Eight Sleep Nightly Summary

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

Annotations already declare readOnlyHint, openWorldHint, idempotentHint, and non-destructive behavior. Beyond that, the description clarifies that this tool performs aggregation/derivation from trend data rather than simply returning raw records, and it names the upstream data source. This adds meaningful behavioral context without contradicting the annotations.

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 two sentences with no filler. It front-loads the tool's purpose and output specifics, then adds the key sibling distinction. Every sentence earns its place.

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 simple, zero-required-parameter tool with rich annotations and an output schema, the description covers the core purpose, the computed outputs, and the relationship to get_trends. It is slightly incomplete on timezone semantics and response format, but the schema's defaults and enum constraints give an agent enough to invoke it correctly.

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% and the description does not explain the three parameters (days, timezone, response_format). It offers only indirect hints like 'multi-night' and the score thresholds, which do not compensate for the missing parameter documentation.

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 ('Compute') with a clear resource ('multi-night sleep summary') and enumerates exact outputs: best night, worst night, mean score, and counts of nights below 70 / above 85. It also distinguishes itself from the sibling get_trends by explicitly stating it replaces post-processing of that raw tool.

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 names get_trends as the alternative and explains that this tool eliminates the need to post-process raw trend data. It provides clear context for when to prefer this tool, though it does not explicitly state when not to use it (e.g., if raw individual night data is needed).

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