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

Annotations already establish the safety profile (readOnly, idempotent, non-destructive, openWorld), so the bar is lower. The description adds meaningful context beyond them: the values are 'parsed deterministically from the in-force Flemish Tax Code', which signals authoritative provenance and reliability rather than model-generated guesses.

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 tight sentences, front-loaded with the resource and its provenance. One clause ('Omit categorie to get all three') is a near-duplicate of the schema parameter description, which is the only wasted space.

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 one-parameter, read-only lookup with no output schema, the description conveys what is returned (rate brackets per heir category) and the authoritative source. It stops short of describing the return shape (e.g. bracket ranges vs. flat rates), but that omission is minor.

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 100% and the single parameter's enum and default are fully documented in the schema. The description's 'Omit categorie to get all three' merely restates the schema's own 'Omit for all three' note, adding no syntax or format detail beyond structured data.

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 resource (Flemish inheritance-tax rate brackets) with an explicit legal source (VCF art. 2.7.4.1.1) and coverage scope (all three heir categories). An agent can distinguish this from sibling legal_lookup/legal_search, which are generic retrieval tools.

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 a concrete usage instruction ('Omit categorie to get all three') and an explicit alternative to avoid ('use this instead of reciting rates from memory'). It does not, however, say when to prefer this over the sibling legal_lookup / legal_search tools that could plausibly return the same statute.

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