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

Annotations already declare read-only, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new behavioral facts beyond them: prices are integer cents matching the product page, and 'unconfirmed availability is not in stock' tells the agent how to interpret availability output. It omits the agent-profile/meta requirement and any partial-match failure behavior.

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?

Four short sentences, front-loaded with the purpose and key, then pricing, matching mechanics, and availability. No filler, though the availability sentence is terse enough to be slightly ambiguous in placement.

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?

The tool has nested objects, two-level required fields, and no output schema, so the description should do more. It covers pricing units and availability interpretation well, but never mentions the required agent profile envelope or the country context field, leaving an agent to infer those from an undescribed schema.

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 explains the semantics of 'selected' (narrows matches) and 'preferences' (relaxed last to first), including a non-obvious fallback order, but leaves catalog.context.address_country and the required meta.ucp-agent.profile undocumented.

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 and identifies the key (catalog ID) plus that variants are covered. It does not distinguish itself from siblings like lookup_catalog or search_catalog, so an agent cannot tell from the description alone which entry point to use for discovery vs. direct fetch.

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?

Usage is implied by 'by its catalog ID' and the note that 'selected options narrow matches; preferences are relaxed from last to first', which hints at the fetch-with-filters case. However, there is no explicit when-to-use/when-not, no statement that an ID must first be obtained via search_catalog or lookup_catalog, and no guidance on resolving unmatched preferences.

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