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

Annotations cover idempotency and non-destructiveness, so the burden is lower. The description adds valuable behavioral context about its legacy/compatibility-only nature and a critical chat-safety guardrail about not asking for SMS codes. Side effects are not detailed, but annotations already establish the safety profile.

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 sentences with no filler. The core purpose is front-loaded, followed by critical prohibitions and an alternative route. Every sentence earns its place.

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 an output schema present, one parameter, and strong annotations, the description supplies purpose, exclusions, and alternative routing. It could more explicitly define what counts as an 'explicitly initiated legacy profile-link session,' but that is a minor gap for a compatibility-only endpoint.

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 0%, so the description must compensate. It refers to an 'explicitly initiated legacy profile-link session' and the parameter is named linking_session_id, but the description never explicitly defines the parameter, its origin, or how to obtain it. The mapping is inferable but not stated.

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 specific role: 'compatibility-only completion for an explicitly initiated legacy profile-link session.' It distinguishes this from new-booking and existing-appointment flows, preventing confusion with sibling booking-management tools.

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?

Explicit when-not-to-use guidance is given: 'Never call it as part of a new booking' and 'never ask for an SMS code in chat.' It also names the alternative path for existing appointments: 'starts Connect through the corresponding booking-management tool.'

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