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

Annotations already establish readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safety profile is covered. The description adds meaningful behavioral context beyond annotations: it computes an annual bill, compares market offers to the regulated tariff, and estimates savings. It does not detail data sources or assumptions, but for a read-only simulation this is solid transparency.

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 sentences with no filler, the main action is front-loaded, and the comparative/savings purpose follows naturally. Every clause earns its place and the description is easy for an agent to scan.

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?

With a high-coverage schema, clear annotations, and an output schema present, the description covers what the tool does well enough for invocation. The main gap is explicit sibling routing, captured in usage_guidelines, and minor lack of caveats about market-offer data, but nothing critical is missing for a read-only simulation tool.

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 80%, so most parameters are already well-documented in the schema, including the conditional proportion_hc rule. The description itself adds no parameter-level explanation beyond the overall simulation and savings context. This matches the baseline expected when the schema carries most of the semantic weight.

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 verb and resource: 'Simule la facture annuelle d'électricité pour un foyer français.' The additional clause about comparing market offers to the regulated tariff and estimating savings clearly distinguishes it from bill-analysis or invoice-annualization siblings like analyze_bill, annualize_invoice, and renewal_advisor.

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 implies the use case—simulating a French residential annual electricity bill and comparing offers—but it never explicitly states when to prefer this tool over alternatives or when not to use it. Given the large sibling set, an agent gets no direct routing or exclusion guidance, only inferred context.

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