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

Annotations already declare readOnly, idempotent and openWorld, so the safety profile is covered. The description adds real value beyond that: the window bounds (1-28), the default (7), the aggregation shape, and the requirement to pass the user's LOCAL date in strict YYYY-MM-DD format.

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?

Three short sentences, front-loaded with the core capability, then the trigger condition, then the critical formatting constraint. No filler and nothing important buried.

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?

There is no output schema, so the description usefully sketches the return shape (per-metric mean/min/max) and defines the input's local-date convention. It doesn't say which metrics are covered or how missing days are handled, but the essentials for a correct call are present.

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 coverage is 100%, so both parameters are already documented in the schema, establishing a baseline of 3. The description's notes about the default window and the local/strict date format largely restate the schema rather than adding new syntax or edge-case meaning.

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?

States a specific verb and resource ('Get a 1-28 day window of daily Oura metrics') plus the aggregation performed (per-metric mean/min/max), so the agent knows exactly what it retrieves. It does not explicitly differentiate itself from siblings like get_daily_summary or get_date_range, which is the only thing keeping it from a 5.

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?

Gives a concrete trigger phrase ('how was my week') and the general intent ('scan the past N days at a glance'), which is enough to route most requests correctly. It never states when NOT to use it or names the sibling tools that handle single-day or raw-range queries.

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