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

The annotations already declare readOnlyHint=true and idempotentHint=true, which cover safety and idempotency. The description adds 'safely' but doesn't elaborate on side effects like session invalidation or whether subsequent calls are meaningful. No contradiction with annotations.

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, short sentence that is front-loaded and contains no unnecessary words. 'Safely' is mildly redundant but not harmful. It earns its place as a concise summary.

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 logout tool with full schema coverage and safety annotations, the description is nearly complete. However, it doesn't mention post-condition behavior (e.g., session_id becoming invalid), which would be helpful for an agent to know. Still, it is adequate given the simplicity.

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 input schema already provides a full description for the single parameter (session_id: 'Your session ID from login/register'). The tool description adds no additional parameter semantics, so the baseline 3 applies due to 100% schema coverage.

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 purpose: 'Safely disconnect from the game'. The verb 'disconnect' identifies the action and 'from the game' identifies the resource. It is unambiguous and distinguishes itself from sibling tools like login and register.

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 when the user wants to end their game session. There are no explicit exclusions or alternatives, but since there is no other logout-related sibling, this is sufficient context. However, 'safely' is vague and doesn't specify any preconditions.

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