status

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

With no annotations provided, the description carries full burden for behavioral disclosure. While 'Check' implies a read-only operation, it doesn't specify whether this requires authentication, what specific information is returned (beyond 'status and session info'), or any rate limits/constraints. For a tool with zero annotation coverage, this leaves significant behavioral gaps.

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 a single, efficient sentence that front-loads the essential information. Every word earns its place - 'Check' (action), 'Costco' (context), 'authentication status and session info' (what's checked). No wasted words or unnecessary elaboration.

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 the tool's simplicity (0 parameters, no output schema, no annotations), the description is reasonably complete for a status-checking operation. However, it doesn't specify what information is actually returned or any authentication requirements, which would be helpful context. The absence of an output schema means the description should ideally hint at return values.

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 with 100% schema description coverage, so the schema already fully documents the parameter situation. The description appropriately doesn't discuss parameters since none exist. Baseline for zero parameters is 4, as there's no parameter information to add beyond what the schema provides.

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 purpose with a specific verb ('Check') and target resources ('Costco authentication status and session info'). It distinguishes itself from siblings like login/logout by focusing on status verification rather than authentication actions. However, it doesn't explicitly differentiate from potential status-checking siblings that might exist.

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 usage context (checking authentication/session status) but doesn't provide explicit guidance on when to use this versus alternatives like login or get_membership. No when-not-to-use scenarios or prerequisite conditions are mentioned, leaving usage decisions to inference rather than explicit direction.

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