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

Annotations already cover the safety profile (readOnly, idempotent, non-destructive, openWorld), and the description adds real behavioral constraints beyond them: the 14-day maximum window and the fact that returned times are offers rather than reservations. It does not disclose result shape or rate limits, so it falls 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 sentences, zero filler, with the format constraint and the example placed immediately after the purpose. The opening fragment is slightly telegraphic but not wasteful.

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?

No output schema exists, so the description should say more about what comes back — a list of slots, whether times are returned in the requested offset, and how business_id and service_id relate. The 14-day and offers-not-holds details are genuinely useful, but the return-value gap leaves it only partially complete.

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 0% with four required parameters, so the description must compensate. It documents start and end thoroughly (ISO 8601 with UTC offset, concrete example, 14-day span), but leaves business_id and service_id entirely unexplained.

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 resource and outcome ('Open times for a service'), which an agent can distinguish from book_appointment and list_services in the sibling set. It is a noun phrase rather than a verb+resource construction, but the intent 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?

Usage is only implied: 'Times are offers, not holds' hints that a follow-up booking (book_appointment) is required, but no alternative tool is named and no explicit when/when-not condition is given.

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