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

Annotations already mark this as read-only and non-destructive, but the description adds critical behavioral context: using it as a preflight swallows the 401 that would otherwise trigger OAuth. It also discloses the return shape at a high level (authenticated boolean, tier roles, wallet flag, never raw tokens), which is valuable for a zero-parameter auth tool.

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 warning about not using this as a preflight is front-loaded and the remaining sentences each add necessary routing, behavioral, or return-value context. Nothing reads as filler, and the quoted examples make the usage condition concrete.

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 zero-parameter auth-status tool with rich annotations and an output schema, the description supplies exactly the missing operational context: when it is valid, when it is harmful, and what class of data it returns. An agent has enough information to invoke it correctly or avoid it appropriately.

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 tool takes zero parameters, so there are no parameter semantics to explain; the baseline for a zero-parameter tool is 4. The description correctly does not waste space documenting nonexistent inputs.

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 makes the tool's purpose unmistakable: checking whether the user is signed in to the XP marketplace and returning auth state. It also distinguishes this diagnostic/status tool from protected sibling tools, so an agent can tell it apart without inferring from the name alone.

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 gives explicit when-to-use conditions, quoted user intents, and a clear after-AUTH_REQUIRED re-check case. It also gives an equally explicit DO NOT preflight rule and explains the alternative: call the requested protected tool directly and let the client trigger OAuth on 401.

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