get_hydrometers

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

With no annotations, the description carries the safety burden. It implies a read-only operation by saying 'List all,' and it discloses the returned fields (current gravity, temperature, battery level). Yet it does not mention account authorization, potential stale data, or that results may include unpaired devices, leaving some behavioral uncertainty.

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 a single clear sentence that front-loads the action and resource, then lists the returned data. Every word adds value with no filler or redundancy.

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 parameterless list tool, the description adequately covers purpose and return fields. Without an output schema, it provides enough context for an agent to understand the summary data. It could mention explicit alternatives for single-device or telemetry details, but that is not essential given the tool's simplicity.

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 has zero parameters, and the schema is at 100% coverage (empty object). Per guidelines, a baseline of 4 applies since there are no parameters to explain; the description appropriately adds no redundant parameter details.

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 'List all hydrometers' and identifies the resource as 'RaptPill devices in the RAPT account.' It clearly distinguishes from sibling tools like get_hydrometer (single device) and get_hydrometer_telemetry (historical data).

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 clearly states this returns all hydrometers and current readings, implying use cases for overview vs single-device or telemetry. However, it does not explicitly name alternatives or state when not to use it, so it falls just short of a 5.

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