Specs and comparison

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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds genuinely useful behavior beyond that: how spec rows align one value per product id, that a missing id yields no value, and that invalid ids surface in not_found.

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 tight sentences, zero filler. The core action and cardinality lead, followed by use cases, then edge-case behavior — well front-loaded and appropriately sized for a single-parameter tool.

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?

With an output schema present, return formatting need not be explained, yet the description still covers the two things an agent would otherwise guess wrong: row alignment and not_found handling. Annotations carry the safety profile, so nothing material is missing.

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% and the schema already documents the 1-4 id array with an example, so the baseline is 3. The description adds real semantics on top: the positional contract between product ids and each spec row, and the silent-omission behavior for ids lacking a value.

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: 'Get the specification table of 1-4 products side by side, with each product's stock count.' The '1-4 products side by side' framing implicitly separates it from the single-product sibling mk_product, but no sibling is named explicitly, so it falls short of the 5 benchmark.

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 concrete trigger phrasings: 'Use for "battery life / Bluetooth version of X" or to compare products row by row.' That is clear when-to-use context, but there is no when-not-to-use guidance or explicit routing to alternatives such as mk_product or mk_filters.

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