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

Annotations already cover read-only and non-destructive, so the description's main contribution is the explicit note that the API documents no paging for this list — a genuine behavioral constraint an agent would otherwise assume away. It does not describe result size, sorting, or the shape of returned contracts.

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 short sentences, front-loaded with the resource definition, then the search surface, then the paging caveat. Nothing redundant or padded.

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 single-parameter read-only list tool with no output schema, the description covers purpose, filtering, and the notable absence of paging. Missing only what the returned contract objects contain and whether search is a partial or exact match.

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 100% and the single parameter already enumerates product name, variant name, order number and customer name. The description restates that same list verbatim, adding no format hints, matching behavior, or empty-string handling beyond 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?

States a specific verb and resource ('List the recurring booking subscription contracts') and clarifies the domain with the parenthetical about repeat-appointment subscribers, which separates it from appointo_list_bookings and appointo_list_appointments. It does not explicitly name or contrast those siblings, so it stops short of a 5.

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 search-fields sentence implies how to narrow results, but there is no statement of when to choose this tool over the booking/appointment list siblings, nor any exclusion or prerequisite. Usage is inferable rather than prescribed.

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