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

Annotations declare readOnlyHint, idempotentHint, destructiveHint=false, but the description adds substantial behavioral context beyond them: the URL is short-lived, nothing is reserved, a popular slot can still be lost, and the page itself collects contact details. This is exactly the kind of non-inferable behavior an agent needs.

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?

Front-loaded with the core 'this does not book' clarification, then the mechanics and the guest-handling caveat. Every sentence earns its place, though it runs slightly long for a three-parameter tool.

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 correctly explains the return value (the url) and the tool's non-mutating nature. Combined with annotations covering safety, an agent has everything needed to call it and instruct the guest 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 100%, so the baseline is 3. The description reinforces the slotToken's signed/expiring nature and the venue slug's origin, but these are already documented in the schema; it adds little parameter-specific meaning beyond what structured fields provide.

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: it converts a time from find_appointment_times into a guest-tappable booking link. It explicitly negates the sibling action with 'This does NOT book anything', so an agent can distinguish it from book_table without opening either schema.

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?

Names the prerequisite tool (find_appointment_times) as the source of the time, states the negative case (it does not book), and gives operational guidance ('Give the guest the url', 'Never ask the guest for their contact details'). Clearly tells the agent when and how to use it.

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