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

Annotations already declare destructiveHint=true and idempotentHint=true; the description adds the consequence of that destructiveness — unsaved changes are dropped — which tells the agent what it loses before calling. It does not cover behavior on an already-closed or unknown session_id (error vs no-op), which would be the last needed detail.

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 short sentences, front-loaded with the action and its data-loss consequence before the sibling comparison. Nothing redundant.

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 one-parameter, no-output-schema tool with annotations covering safety and idempotency, this is nearly complete: the agent knows what it closes, what is lost, and where to go to save instead. Only edge-case behavior on invalid sessions is unstated.

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?

Only one parameter and schema coverage is 100%, with the schema itself explaining that session_id comes from studio_open_page. The description adds no additional meaning about the parameter, so baseline 3 applies.

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 ('close the session') and immediately qualifies the scope ('without saving: its changes are dropped'). It also names the sibling studio_save so the agent can distinguish the two without opening a 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?

Implies the selection rule clearly: use this to abandon changes, use studio_save to persist them (since saving also closes the session). No explicit exclusion cases such as 'do not use on a session with required unsaved state', but the alternative is named and characterized.

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