Check mobile API auth status

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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, but the description adds critical behavioral context: 'Read-only; no network call.' This goes beyond the annotations by specifying that the tool performs no network request, implying it is a local in-process check. This is additional transparency that helps the agent understand the tool's runtime behavior and side effects. No contradiction with annotations 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?

The description is three sentences, each carrying essential information: the primary purpose, the usage context and diagnostic role, and the follow-up workflow plus safety note. It is front-loaded with the core function and avoids any redundant phrasing. Every sentence adds value, making it both concise and well-structured.

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 that the tool has no parameters and an output schema exists (so return values are presumably covered elsewhere), the description is fully complete. It explains what the tool does, when to use it, how to handle the negative case (no token), and its non-network nature. No additional information is needed for an agent to invoke it correctly.

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 has zero parameters and the schema is empty, so there is no parameter semantics to document. The baseline of 4 applies for tools with no parameters; the description does not need to add anything here, and it correctly avoids inventing irrelevant parameter details.

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: 'Report whether a mobile API access token is loaded in this server process.' It specifies the exact resource (mobile API access token) and the action (report status), and distinguishes itself from sibling tools like auth_start and auth_exchange by being a status check rather than an authentication action. This leaves no ambiguity about what the 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?

The description provides explicit when-to-use guidance: 'Use as a first check before account-scoped tools (cart, profile, order, add_to_cart), or to diagnose "not authenticated" failures.' It also gives a concrete alternative workflow: 'If no token is loaded, run auth_start, have the user complete the browser sign-in, then auth_exchange.' This directly instructs the agent on the proper usage context and fallback steps, fully satisfying this dimension.

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