get_sleep_periods

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

With no annotations, the description carries the behavioral burden, and it does disclose the returned fields and period-type taxonomy. It does not mention pagination/truncation, response size, or timezone/date-boundary behavior, even though the next_token parameter implies large results may be cut off.

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 front-loaded with the concrete purpose and then gives a useful, finite list of returned metrics. The period-type explanation earns its place, though the metric list is slightly dense and could be tightened without losing meaning.

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 read tool with a rich output schema and fully documented parameters, the core behavior is sufficiently described. The main missing context is selection guidance among the many sleep/readiness siblings and pagination caveats, so an agent may not know when this call is the right one.

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 100%, and each parameter (start_date, end_date, next_token, include_time_series) already has a meaningful description, so the baseline applies. The prose mostly describes output content rather than parameter behavior, adding little beyond what the schema already provides.

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 the exact resource ('sleep periods') and enumerates the returned metrics (bedtime start/end, sleep-stage durations, heart rate, HRV, breathing rate, readiness), which goes well beyond a vague getter. The distinction between 'long_sleep', 'sleep', 'late_nap', and 'rest' also separates this period-level tool from daily sleep-summary siblings.

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 phrase 'detailed sleep periods' and the explanation of period types imply it is for period-level sleep breakdowns rather than daily summaries, so usage is inferable. However, no alternative tool is named and no explicit when/when-not conditions are given, leaving some selection judgment to the agent.

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