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

Goes well beyond the readOnly/idempotent annotations by disclosing the pricing basis ('same calculation as the booking page: nightly or monthly basis'), the full success payload (apartments, total price, booking link, contact block), and the failure payload (reason, hint, contact block). This lets an agent handle both branches without guessing.

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-loads the purpose, then prerequisites, then return shape. Every sentence is functional, though the enumeration of contact-block fields (phone, email, address, hours, form link) is more granular than the agent strictly needs.

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 full burden of explaining return values, and it does so for both the success and empty-result cases. An agent has everything needed to call the tool and act on either outcome.

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 date formats, locale enum, and the persons default are already documented in the schema. The description reinforces the date-range and party-size concepts but adds no syntax or constraint detail beyond it, which is the expected baseline when the schema does the heavy lifting.

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 ('Lists the Guggach apartments that are available for a date range') and adds the value proposition ('returns the exact price for that stay'). There are no sibling tools to disambiguate from, and the scope is unambiguous.

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?

Gives an explicit prerequisite: if the user hasn't supplied check-in/check-out dates and party size, ask for them first. It also prescribes follow-up behavior when nothing is available ('pass these to the user and offer to check other dates'). No alternatives are named, but none exist in this toolset.

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