auth_status

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

The readOnlyHint annotation already signals a safe read operation, and the description adds meaningful context beyond that: it discloses that the token is never returned, a valuable confidentiality guarantee. It also clarifies that server configuration state (writes on/off, dedupe window) is included. It does not address behavior on invalid tokens, but the output schema likely covers response shape.

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?

One tightly written sentence with a colon-delimited list conveys all key behaviors. It is front-loaded with the primary purpose and contains no filler or repetition.

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 parameterless status-check tool with an output schema and a read-only annotation, the description covers the essentials: what is checked, what configuration is included, and a critical security guarantee. Nothing needed to invoke it correctly is missing.

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, so the input schema is trivially complete. The description appropriately focuses on what the tool returns and checks rather than inventing parameter details, matching the baseline for a parameterless tool.

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 action ('Check') and resource ('the YNAB connection'), then enumerates exactly what is checked: token validity, plan list, and server configuration. This clearly distinguishes it from sibling data-listing tools like list_plans or get_transactions.

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 phrase 'Check the YNAB connection' implies this is a status/diagnostic tool to verify authentication and configuration. However, it does not explicitly state when to use this tool versus alternatives, nor when not to use it, leaving some guidance to inference.

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