) and the price format (VND, float with 4 decimals). It does not mention error behavior, but for a simple getter this is a solid disclosure.

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?

The description is concise and front-loaded, using two sentences with no redundant information. It immediately states the action and then lists the returned data efficiently.

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 single-parameter getter with no output schema, the description covers the essential behavior and return values. It could mention what happens if the variant is not found, but overall it provides enough context for correct invocation and result interpretation.

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?

The input schema already provides full coverage (100%) for the only parameter, variant_id, with a clear description. The tool description adds 'by ID' but doesn't enrich the parameter semantics beyond what the schema already states. Baseline 3 is appropriate.

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?

The description clearly states 'Get a single product variant by ID' with a specific verb and resource. It distinguishes itself from sibling tools like 'list_variants_for_product' by indicating it retrieves exactly one variant by its identifier, not a list.

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 description makes the usage context clear: use this when you need a single variant by its ID. It does not explicitly mention alternatives or when not to use it, but the 'single... by ID' wording provides enough guidance to select it over listing tools.

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