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

The description explicitly states 'Idempotent: logging the same lounge on the same date updates the existing visit's rating/notes instead of creating a duplicate,' but the annotations declare idempotentHint=false. This is a direct contradiction about whether repeated calls are safe to invoke.

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 sentences, both purposeful. The primary action and identification logic are front-loaded, and the idempotency behavior earns its place as critical usage information.

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 write tool with six parameters and no output schema, the description covers the essential invocation details: what to do, how to identify the lounge, optional fields, and duplicate-handling behavior. It could be more complete by naming sibling alternatives, but nothing critical to calling the tool is missing.

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 100%, so parameters are already documented well. The description adds value by clarifying the identifier alternatives ('slug OR lounge_name + airport_iata') and by indicating that rating/notes update an existing visit on the same date, which the schema alone does not convey.

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 opens with a specific verb and resource: 'Log a lounge visit (check in).' It clearly identifies the action and the target resource, though it does not explicitly contrast itself with sibling tools like update_visit or write_review.

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 intended use is implied by 'Log a lounge visit (check in)' and the identification instructions are clear, but there is no explicit statement of when NOT to use this tool or when to prefer alternatives such as update_visit, delete_visit, or write_review.

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