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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, openWorldHint=false), so the description is free to add domain behavior — and it does, disclosing the per-enfant application of the 777 barème, the 779 I abattement, the 15-year rappel rule and the parents=2 moiety split. Return format is not described, but the calculation semantics are unusually well exposed.

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?

Front-loaded with the purpose, but it is a single dense run-on paragraph mixing formula, article citations and exclusions. Every clause carries information, yet the wall-of-text form makes it harder to scan than a structured two-or-three sentence version.

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?

No output schema exists, so the description must convey what is returned — and it does (droits dus par enfant, droits évités par donation, tranche marginale sur 100 000 €, plus the article sources). Only the exact return shape/field names are left unspecified.

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% and the schema already documents all three params, so baseline is 3. The description goes further by explaining the operational consequence of parents=2 (two successions, each on half the assets, 100 000 € abattement per parent per child), which the enum alone does not convey.

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?

Names a specific computation: droits de succession en ligne directe plus the donation savings (art. 784), with the exact tax base (actif net transmissible, per-child abattement). An agent can distinguish this from fiscal_ifi or fiscal_tmi without opening the schema.

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?

Gives clear context (direct-line succession, children heirs) and an explicit scope exclusion: 'Hors assurance-vie (art. 990 I / 757 B)' and 'Même calcul que l'étude patrimoniale (cTR)'. It does not however name a sibling tool to use for the excluded assurance-vie case.

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