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

Annotations already cover readOnly/idempotent/non-destructive/openWorld, so the bar is lower, and the description adds real value: a hard 120-day window limit and an explicit statement of what is NOT returned (stay totals, deferred to get_quote). It does not discuss pagination or result size, so it stops short of a 5.

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?

Four tight sentences, front-loaded with the core action, then mode behavior, then constraints, then the boundary with get_quote. Every sentence carries distinct information with no repetition of the name or title.

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 an 8-parameter read tool with no output schema, the description covers the essential contract: inputs' date format and window limit, the two query modes, and the exact return surface. Gaps are minor – the individual party-size parameters are only collectively implied.

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 50%, so the description must compensate, and it does for the two decisive parameters: it explains that destinationId alone yields the site-wide calendar while accommodationTypeId narrows to one unit type with pricing. It also notes the 120-day date limit and that party size ('party-adjusted price') affects results, though numAdults/numChildren/numInfants remain semantically undocumented.

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 ('Check which dates are free') and immediately disambiguates the two operating modes: destinationId alone returns the site-wide calendar, accommodationTypeId returns per-date availability plus party-adjusted price. An agent can distinguish it from get_quote and search_stays without opening a 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?

Explicitly says when to use each mode (destinationId alone vs adding accommodationTypeId) and routes the agent to the correct alternative for stay totals: 'the full stay total comes from get_quote.' No condition is left to inference.

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