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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered without prose. The description adds real value beyond them by disclosing the return granularity — a per-night available/not-available status — which is important since no output schema exists. It still doesn't say whether results reflect live inventory or cached data, which limits it below 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?

Two short sentences with zero redundancy: the first states the operation and scope, the second states the return value. Front-loaded and appropriately sized for a simple three-parameter read.

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 read-only, three-parameter tool with full schema coverage and no output schema, the description supplies both the query semantics and the response shape, which is what an agent needs to call and interpret it. The remaining gap is boundary context — how it differs from the other availability tools in this large sibling set.

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 three parameters (roomId, checkIn, checkOut) are already documented with format details, establishing the baseline of 3. The description does not add anything the schema lacks, such as whether checkOut night is included in the per-night list or how check-in/check-out ordering is validated.

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 gives a specific verb ('Check'), a specific resource ('a specific room'), and a precise scope ('each night in a date range'), plus the return shape (available/not available per night). That is far more specific than a generic 'get availability'. It does not name the related siblings it must be distinguished from (checkStayAvailability, getAvailabilityByMonth, hasAvailabilityInWindow, findNearestAvailability), so an agent has to infer the boundary itself.

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 per-night granularity and single-room scope imply the use case — you call it when you need night-by-night availability for one room rather than a whole-stay or month-level answer. However, there is no explicit statement of when to use this versus the several sibling availability tools, and no prerequisites (e.g. whether roomId must be a valid stay room).

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