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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the description does not need to restate safety. It adds meaningful context beyond annotations: the default time window, the notion of 'inside a coach's hours,' and the eligibility rule that only accepted students can book. It stops short of describing output shape or whether booked slots are excluded, but the added behavioral context is valuable.

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 two short sentences with zero filler. The core resource and default window are front-loaded, and the eligibility/precondition guidance is packed into a compact second sentence. Every word contributes to the agent's understanding.

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 simple read-only listing tool with two parameters and a full schema, the description covers the essential purpose and a key precondition. However, there is no output schema, and the description does not clarify the return format (e.g., date-time representation, granularity) or whether the list only includes unbooked slots. These gaps leave some ambiguity for an agent trying to interpret the result.

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 both parameters are well-described in the schema: handle includes an example, and days includes its default and range. The description mentions 'default 14' but this duplicates the schema text. No additional parameter-level meaning is provided beyond the schema, so the baseline score of 3 is appropriate.

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 identifies the resource as a coach's free time starts within the next days and defaults to 14. It distinguishes itself from booking/requesting siblings by noting that only accepted students can book and that request_coach is a prerequisite. However, it lacks an explicit imperative verb like 'list' or 'get,' so the action is implied rather than stated directly.

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 gives useful context: this tool surfaces free starts inside a coach's hours over a configurable future window, with a default of 14 days. It also signals the prerequisite flow ('request_coach first') and the booking restriction. It does not explicitly rule out alternatives like find_coaches or find_clubs, but the context is clear enough for an agent to select this tool when a specific coach's availability is needed.

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