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

Annotations already declare readOnly/idempotent/non-destructive, so the safety profile is covered. The description adds real behavioral content beyond that: it is a two-in/two-out solver that computes the remaining quantities rather than a single-value converter. It does not say what happens with invalid input counts (zero, one, or three values).

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 sentence that front-loads the domain and immediately states the input contract. No filler, no restatement of the title.

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?

An output schema exists, so return values need no explanation, and the description covers the core compute contract. The one gap is the interaction between 'exactly two' and the schema defaults (r and v), which an agent could read as satisfying the two-value rule on their own.

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 100%, so the baseline is 3, but the description adds a constraint the schema lacks entirely: exactly two of the four quantities must be supplied. This matters because the schema exposes defaults (r=24, v=120) with no minProperties/maxProperties, leaving ambiguity the description partially resolves.

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 domain (Ohm's law and power) and the exact operation (solve for the two missing quantities), which clearly separates it from siblings like watts_to_amps or voltage_drop. It does not, however, explicitly contrast itself with any sibling tool, so it stops short of a 5.

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 'give exactly two of voltage, current, resistance and power' rule is a genuine usage constraint that tells the agent how to call the tool. It gives no guidance on when to prefer this over watts_to_amps or load_calculator, and no exclusions or edge-case handling.

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