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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely useful behavior: the empty-city enumeration mode and the fact that departures are only returned when dates are supplied. It does not cover result ordering, pagination or the empty-result case.

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, zero filler, and the primary capability plus return payload are front-loaded before the edge-case guidance. Every sentence carries information an agent can act on.

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 correctly takes on the job of describing the return payload (ids, names, descriptions, duration, meeting spot, price, departures). It is nearly complete for a 4-param search tool; only pagination and no-results behavior are unaddressed.

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 city examples, the 14-day end_date window, the 1-50 party size range and that start_date requires city. The description's parameter statements (date range, party size, no-city listing) largely restate that, 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?

The description opens with a specific verb and resource ("Find American Ghost Walks ghost and history walking tours") and states the filtering axes (city, date range, party size). It hints at the sibling relationship by saying to reuse a tour id "with the other tools," but never names get_availability, get_tour_details or get_booking_link, so the agent still has to infer which sibling follows.

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 usage context is given: call with a city to filter, call with no city to enumerate everything, and add dates/party size to surface open departures. What's missing is an explicit contrast — nothing says when to skip this tool and go straight to get_availability or get_tour_details instead.

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