List daily health metrics

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

Annotations already declare read-only/idempotent, but the description adds materially new behavior: fields appear only on days Oura computed them (VO2 max and cardiovascular age are sporadic), the default window is 7 days, and the response includes an `unavailable` list for data types the user didn't grant. That permission-gap disclosure is exactly the kind of context annotations cannot carry.

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?

Front-loads the resource and field list, then usage routing, then range rules and return shape. It is dense and somewhat long, but nearly every clause carries operational information that the schema does not.

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?

Despite having no output schema, the description documents the return shape ({ records } oldest first plus `unavailable`), data sparsity behavior, and full range semantics. An agent has everything needed to call and interpret the result.

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 the baseline is 3, but the description adds real meaning: the range is inclusive, the default is the last 7 days, days caps at 400, and days is ignored when start is set. The inclusive semantic is not stated in the schema itself.

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?

Names a specific verb and resource (list per-day health metrics) and enumerates the exact fields returned: stress, resilience, SpO2, breathing disturbance, cardiovascular age, VO2 max, bedtime guidance. It explicitly distinguishes itself from siblings by noting readiness, sleep and activity scores live in their own list_* tools.

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?

States intended use ('for stress, resilience, breathing and cardio-fitness trends') and routes the agent away from this tool for readiness/sleep/activity via named sibling tools. Both when-to-use and when-not-to-use are covered.

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