check_garmin_auth

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

Annotations already declare readOnlyHint and idempotentHint, and the description adds valuable context beyond those: it uses a 'cheap authenticated request' rather than a local expiry check, explains why Garmin's session cookie lacks reliable expiry, and states the tool 'never throws.' This is useful behavioral detail the annotations do not convey.

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 with no filler. It fronts the core purpose, then provides rationale and usage direction. Every sentence contributes necessary information about when and how to use the tool.

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, read-only check tool with idempotent annotations and no output schema, the description is complete. It explains the purpose, the execution strategy, the failure mode, and the recommended next step. Nothing essential is missing 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 ambiguity. The description appropriately omits parameter details, and the baseline for a zero-parameter tool is a 4.

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 identifies the tool as a probe for Garmin Connect session validity, using the specific verb 'Probe' and a distinct resource (stored session state). It also differentiates itself from the sibling tools by framing it as a preliminary check before 'whether the other tools will work.'

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 explicitly says 'Use this first when unsure whether the other tools will work,' giving a direct when-to-use instruction. It also names the alternative path, 'run authenticate_garmin if the session is missing or has expired,' making the decision clear.

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