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

With no annotations, the description carries the full burden. It does disclose two valuable traits: the operation is confirm-gated and the reason is client-visible. It omits whether cancellation is reversible, what happens to session attendees/notifications, and permission requirements, leaving meaningful behavioral gaps.

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?

Two tight sentences with the core action and the confirm-gate front-loaded; every clause earns its place with no filler.

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 mutation tool with no annotations and no output schema, the description covers the confirm-gate and reason visibility but omits side effects, reversibility, and permissions. Adequate but with clear gaps an agent would want filled.

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 33%, so the schema alone does not document 'reason' or 'sessionId'. The description partially compensates by clarifying that 'reason' is optional, short, and shown to the client. 'sessionId' remains undocumented and the confirm-gating is already explained in the schema.

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+resource ('Cancel a scheduled session'), which is clear and distinct in intent. However, it does not differentiate itself from nearby siblings such as cancel_gym_class_session or reschedule_session, so an agent must infer which cancellation path applies.

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 '(confirm-gated)' note implies a two-step usage pattern, which is useful context. But it never states when to use this instead of reschedule_session or cancel_gym_class_session, and gives no exclusions or prerequisites.

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