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

Beyond the readOnly/idempotent annotations, it discloses default window (7 days), maximum window (14), that the searched window is echoed as 'window', a 50-result cap, pagination via 'more'/'next_from', and the critical caveat that returned times are not reserved. These are exactly the behavioral traits an agent cannot infer from annotations.

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?

One dense paragraph, front-loaded with purpose then input rules then return shape; almost every clause carries information an agent needs. It is long and slightly wall-of-text, but there is no filler or repetition of annotations.

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 fully covers the return contract (count cap, exact vs. local time, pagination fields, the echoed window) plus the time-zone and window defaults. Nothing needed to call or interpret the tool 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 already 100%, so the baseline is 3, but the description adds real meaning: date vs. offset date-time formats with an example, that a 'to' date includes the whole day, and that the returned start must be passed unchanged to request_booking. Only staff_id is left entirely to the schema.

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 precise verb and resource ('open start times for one 904 Digital Media service, read from the live calendar') and situates it against both siblings: list_services supplies the id, request_booking consumes the returned start. An agent can distinguish it from read-only service listing and from booking without opening a schema.

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 clear context for use: call it to see open start times before requesting a booking, and it explicitly notes times are not held and request_booking re-checks. It stops short of an explicit when-not statement or naming a competing availability alternative, but the workflow routing is unambiguous.

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