Profile and HR zones

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

The annotations already establish that this is a read-only, idempotent, non-destructive operation, so the safety profile is fully covered. The description adds only the domain content of the payload, with no mention of authentication, account scoping, caching, or what happens when a profile has not been configured.

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?

Two short sentences, front-loaded with what is returned and followed by the usage hint, with no filler. The 'etc.' in the parenthetical slightly weakens the enumeration, but the text is efficient overall.

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?

With no output schema, the description carries the burden of describing return values, and it only partially does so via an open-ended list ending in 'etc.' For a zero-argument getter that is arguably sufficient, but the agent cannot fully anticipate the response shape, and no output schema exists to fill that gap.

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 takes zero parameters, so there is no parameter semantics to explain; the baseline for a parameterless tool applies. Nothing in the description misleads about inputs.

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 names a specific resource (user profile settings and heart-rate zones) and enumerates representative contents such as units, measurement system and birth year, so the agent knows exactly what it retrieves. It does not need to distinguish itself from siblings like get_hrv or get_sleep, which are clearly different resources, but it also makes no explicit contrast.

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 single clause 'Useful context before interpreting training data' gives an implied when-to-use signal, which is more than nothing. However, it offers no exclusions, no ordering relative to sibling calls, and no statement about whether this must be fetched before other tools.

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