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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It mentions the side effect of holding a slot, the single-use nature of the pay link, the server-set price restriction, and that payment/consent stays with the customer. This covers key behaviors, but does not explicitly state what happens if the slot is already taken or whether the hold expires. Still, the instruction to call check_availability mitigates some gaps, making this a solid 4.

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 three sentences, front-loaded with the primary action, and each sentence adds value: the core behavior, the prerequisite, and a critical constraint. There is no redundant phrasing or filler. It is well-structured and easy to parse.

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 7-parameter creation tool with no output schema, the description covers the essential workflow: check availability, collect customer info, and call this tool. It explains the output (pay link) and key constraints (server-set price, payment/consent). It does not describe the response structure or error handling, but given the explicit prerequisites and the simplicity of the task, it is sufficiently complete for an agent to invoke 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?

Schema coverage is only 43% (3 of 7 parameters have descriptions). The description adds context for name, phone, and email by instructing to collect them, but it does not explain plan_code or session_type at all. It does mention that the price is server-set, which indirectly relates to plan_code, but it doesn't clarify that plan_code determines the price or the meaning of the enum values. Thus, it partially compensates for the low coverage but leaves two parameters unexplained.

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 tool's action: “Hold a specific slot and return a single-use pay link.” This is specific enough to distinguish it from siblings like check_availability (which checks) and get_booking_status (which retrieves status). It also explicitly names the resource (slot) and the output (pay link), leaving no ambiguity about the tool's core purpose.

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 provides explicit usage instructions: “Call check_availability first and use one of its times” and “Collect the customer's name, phone, and email first.” This tells the agent exactly when to use this tool (after availability check) and what prerequisites must be met. It also implies that the tool is not for payment handling, which helps avoid misuse.

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