oura_spo2

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

Annotations already declare readOnlyHint, idempotentHint, and destructiveHint, so the description doesn't need to repeat safety traits. It adds some behavioral context by specifying 'average nightly' and the default date behavior, but doesn't elaborate on edge cases like missing data or timezone handling. This is adequate given the annotation coverage, but not rich.

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 concise sentence stating the purpose, followed by a minimal parameter explanation. It is front-loaded with the core functionality and contains zero redundancy. Every element earns its place.

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 simple one-parameter tool with output schema present, the description adequately covers the essential details: what data is returned and how to specify the date. It doesn't mention finer points like how 'nightly' is defined or timezone handling, but these are minor for a straightforward retrieval tool. The presence of an output schema reduces the burden of describing 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?

Schema description coverage is 0%, so the description must compensate for the 'date' parameter. It does so by providing the format ('YYYY-MM-DD') and the default value ('defaults to today'), which the schema lacks. This adds meaningful semantics beyond the bare schema definition, though it could mention accepted ranges or validation constraints.

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 specific operation ('Get') and the resource ('average nightly blood oxygen (SpO2) percentage for a date'). It uniquely identifies the metric (SpO2) which distinguishes it from all sibling tools that handle other Oura data types, so there is no ambiguity about what this tool returns.

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 provides no guidance on when to use this tool versus alternatives. It doesn't mention any exclusions, conditions, or relationships with sibling tools like oura_sleep or oura_daily_summary. An agent must infer from the metric name alone that this is for blood oxygen data, but no explicit selection guidance is given.

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