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

With no annotations, the description carries the safety context well: it states partial-update semantics ('Only what you give changes'), that no days means all open days, that active=true re-enables a disabled link, and that some actions are refused from an agent's own turn inside Caddie. It also warns that a new title changes the URL unless the address was set by hand and that the old URL still works, which is valuable mutation side-effect disclosure.

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 dense and front-loads the core operation before listing affected fields and behaviors. It earns its place overall for a 24-parameter update tool, though the long semicolon-separated sentence is harder to scan than a more structured presentation would be.

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?

Given the rich input schema, the description covers the essential gaps: it identifies the operation, the lookup sibling, partial-update behavior, notable side effects, and agent-turn restrictions. It does not need to explain return values because no output schema exists, and the schema carries the detailed parameter documentation.

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 high at 88%, so the schema already documents most parameters in detail. The description adds some useful meaning, especially for title URL changes and active re-enabling, but much of its parameter coverage is just naming fields rather than explaining semantics beyond what the schema provides.

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 opens with a specific verb and resource: 'Change one of the user's booking links.' It clearly identifies this as an update operation on an existing link and points to list_booking_links for locating it, making it readily distinguishable from create/delete/disable siblings.

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?

It implies the tool is for modifying an existing link and names list_booking_links as the lookup mechanism. However, it does not explicitly say when to use this versus create_booking_link, delete_booking_link, or disable_booking_link, leaving the agent to infer the boundary from the tool name and the mention of active=true re-enabling.

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