device_metrics

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

Annotations already mark this as read-only and non-destructive. The description adds useful behavioral context beyond that: it defaults to the last 24 hours, and the metric set is codec-defined, meaning output can vary by device codec. No contradiction with 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?

Two short sentences with no filler. The core content is front-loaded, and the default time window is stated efficiently.

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?

With four parameters, an output schema, and a close sibling in gateway_metrics, the description is too sparse. It omits aggregation granularity, start/end semantics, and any guidance for choosing between device_metrics and gateway_metrics. The output schema helps, but the input contract remains under-specified.

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 compensate for undocumented parameters. It clarifies the default time window, which maps to start/end, but it does not explain what dev_eui identifies, how aggregation affects results, or the expected start/end format. Three of four parameters remain underexplained.

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 identifies the resource as device metrics and lists concrete content: RSSI, SNR, packets per frequency/DR, errors, and codec-defined metrics. It is clear this is about device-level link quality, though it lacks an explicit retrieval verb and does not directly contrast with gateway_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 usage context is implied by the name and content: an agent would use this when it needs device-level link-quality and codec-defined metrics. However, the description does not explicitly say when to prefer this over gateway_metrics or other sibling tools, and it provides no exclusions.

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