Icu Get Hr Histogram

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

Annotations already declare readOnlyHint, idempotentHint, non-destructive and openWorld, so the safety profile is covered. The description adds a real behavioral distinction beyond that: results are scoped to one activity and expressed as bucket/time-per-bucket rather than cross-activity best efforts. No auth, rate-limit, or cost notes, which keeps it from a 5.

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 fragments, front-loaded with the core result shape, then the sibling contrast, then the use case. No repetition of the name and no wasted clauses.

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?

An output schema exists, so return-value explanation is correctly omitted; the description covers purpose, scope, and the main alternative. Only marginal omissions remain (e.g., what happens if the activity lacks HR data), which are low-risk for a read-only single-parameter tool.

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% and the single parameter is self-documented as 'Activity ID to analyze', so the description adds nothing about the parameter. Baseline 3 applies when the schema carries the full burden.

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 (time-in-zone distribution of heart rate) plus an explicit scope: a single activity, with histogram buckets and time per bucket. It also names the sibling it is not (icu_get_hr_curves, best efforts across many activities), so an agent can separate it from the multi-activity curve tools without opening a schema.

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 concrete usage context ('cardiovascular load breakdown and HR-zone time-in-zone') and explicitly routes the multi-activity best-efforts case to icu_get_hr_curves. No explicit when-not conditions or mention of the pace/power histogram siblings, so it falls short of the top tier.

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