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

Annotations already signal readOnlyHint=true and destructiveHint=false, and the description adds meaningful behavioral detail beyond that: it renders a rate_comparison widget and returns specific valuations (cash rate, points rate, CPP, deal scores). This gives the agent a clear picture of what invoking the tool will do and what it will produce.

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 front-loaded with the core purpose, then gives usage context, parameter guidance, and return values in four focused sentences. Every sentence earns its place, and the examples are compact yet illustrative.

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?

The description covers purpose, when to use, how to source hotel_ids, the valid array size, required dates, and outputs. With full schema coverage and an output schema present, nothing essential is missing for an agent to select and invoke this tool correctly.

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 the baseline is 3. The description's parameter guidance—'Pass an array of one to five hotel_ids resolved from search_hotels'—mostly repeats what the schema already states. It adds no new semantic detail beyond the schema, so no higher score is warranted.

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 clear verb-resource pair: 'Compare cash vs points rates' and mentions rendering a side-by-side rate_comparison widget. It also names the specific outputs (cash rate, points rate, CPP valuation, deal scores), which clearly distinguishes it from sibling tools like get_multi_night_rates or diagnose_rates.

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 explicitly states when to use the tool: 'Use this whenever the user is making a cash-vs-points decision.' It gives concrete example phrasings and covers both single-hotel and multi-hotel scenarios. It does not explicitly list when not to use it or name alternative tools, so it stops short of a 5.

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