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

The description discloses the optional snapshot persistence, which is a key behavioral trait. However, with no annotations, it does not mention the destructiveness of closing (e.g., irreversibility, whether the session becomes invalid) or any expected return behavior. It provides basic transparency but leaves room for more.

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 a single, concise sentence that packs the core action and an optional variant. No unnecessary words, front-loaded with the verb and resource.

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 simple tool with one parameter, the description is adequate but lacks details about return values, edge cases (e.g., closing an already-closed session), or post-conditions. No output schema or annotations exist, so the description could have offered more context, but the tool's simplicity keeps the score at a passing level.

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 fully describes the single parameter (session_id as Session UUID), so the description adds no extra meaning. With 100% schema coverage, the baseline of 3 is appropriate; the description does not need to compensate.

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 action: 'Close a session' and adds an optional behavior: 'persist a snapshot of its final state'. It distinguishes itself from sibling tools like create_session (opposite) and get_session_state (read-only), making the tool's purpose unmistakable.

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 description implies usage (closing a session) but does not explicitly state when to use it versus alternatives, such as retrieving state before closing or whether there are prerequisites. No exclusions or alternative recommendations are provided.

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