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

Adds a side effect the annotations do not cover: Splose may notify the patient of the change per practice settings — a real-world consequence an agent should weigh before calling. Idempotency is restated from idempotentHint=true (no extra credit), and destructiveHint=true is left unexplained: the description never says what is lost or whether a reschedule is reversible.

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 tight sentences, front-loaded with the WRITE marker and the scope constraint, closing with the underlying endpoint. No filler, and the operationally important instruction (partial fields) arrives before the caveat.

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?

Annotations already carry idempotency and destructiveness, and there is no output schema to explain, so the remaining need is modest and mostly met. The gaps are what destructiveHint=true means in practice and what the call returns (updated appointment vs. no content), neither of which the description addresses.

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%, so the baseline is 3, but the description adds the partial-update contract ('only the fields to change'), which the schema does not state and which changes how the 8 properties should be populated. Field-level types/formats (UTC timestamps, integer ids) are correctly left to the schema.

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?

Opens with an explicit 'WRITE' verb tag, then names the resource and the exact mutable fields (time, service, location, practitioner, case, patient) scoped to ONE existing appointment. The 'ONE existing' phrasing plus the enumerated reschedule fields cleanly separates it from splose_create_appointment and splose_cancel_appointment without needing their schemas.

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?

'Send only the fields to change' is a concrete invocation rule that materially shapes the call. It stops short of naming alternatives or exclusion cases (e.g. use splose_cancel_appointment to cancel rather than blanking fields), so it is clear context rather than full when/when-not guidance.

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