compare_offers

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

Annotations already declare readOnly/idempotent/non-destructive/openWorld, so the safety profile is covered. The description adds genuinely useful context beyond that: ranking is by item price only, and equivalence and landed totals are explicitly not verified, which materially affects how an agent should interpret results. It does not contradict the readOnlyHint (refresh here reads as re-fetch).

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 tight sentences with no filler, front-loading the core action before the caveat. Every clause earns its place.

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, the description reasonably frames the result (ranked offers by item price) and flags the key limitation. However, for a 3-required-parameter tool with zero schema coverage, it omits the country parameter's role and the ranking tie-breaking/limit behavior, leaving gaps an agent must guess at.

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 0%, so the description must carry parameter meaning. It conveys the gist of variant_ids and currency, but says nothing about the required country parameter (ISO-2), the 2-10 variant limit, uniqueness, or the GID format expected. Only partial compensation for the coverage gap.

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 specific verbs (refresh, rank) and a specific resource (variant offers), with the scoping constraint of a single currency. It is clearly distinguishable from siblings like search_products or get_product, though it does not explicitly name a sibling it replaces.

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 implies a comparison use case but never states when to choose this over siblings such as compare_shipping_plans or get_product, nor any prerequisites. No exclusions or alternatives are offered, leaving routing to inference.

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