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

readOnlyHint=true already covers the safety profile, but the description reinforces it with 'nothing is booked or held,' which is meaningful disambiguation against the write siblings. It adds no detail on auth, rate limits, or error cases (e.g., unavailable dates), 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?

Three short clauses with zero padding: what it does, what it is not, and the underlying endpoint. The atomic constraint ('nothing is booked or held') is front-loaded where an agent will see it.

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 usefully lists the return breakdown (base rate, cleaning fee, taxes, discounts), and all parameters are schema-documented. Minor gaps remain on failure modes and whether the response includes per-night detail.

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 six parameters (including markup and reservationCouponId) are documented in the schema. The description adds no parameter-level guidance beyond naming the returned cost components, 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 ('Calculate what a stay at a listing would cost') and enumerates the returned components. It also distinguishes itself from the booking siblings by declaring 'A calculation only: nothing is booked or held.'

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?

Clearly frames this as a quote-only operation, implying that booking requires a different tool (e.g., hostaway_create_reservation). It lacks an explicit 'use X instead to book' routing sentence, but the when/when-not boundary is unambiguous.

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