Similar products

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

Annotations already declare readOnly/idempotent/non-destructive, so the bar is lower; the description still adds real value by disclosing the result shape (lowest price, shop count), the currency unit (Toman), and the quality caveat that matches are only loosely related. The remaining gap is pagination/ordering behavior, which is minor given the schema covers paging.

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 short sentences with zero filler, and the definition of what is returned is front-loaded before the usage advice. Every clause carries actionable information.

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 no output schema and only three simple parameters, the description does the necessary work by naming the fields returned and flagging the relevance caveat. It is sufficient for correct invocation, though a note on how many results/page default behave (already in schema) would round it out.

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 product_id, page, and limit are already fully documented; baseline 3 applies. The description implies the single-product anchor and supplies the Toman unit convention, but adds no parameter-level detail such as how page interacts with the loosely-related ordering.

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 ("List products Emalls shows as similar to one product") plus the shape of what comes back ("lowest price and shop count"). It is clearly distinct from em_search (find a product) and em_compare (verify relatedness), so an agent can route without opening a 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?

"Use it to offer alternatives or cheaper models next to a product from em_search" gives a concrete usage context, and "check with em_compare" names the follow-up tool when the list is loosely related. It lacks an explicit when-not-to-use case, but the caveat about loose relatedness effectively covers the main misuse risk.

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