oura_ring

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

Annotations already define readOnlyHint, idempotentHint, and destructiveHint as safe. The description adds that the tool returns all rings and battery readings, and specifies the datetime defaults. It does not contradict annotations and provides useful output details beyond what annotations cover, such as the exact fields returned.

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 two crisp lines: a one-sentence overview and a brief 'Args' list. No filler or redundancy. The core purpose is front-loaded, and the parameter details are clear and minimal, following standard docstring structure.

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 read-only, idempotent tool with no required parameters and an output schema (not shown but present), the description covers the essential purpose and parameter behavior. It explains the purpose, time window defaults, and what data is returned. An agent can call it correctly without 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?

Schema descriptions cover 0% of parameters, so the description must fully explain them. It does so by defining both start_datetime and end_datetime as ISO 8601 with defaults (24 hours ago and now). This gives agents everything needed to construct valid arguments, compensating entirely for the missing schema descriptions.

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 retrieves ring hardware details (model, color, size, firmware) and battery readings for a time window. The specific verb 'Get' and resource 'every ring ever paired' make it unambiguous and distinct from siblings like oura_sleep or oura_activity, which focus on health metrics.

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: when you need ring hardware info or battery data. It provides defaults for the time window, which indicates usage. However, it does not explicitly mention alternatives or when not to use it. Since the tool is uniquely about the ring itself, usage is easily inferred, but a direct comparison to siblings would elevate it to 5.

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