Check the Vinted session

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

Even with readOnlyHint=true, the description adds valuable behavioral context: 'without throwing' indicates error-handling behavior, and it explains the login requirement and explicitly instructs never to ask for the user's password, which is critical safety guidance.

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 three sentences, front-loaded with the main purpose, and each sentence earns its place: function, usage scenario, and login safety guidance. No waste or redundancy.

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 status-checking tool with no mandatory parameters and no output schema, the description is complete. It covers what the tool does, when to use it, what it returns (absent vs expired), and critical login instructions.

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 100% coverage for the 'country' parameter, including its description and default behavior. The tool description adds no new parameter-level details beyond restating the country concept in the login command, so baseline 3 is appropriate.

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 function with a specific verb ('Reports') and resource ('usable Vinted session'), and explicitly differentiates it by noting it returns 'absent' vs 'expired' statuses without throwing, which no sibling tool does.

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 provides explicit guidance on when to use: 'Use it when a seller tool fails, to tell the user precisely whether they have never logged in or their session lapsed.' This gives clear context and distinguishes it from any alternatives.

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