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

Annotations already declare read-only, idempotent, open-world, and non-destructive behavior. The description adds non-obvious behavior: it reads several live calendars, may take a few seconds, and returns up to limit tours with card data and up to three open start times plus original-tour status. No contradiction.

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?

Three sentences, front-loaded with purpose, then invocation, then return and latency expectations. The limit/default detail repeats the schema, but every sentence contributes useful selection or expectation-setting information.

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 read-only tool with annotations, an output schema, and nested parameters, the description covers purpose, invocation, return shape, latency, and date-range cap. Remaining gaps are mostly sibling routing rather than missing call-critical information.

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 already documents date_end, travelers precedence, and party_size precedence, but overall coverage is 50%. The description adds meaning for bokun_id ('the tour the traveler wanted'), date/date-range scope, and party_size-or-travelers, but does not fully explain the nested travelers object or all constraints 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 ('Find tours similar to one TripWays tour') and scopes it to open start times on a date or date range for a group. It is clearly different in substance from check_availability or search_tours, though it does not name a sibling explicitly.

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?

Provides invocation guidance ('Pass the tour the traveler wanted ...'), which implies the use case, but it never says when to choose this over check_availability/search_tours or when not to use it. Alternatives and exclusions are left to inference.

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