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

Beyond the readOnly/idempotent annotations, the description discloses conditional behavior: mock-sourced prices are placeholders, the online_booking flag changes the response to include per-room booking_options, and the tool never performs a write. It also specifies the fields inside each booking option so the agent knows what to hand to start_booking.

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 core capability is front-loaded in the first sentence and every subsequent clause carries behavioral information with no filler. The phrasing is terse and slightly telegraphic in places (quoted 'source' and 'online_booking' keys), but nothing is wasted.

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 availability/pricing tool with an output schema, the description covers the full agent-relevant flow: what comes back, the placeholder-price caveat, the expanded booking_options mode, and the handoff to start_booking or request_offer. Nothing needed to call it or act on its result is missing.

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 100%, so all seven parameters are already documented with types, ranges and enums, and the description adds no per-parameter detail beyond 'given dates and guests'. Its extra content concerns response fields (booking_options, total incl. city tax) and an output-only 'source' flag rather than input semantics. Baseline 3 applies 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?

The description states a concrete resource and return set: rooms for given dates and guests with a from-price per night in EUR plus the booking URL. That clearly separates it from plain listing tools like list_rooms or get_room, which supply ids rather than dated pricing. It stops short of naming those siblings explicitly, so differentiation is implied rather than stated.

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?

It gives explicit branching conditions — 'source' equals mock means prices are placeholders and the guest must be sent to booking_url; online_booking true means options should be passed to start_booking. It also closes the loop with 'Never books anything', routing the user to the site, start_booking, or request_offer, which is a clear when-not/alternative statement.

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