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 earns credit by disclosing the shape of the generated result (day grouping, visiting order, approximate timetable, meal stops), which matters because there is no output schema; it stops short of covering empty-area behavior, determinism, or cost/latency.

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?

A single front-loaded sentence that specifies the resource, the output structure, and the inclusions with no filler. Every clause carries information an agent can use.

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 all five parameters optional and no output schema, the description usefully explains what comes back, which is the main gap it needed to fill. It is close to complete, lacking only what happens with an unrecognized or empty area and whether the timetable is fixed or variable.

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% and each parameter is documented with defaults, bounds, and enum fallback notes, so the schema does the heavy lifting. The description only adds the notion of 'a region' mapping to the area parameter and nothing about per_day, num_days, day_start, or locale behavior, so 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 ('Build a day-by-day sightseeing itinerary for a region') plus the concrete output shape: spots grouped by day, in visiting order, with approximate timetable and meal stops. That level of detail makes it clearly distinct from lookup siblings like search_places and find_nearby_places, though no sibling is named 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?

Usage is only implied: the description frames the tool as producing a multi-day plan, which suggests it is the right choice when the user wants an itinerary rather than individual places. There is no explicit 'use this when...' or 'use X instead for single-place lookups' statement, and no prerequisites are stated.

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