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

Even though readOnlyHint is already true, the description adds useful behavioral context that annotations do not provide: the enabled:false state for disabled plans, exclusion of a booking's own slot during rescheduling, and server-side clamping of over-long date ranges. No contradiction with 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?

Four sentences, each carrying distinct value: core operation, edge-case return, rescheduling workflow, and range limit behavior. The most important use-case instruction is clearly placed, and there is no filler or repetition of schema details.

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 tool with a rich schema and output schema available, the description covers the query behavior, conditional logic, critical rescheduling prerequisite, and server-side adjustments. It gives an agent everything needed to call it correctly in the main workflow.

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?

The schema already describes all three parameters well, including ISO datetime semantics and exclusivity of toDate. The description adds extra meaning by explaining bookingId's exclusion behavior and the server-side range clamp, which helps an agent understand edge cases without opening additional documentation.

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 specific verb and resource: 'Read the current team's bookable time slots in a date range.' It also explains the calculation rule ('weekly booking rules minus what is already taken'), which makes the tool's purpose concrete and distinguishable from siblings like list_bookings or reschedule_booking.

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?

The description explicitly instructs agents to 'always call this before reschedule_booking' and gives the reason: a start time outside the available slots is rejected. It also provides conditional guidance for when to pass bookingId and when to omit it, which is actionable and clear.

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