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

Annotations already cover read-only/idempotent/non-destructive, so the bar is lower. The description adds genuine context beyond them: the 14-day window, the per-day aggregation, and the privacy scoping ('no client or stylist names'), which tells the agent what is deliberately omitted.

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 usage trigger, then the return shape, then the boundary. Every sentence earns its place with no redundancy.

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?

An output schema exists, so return values needn't be spelled out, and the description nonetheless summarizes the aggregation and the 14-day cap. Combined with full annotation coverage, an agent has enough to invoke it correctly.

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?

Only one parameter (salonId) and schema description coverage is 100%, so the schema already documents the id format and constraint. The description adds no parameter-level meaning, making the baseline 3 correct.

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+resource ('free appointment slots', 'next opening') and clearly distinguishes itself from siblings like get_appointment and list_appointments by describing what it returns per day. An agent can tell this is an availability lookup, not an appointment retrieval.

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?

Explicitly says when to use it ('when someone asks when their hair salon has free appointment slots or the next opening') and adds a boundary ('Not for making a booking'). No sibling alternative is named for the booking case, but the exclusion is clear.

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