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

Goes well beyond the annotations by disclosing side effects (emails the carrier, alerts the facility), the required authorization scope (appointments:write, Scheduler role or above), and the return value. The conflict rule and the note that the appointment's own slot doesn't count against availability add operational context the annotations cannot express.

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 its status precondition, and every clause carries information. The parenthetical about the appointment's own slot and the trailing authorization sentence make it slightly dense for a single paragraph, but nothing is wasted.

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 still states what is returned (the updated appointment). Authorization, side effects, failure mode, and the alternative tool are all covered, which is complete for a 3-parameter mutation.

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: startTime must be an unmodified value from get_availability, and doorId is optional with an auto-pick fallback. This is more than the schema restates.

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 ('Move a CONFIRMED appointment to a new start time and optional door') with an explicit precondition on status. It distinguishes itself from approve_appointment by routing PENDING requests elsewhere, so an agent can select it without opening the 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?

Explicit when-to-use and when-not-to-use: CONFIRMED goes here, PENDING goes to approve_appointment. It further constrains the valid input to a startTime that get_availability offered, and states the failure mode (conflict) if not.

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