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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, open-world), and the description layers on substantial extra behavior: beta instability warning, $0.05 per-request pricing, a 10 req/min rate limit with the resulting 429 response, the 1,000-hotel aggregation cap, and the future-check-in-dates-only constraint. This is exactly the kind of operational context annotations cannot express.

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?

Front-loaded and well-headed, but the content is padded: city-level aggregation, per-night pricing, and future-dates-only are each stated in both 'What You Get' and 'Key Features', so a meaningful share of the text is redundant rather than earning its place.

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 carries the return-value burden and does so well: it specifies averaged per-night prices, one entry per calendar day, aggregation across up to 1,000 hotels, and future-only dates. Combined with cost and rate-limit disclosure, an agent has everything needed to call and interpret it.

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%, so all four parameters (including defaults and format) are already documented in the schema. The description's 'Parameters' section largely restates that, adding only the 'only future check-in dates are queried' nuance, 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?

States a specific verb and resource ('Retrieve aggregated historical price index data for all hotels in a specific city') and explicitly scopes it as city-level aggregation 'not per hotel', which distinguishes it from the sibling getPriceIndexHotels without requiring 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 'When to Use' section gives four concrete scenarios (city-level analysis, market research, destination pricing, dashboards), which is clear positive context. However, it never names the obvious alternative getPriceIndexHotels or states when this tool should NOT be used instead, so it stops short of full when/when-not guidance.

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