Compare products side by side

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

Annotations already declare readOnly, idempotent, non-destructive, and openWorld behavior. The description adds important output semantics beyond annotations: differing specs are listed per product id, missing means no site value, `same` counts shared specs, and prices are in Toman. It does not cover operational details like rate limits or error behavior, but with annotations present this is strong added context.

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 front-loaded with what it compares, then immediately explains output fields and routing. Four sentences, each carrying distinct information about scope, trigger, return shape, and next steps, with no redundant padding.

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?

Given a single-parameter tool with no output schema, the description supplies the missing return-shape details (`specs`, `same`, missing-value meaning, Toman pricing), input sourcing, and a follow-up tool. Annotations already cover safety, so no critical behavior is left unexplained.

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 single parameter is already documented as an array of 2 to 5 Emalls product ids from em_search or em_similar. The description repeats that sourcing and count constraint but adds no new parameter-level syntax or format information. Baseline 3 is appropriate when the schema carries parameter semantics.

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 states a specific verb and resource: compare 2-5 Emalls products across prices, rating, and only differing specs. It also distinguishes itself from siblings by routing id lookup to em_search/em_similar and shop lookup to em_offers, so an agent can identify its niche without opening other schemas.

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?

It gives an explicit trigger ('when the user is choosing between models') with a concrete example, and names the alternatives for obtaining ids and for shops of the winner. This is clear when-to-use plus alternative routing, leaving little inference required.

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