Get the authenticated user

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint=false, which establish safety. The description adds meaningful behavioral context: it is low-cost, returns plan tier/caps conditionally, and explicitly notes that plan data does not gate connections. This goes beyond the annotations and helps set expectations without contradicting them.

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 fluff. The primary return value is stated first, followed by the usage context and an important caveat. Every sentence earns its place, making it easy to read and quick to parse for an agent.

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 has no parameters and an output schema exists, the description is complete. It covers what is returned, when it is appropriate to call, and clarifies the meaning of plan data. An agent can confidently invoke it without needing additional information.

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 fully covered (100%), so there is no need for parameter-level explanation. The description correctly focuses on return values. Per the baseline for 0-param tools, a score of 4 is appropriate; the description could mention that no input is required, but the empty schema already implies this.

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 ('Return') and resource ('authenticated account'), plus the optional plan tier and caps. It clearly conveys the tool's purpose and differentiates it from calendar-related siblings by framing it as an authentication check rather than a data retrieval operation.

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 gives clear context for when to use it: as a low-cost authentication check to distinguish a bad token from an empty calendar. It also explains that plan data provides limits but does not gate the connection, helping agents understand its role. However, it does not explicitly state exclusions or alternatives, so it earns a 4 rather than a 5.

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