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

No annotations are provided, so the description must stand alone. It implies a read-only calculation but does not explicitly state safety (e.g., no side effects, rate limits). The return shape is mentioned, but broader behavioral traits are absent. A 3 is appropriate given the missing annotation support.

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. The first sentence front-loads the purpose and key details. The second adds return structure and a sibling reference. No filler or unnecessary words.

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 simple one-parameter calculator, the description covers the purpose, constraint (2026), output, and related tools. It does not include examples or range hints, but the output schema (mentioned in context) likely fills gaps. Overall adequate.

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% with the parameter co2_g_km described as 'CO2 emissions in g/km'. The description adds the tool's domain (French malus) but no extra parameter details. Standard baseline of 3 for high coverage.

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 states it computes the French ecological malus for 2026 based on CO2 g/km for new vehicle registration, and specifies the return fields {malus_eur, threshold, max}. It distinguishes itself from siblings by naming a specific tax calculation.

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 provides context (French 2026 malus for new vehicles) and directs to list_bundles for related 'auto-transport' calculators. It does not explicitly state when to use or not use this tool, but the context is clear enough.

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