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

Annotations already declare readOnly/idempotent/non-destructive/closed-world, so the safety profile is covered. The description adds real behavioral value beyond that: it is deterministic rather than ML-ranked, capped at 5 results, restricted to in-stock bags, and each pick carries short reasons.

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 sentences, front-loaded with the capability and its constraints, followed by the usage trigger. No filler or restatement of the title.

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?

For a no-required-parameter recommendation tool with no output schema, the description adequately covers what comes back (up to 5 picks with short reasons) and the deterministic nature. It could note ordering semantics or what happens when no bag fits, but the essential call-time information is present.

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 all six parameters (market, airline, budget_eur, travellers, trip_nights, checked_bag_ok) are already documented, including the market default and checked_bag_ok default. The description hints at how inputs feed the ranking but adds no format or syntax detail beyond the schema, so the baseline 3 applies.

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+resource ('shortlist of up to 5 in-stock bags for a trip') and names the exact ranking inputs (size, cabin fit, budget, popularity, discounts). This clearly distinguishes it from siblings like search_products or check_airline_fit, which are narrower or raw-listing tools.

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 an explicit trigger phrase ('Use when the user asks what suitcase should I take/buy for …'), which is strong context. It stops short of stating when NOT to use it, e.g. that search_products or check_airline_fit should be preferred for browsing or single-airline verification.

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