get_sleep

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

With no annotations provided, the description carries full burden for behavioral disclosure. It clarifies the scope ('for one night'), the time interpretation ('last night' and 'today' both mean the most recent night), and lists the fields returned. A minor gap: it does not state whether the tool is read-only (implied by 'get') or if it modifies data, but the description is otherwise transparent. No contradiction since there are no annotations to contradict.

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 concise at two sentences plus a bulleted Arg section. The main sentence front-loads the purpose. The Arg section is clear. However, the bullet list under 'Args' could be tightened—'day:' followed by a newline and explanatory text feels slightly less structured than ideal, but overall it's efficient.

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?

Given the tool has 1 optional parameter, high output schema (covers return fields), and no required parameters, the description is quite complete. It explains the parameter, the tool's scope, and what data is returned. It might benefit from stating that it returns the most recent available sleep data if 'day' is omitted, but the default 'last night' hints at this. No significant gaps remain for the agent's selection and invocation.

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 0%, so the description must fully explain the parameter. It does: 'day' is described as 'The night's date', with example values including 'last night', 'today' (both meaning most recent night), 'yesterday', and a specific date format '2026-08-18'. This adds rich meaning beyond the schema's minimal type and default.

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 uses a specific verb ('get') and resource ('sleep for one night'), and clearly lists the exact breakdown of data returned (total time, deep/light/REM/awake breakdown, sleep score, resting heart rate, breathing). It also implicitly distinguishes from sibling tools like get_daily_summary and get_hrv by focusing on sleep-specific metrics.

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 description provides clear guidance on when to use this tool (for retrieving sleep data for a specific night) and includes helpful details on date input formats ('last night', 'today', 'yesterday', '2026-08-18'). However, it does not explicitly tell when not to use it or mention alternatives among siblings for broader summaries or other metrics.

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