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

Beyond the read-only/idempotent annotations, the description explains important behavioral traits: results are based on observed sampled check-in dates, not monthly averages; it returns each month's distribution, a like-for-like subset of properties present in every month, and a cheapest month derived only from that subset. These details materially affect interpretation of the output.

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?

The description is three focused sentences: purpose first, then return composition, then the key sampling caveat. Every sentence adds useful information and there is no redundant 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?

For a six-parameter comparison tool with an output schema and read-only annotations, the description covers the main purpose, output composition, and the critical 'sampled check-in date, not monthly average' caveat. It leaves out explicit sibling routing and does not discuss freshness_days, but the structured schema and output schema carry much of the remaining detail.

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 67%, with descriptions present for city, months, nights, and freshness_days. The description adds useful meaning around 'single stay length and occupancy' and clarifies that months are sampled check-in dates, but it does not compensate for the undocumented rooms/adults parameters or explain freshness_days.

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 states a specific verb and resource: compare observed nightly lodging rates for one city across check-in months, with a single stay length and occupancy. That scope is clearly distinct from a generic lodging search or city-cost comparison, so an agent can identify the tool's role without opening the schema.

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?

The description implies when this tool is appropriate: cross-month comparison of lodging rates using collected check-in months. However, it does not explicitly say when to use it instead of search_lodging, nor does it name any alternative or exclusion condition.

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