measure

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

With no annotations, the description carries the full burden and does meaningful work: it discloses units (V, A, W, °C), that samples are taken interval_ms apart, that mean/min/max are computed for three of the fields, and the sign convention for positive current (receptacle to plug). It stops short of stating how long a multi-sample call blocks or what errors/permissions apply.

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 tight paragraphs, zero filler, with the measurement set front-loaded and the sampling/aggregation behavior immediately after. Every sentence (units, interval semantics, sign convention) 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?

No output schema exists, so the description must describe returns — it names the measurement channels and the specific fields that get mean/min/max treatment. Combined with the sampling semantics, an agent has enough to call this correctly and interpret the result.

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 coverage is 0% and the two params have only bare titles and defaults, so the description must compensate — and it does: samples is explained via 'with samples > 1 the readings are taken interval_ms apart', and interval_ms is given real meaning as the spacing between samples. Aggregation behavior (mean/min/max) tied to samples > 1 adds semantics the schema entirely lacks.

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?

Opens with a specific verb ('Read') and enumerates the exact resources measured (VBUS/IBUS/power, CC1/CC2, D+/D-, VDD, temperature), so an agent knows precisely what this returns. It does not explicitly distinguish itself from siblings like device_info, pd_status, or stream_samples, leaving the one-shot vs. streaming distinction to be inferred.

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?

Implicit guidance is present: 'with samples > 1' tells the agent when to use averaging mode, and the default samples=1 implies the simple single-reading case. However, there's no explicit statement of when to prefer this over stream_samples or pd_status, and no prerequisites (device connection/claim state) are given.

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