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

Annotations already declare readOnly=false, idempotent=true and destructive=false, so the description does not need to restate safety. It usefully adds side-effect context the annotations lack: the arrival starts a dwell-time clock that ends only when the appointment is marked COMPLETED. It does not mention permission requirements or behavior when the appointment is already arrived, which keeps this short of a 5.

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?

Three sentences, each doing distinct work: definition, lifecycle/side effect plus undo, and sibling disambiguation. Front-loaded with the core action and zero filler.

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 two-parameter mutation tool with no output schema, the description covers the action, its side effect on dwell time, the reversal path, and the nearest sibling. What is missing is edge-case behavior (e.g. re-arriving an already-arrived appointment) and any authorization context.

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 description coverage is only 50% (appointmentId is undocumented), so the description carries extra burden. It explains that arrived: false undoes a mistaken arrival, adding intent and rationale beyond the schema's terse 'false clears the arrival', though the appointmentId parameter remains unexplained.

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 ('Record that a truck has physically arrived at the dock') and grounds it with a concrete example utterance. It also explicitly differentiates itself from the sibling check_in_appointment, so an agent can select correctly without opening either 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 the trigger condition (physical arrival at dock), the undo path (arrived: false), and an explicit exclusion: 'Not the same as check_in_appointment, which records the driver's own on-track or running-late update before arrival.' When-to-use, when-not-to-use, and the alternative are all present.

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