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

The description adds valuable behavioral context beyond the annotations: the current reservation is auto-fetched, no reservation number is needed, the action is two-phase and requires confirm_action, and a LIBRARY-logged-in session is needed. This meaningfully clarifies the non-readOnly, non-idempotent prepare flow. It does not describe failure/error behavior, but it is reasonably transparent for a prepare tool.

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 short sentences, each with distinct value: the core action, the automatic reservation lookup, and the confirm_action/auth requirement. The description is front-loaded and contains 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?

The description covers the core workflow and auth precondition, but there is no output schema and the prepare-to-confirm handoff is left implicit. An agent is not told what this tool returns or how that result should be passed to confirm_action. It also does not state what happens if there is no current reservation to cancel.

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?

The schema already covers the sole parameter at 100%, so the baseline is 3. However, the description says 'mcp_session_id 필요(LIBRARY 로그인)' while the schema explicitly marks mcp_session_id as optional with a transport-bound session fallback. This is misleading: an agent may treat an optional parameter as required based on the prose.

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 states a specific verb ('반납합니다' - return/cancel) and a specific resource ('숭실대학교 중앙도서관 현재 예약된 좌석'). It also clarifies that the current reservation is looked up automatically, which distinguishes this cancellation path from sibling reserve/swap/waitlist 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?

It gives clear context: use when the user wants to return or cancel their currently reserved library seat. It also explicitly states that this tool alone does not execute the cancellation and that confirm_action must be called, plus notes the LIBRARY login requirement. However, it does not explicitly name alternative tools or state when not to use it.

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