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

Annotations already declare readOnlyHint, idempotentHint, and openWorldHint=false, so the low bar is met. The description adds meaningful context beyond that: 'historical snapshots, not live availability,' which is a genuine behavioral trait an agent must know (prices may be stale, not bookable). Return contents are also summarized.

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 tight sentences, front-loaded with the core action, then return shape, then the critical caveat. Every sentence earns its place with no redundancy.

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?

An output schema exists so return values need not be elaborated, but with 16 parameters and only 38% description coverage, the definition leaves a large filter surface under-explained. The mode guidance is present, but the many filter parameters lack any narrative meaning.

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?

At 38% schema description coverage the description should compensate, but it only addresses the date-vs-nights mode mapping. It says nothing about the 16 parameters' filters (sources, max_nightly_usd, required_signals, min_rating_fraction, freshness_days), leaving most of the surface documented only in the schema (or not at all).

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?

Specific verb (Search) plus resource (stored lodging price observations) and scope (a city). It clearly distinguishes a raw price-search from aggregation siblings implicitly via 'observations,' but never names compare_lodging_months or compare_city_costs, leaving the agent to infer which sibling handles comparison.

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?

It explains the two calling modes (exact dates via checkin/checkout vs stay length via nights), which is useful usage guidance. However, it gives no when-not-to-use or explicit routing to the many comparison siblings, so an agent still has to guess when search_lodging vs compare_lodging_months applies.

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