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

Despite minimal annotations, the description discloses important side effects: the calendar event is updated, the provider notifies attendees, and payment carries over. It also documents a specific failure mode (409 change_too_late), going well beyond what the annotation flags provide.

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 description is three tight sentences, each carrying a necessary fact: the core operation, the prerequisite workflow, and the side effects/constraints. 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 mutating tool with no output schema, the description covers prerequisites, side effects, carryover behavior, and the late-change failure condition. The agent has enough context to invoke the tool correctly and know what to expect.

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 only gives generic length constraints and a date-time format, so the description adds meaning by identifying `id` as the booking identifier and `start` as a value sourced from get_available_slots. The `token` parameter's purpose is implied through the workflow reference but not explicitly explained.

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 action ('Moves a confirmed booking to `start`'), the resource ('confirmed booking'), and key scope ('with the same hosts'). It also identifies the persona (invitee) and clearly distinguishes the operation from cancelling or creating a 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?

It explicitly directs the agent to get valid times from get_available_slots using the booking ID and token, and warns that rescheduling is not possible after `changeableUntil`. It does not explicitly contrast with cancel/rebook alternatives, but the prerequisites and blocking condition are clear.

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