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

Goes well beyond the annotations by disclosing the diamond hold-then-spend lifecycle, the typical confirmation latency ('usually within a minute'), the refund on failure, and the reversibility path via move_booking/cancel_booking. Annotations only say it is a non-idempotent write with no destruction; the description supplies the actual economic and timing consequences.

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-loaded with the action and the cost, and every sentence carries information about cost, timing, or follow-up. Phrasing is occasionally awkward ('The answer's booking has its own label'), which costs a point but does not obscure the meaning.

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 3-parameter mutation with no output schema, the description covers cost, timing, failure refund, and follow-up tools adequately. It omits what happens when the person lacks diamonds or the hour is already taken by someone else, which an agent would benefit from knowing before calling.

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% and the start parameter's own description already states it must be passed exactly as my_bookings lists it, so the description's 'pass its start exactly as listed' largely repeats structured data. The instruction to name the hour by its label rather than a computed weekday adds intent but refers to a label that is not a parameter, so it is more confusing than clarifying.

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 ('spend ... diamonds on a one-to-one hour with Ben') with an explicit precondition tying it to my_bookings. An agent can distinguish it from book_intro_call, register_for_event, and the other booking siblings without opening any 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 a clear precondition (the hour must come from my_bookings) and explicitly routes post-booking actions to move_booking and cancel_booking. It does not, however, state when this tool should not be used versus other booking siblings such as book_intro_call.

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