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

Annotations already mark this as readOnly and non-destructive. The description adds useful behavioral context beyond that: 'Works without login' and 'Returns the one right next step', making clear it is a classification/advice tool rather than an authentication action. No contradiction exists.

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 dense sentences carry all essential information: what the tool classifies, the possible outputs, the nature of the response, and the no-login requirement. There is no filler or repetition of schema content.

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?

Given there is no output schema, the description compensates well by naming the exact classification categories and stating that it returns the next step. It could specify the output representation more explicitly, but for a single-input classification tool the description is sufficiently complete for correct selection and invocation.

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 the single server_url parameter is already documented. The description reinforces that the URL is an MCP server URL to classify, but it does not add format details or constraints beyond what the schema provides. 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 uses a specific verb ('classify') and resource ('any MCP server URL'), then enumerates the four possible classification outcomes. It clearly distinguishes itself from action-oriented siblings like auth_connect and auth_connections by stating it 'returns the one right next step' rather than performing authentication.

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 context is clear: use this tool to determine how to authenticate a given MCP server URL, and it works without login. It does not explicitly name sibling alternatives or provide when-not-to-use conditions, so it falls short of a 5, but the intended trigger is strongly implied.

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