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

Annotations already establish this as a read-only, closed-world computation. The description usefully adds that the result includes energy consumed and approximate miles added, which annotations cannot convey, but it does not address AC vs DC modeling, rounding, or assumptions behind the estimate.

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?

One dense, front-loaded sentence that leads with the primary output (duration) before the secondary outputs. Efficient, though the trailing clause about energy and miles is slightly compressed.

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 pure read-only calculator with no output schema, the description covers what it computes and what comes back. Optional parameters are fully documented in the schema, so remaining gaps (AC/DC assumptions, rounding) are minor rather than blocking.

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%, so all seven parameters are self-documenting including the DC flag and the AC/DC car rate defaults. The description only restates 'charger power' and 'two battery levels' at a conceptual level, adding no syntax or constraint detail beyond the schema baseline.

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?

States a specific computation: charge duration between two battery levels at a given charger power, plus the derived energy and mileage outputs. The resource (EV charging time) is unambiguous and clearly distinct from siblings like charger_size or area_charging_facts, though it does not explicitly name a sibling.

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?

No when-to-use, when-not-to-use, or prerequisite guidance is given. The agent can infer this is a calculator from the parameter-shaped phrasing, but nothing routes it here versus charger_size or area_charging_facts.

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