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

With no annotations, the description carries the full burden and usefully discloses non-obvious behaviors: first-login activation, automatic selection for the MCP session, and that it does not replace the Control Panel. However, it still omits permission requirements, error cases, and whether creation is reversible or how it affects existing sites.

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 with no filler: the first front-loads the action and side effects, and the second adds a relevant limitation. Every sentence earns its place.

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 creation tool with full parameter schema coverage but no annotations or output schema, the description covers the core operation and key side effects. It is nearly complete, though it could mention auth scope details or failure behavior.

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 schema already documents all three parameters, including the enum mapping for dom and the format for addr. The description adds no additional parameter meaning, which is acceptable given full 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 states a specific verb (Create) and resource (site), and it also names two important side effects: first-login activation and session selection. This distinguishes it from siblings like select_site and list_sites without needing their schemas.

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 the tool is for creating a new site under the authorized account, but it does not explicitly state when to use it versus alternatives such as select_site or list_sites. The note about the Control Panel flow is contextual, not a usage guideline.

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