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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior. The description adds real value beyond that: it discloses the derived verdicts returned (lowest price, shortest duration, best rating with a 10+ review threshold, free cancellation flags) and how unresolvable ids surface in not_found.

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?

Front-loaded with the core action, then the returned attributes and derived picks, then the sibling routing. Every sentence earns its place with no filler.

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 an output schema present and full param coverage, the description supplies the extra semantics an agent needs: the derived 'best' logic and not_found behavior. Minor residual gap is ordering/pagination of results, which is low-impact for a max-4-item comparison.

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 schema already documents the 2-4 count, uniqueness, and the tripways.com/t/{id} form. The description repeats the count and id meaning without adding format or edge-case detail beyond the schema.

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 ('Compare 2 to 4 TripWays tours side by side by bokun_id') and enumerates the compared attributes. It also distinguishes itself from siblings by naming check_availability and get_price_quote for a different need.

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?

Clear positive guidance: use this to compare 2-4 tours by bokun_id, and route to check_availability/get_price_quote for group totals on a date. Lacks an explicit exclusion such as pointing to get_tour_details for a single tour, so not a full 5.

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