battery

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

With no annotations provided, the description carries the full behavioral burden, and it discloses nothing: no read-only/no-side-effect statement, no indication of whether the device must be connected or authorized, and no note about behavior when multiple devices are present. Only the returned fields are listed.

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?

A single tight phrase with zero filler, front-loading the returned values. It is a fragment rather than a sentence, but nothing is wasted.

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?

The tool is simple and the description covers what data comes back, which substitutes for the absent output schema. However, for a tool with no annotations it should at least confirm this is a side-effect-free read and clarify device-selection behavior, which it does not.

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% for the single 'device' parameter, so the schema already explains serial usage and the single-device omission rule. The description adds nothing about the parameter, so the baseline 3 applies.

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 specific resource and the exact data returned (battery level, charging status, temperature), which clearly separates it from siblings like device_info and storage. It lacks an explicit verb, but for a single-purpose telemetry tool the intent is unambiguous.

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?

There is no statement of when to use this tool versus device_info or other device queries, and no mention of prerequisites or alternative tools. The agent must infer usage entirely.

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