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

Annotations already declare readOnlyHint=true, and the description does not contradict this. It adds useful behavioral context beyond the annotation: it runs the same engine as an external calculator, produces a verdict only when an existing service is provided, and handles EMS-managed load only when an EMS is declared.

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?

The description is a single well-packed sentence that puts the core purpose first and then enumerates outputs in a scannable list. It is dense but not bloated; every clause adds information, though splitting it into short sentences or bullets would improve readability slightly.

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?

Given that there is no output schema, the description usefully enumerates the main computed results and the conditional verdict behavior. It also communicates the planning-only scope. It does not spell out required inputs, but the schema already covers those, so the description is sufficient for a competent agent to invoke the tool correctly.

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 only 43%, so the description must compensate, and it partially does by explaining the role of code editions, EMS, chargers, and existingService. However, it does not clarify less obvious parameters such as siteType, servicePhase, serviceVoltage, or charger sub-fields like dcfcBasis and ratingKw beyond what the schema already states.

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 clearly identifies the tool as an EV-charging service capacity estimator powered by a specific engine, and lists its concrete outputs: code load, EMS-managed load, planning-basis load, transformer kVA, service rating, and a GREEN/YELLOW/RED verdict. It is clearly distinct from sibling tools like get_product or search_knowledge.

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 description gives clear context for when to use the tool: for planning estimates of EV-charging service capacity under specific code editions. The phrase 'Planning estimate only' acts as an exclusion against using it for final engineering designs, though it does not explicitly name alternative tools.

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