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

Annotations already declare read-only, idempotent, non-destructive, so the safety profile is covered; the description adds genuinely new behavior — result ordering by start and the half-open range semantics. It does not disclose what happens when start/end are left null (presumably unbounded) or how results paginate.

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?

A single dense sentence with zero filler: the [read] tag flags safety, the interval semantics and ordering come first, and the optional customer filter trails it. Every clause earns its place.

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 six-parameter, no-output-schema tool, the description leaves two real gaps: the null-default behavior of start/end (does omitting them mean unbounded?) and the existence default of pagination (per_page=500, page=1), which matters a lot for how an agent consumes the list. Otherwise it is adequate.

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 0%, so the description has to carry parameter meaning — and it does for four of six: it clarifies that start/end are ISO 8601 and that the interval is half-open, and that customer_id and customer_uuid are two ways to address the same optional filter. It says nothing about page or per_page (defaults 1 / 500), leaving a third of the parameters undocumented in both places.

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 ('List appointments') plus the scope that defines it: a half-open ISO 8601 interval [start, end), sorted by start, with optional single-customer filtering. An agent can distinguish it from create_appointment and from the many other list_* siblings 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?

The scoping sentence gives clear context for when this is the right call (bounded date range, optionally narrowed to one customer). It does not name an explicit alternative or state when not to use it, but for a plain list endpoint against an obvious create_appointment sibling that is a minor omission.

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