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

Even with annotations declaring readOnlyHint, the description adds valuable behavioral context: ordering (most recent first), inclusion of cancelled appointments (shown via status field), pagination with default limit (20), and the authorization requirement. These details go beyond what the annotations alone convey.

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?

The description is four concise sentences, each providing essential information: main purpose with fields, pagination, cancelled appointment behavior, and authorization. It is front-loaded with the primary purpose and contains no 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?

With no output schema, the description adequately covers return fields, ordering, pagination, cancellation behavior, and authorization requirements. For a simple read-only list tool, this is complete and leaves no major gaps for an agent to infer.

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?

The input schema provides no descriptions for limit and offset (0% coverage). The description fully compensates by explaining 'limit (default 20) and offset for pagination', giving both purpose and default value for each parameter.

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?

The description clearly states the resource ('the user's past appointments'), includes key fields (booking_id, date, time, status), and specifies ordering ('most recent first'). It distinguishes itself from the sibling tool 'list_current_bookings' by focusing on past appointments, and also notes that cancelled appointments are included.

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 description implies usage context by explicitly saying 'past appointments' and mentioning pagination, but it does not explicitly name an alternative or state when not to use it. The distinction from 'list_current_bookings' is clear via the word 'past', providing clear context without formal exclusions.

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