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

Annotations already declare readOnlyHint, idempotentHint, and closed-world, so the safety profile is covered. The description adds one genuine behavioral fact beyond that: the result is conditional (a VAT amount vs. a franchise-en-base indication), which matters for interpreting the response. It omits any mention of how the optionTVA or deductible-VAT inputs change the outcome.

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 front-loaded sentence with the calculation target stated first and the conditional outcome second. No filler, no restatement of the tool name.

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 six parameters, no output schema, and partial schema descriptions, the description should clarify the required turnover input and what the response contains in the franchise case. It hints at the two possible outputs but leaves the enum and the required numeric input undocumented.

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 67%, leaving 'activite' (enum, undescribed) and the required 'caHTAnnuel' with no descriptive text anywhere. The description only alludes to these two inputs and adds no semantics for the enum values, the optionTVA switch, or the deductibility inputs beyond what the schema already says.

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: compute VAT to charge (facturer) and remit (reverser), or return the base franchise regime, depending on activity and turnover. That is clearly a calculation tool, distinguishable from the neighboring 'seuils_micro_entreprise' only indirectly – the description never says whether it tests thresholds or just applies them.

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?

Usage is implied by the inputs (activity + annual turnover), but the description gives no explicit when-to-use or when-not-to-use guidance and names no sibling as an alternative. An agent cannot tell from the text alone whether to call this or 'seuils_micro_entreprise' first.

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