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

Far exceeds the annotations' safety profile: it discloses hard timing rules (2016/1103 and Rome III require nationality at agreement time), a voiding condition (Swiss professio juris void if Swiss nationality later acquired), situs overrides, the fixed-share vs discretionary-claim trade-off, the no-useful-election outcome, the declaration requirement, and an explicit information-only disclaimer. No contradiction with readOnlyHint/destructiveHint/openWorldHint.

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?

Purpose and inputs are front-loaded in the opening clauses, and the later clauses carry genuine behavioral detail (timing, voiding, trade-offs, disclaimer). The single dense sentence-chain is information-rich but heavy to parse; a small amount of structural separation would improve scanning.

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 an output schema present, return-value explanation is unnecessary, and the description covers the domain scope, timing rules, failure mode, and legal caveats. For a zero-required-parameter analytical tool with 5 well-documented inputs, nothing essential is missing beyond sibling routing.

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 each parameter is documented in the schema, so the baseline is 3. The description adds one constraint ('Pass ISO alpha-2 codes only, never personal data'), but that conflicts with the schema's own note that spouse_nationalities is 'as country names' with example ['Brazil'], leaving format ambiguity the description does not resolve.

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 analytical task (determine which law governs cross-border succession, matrimonial property and divorce) with named legal instruments and the exact inputs it consumes and outputs it produces. An agent can distinguish it from siblings like succession_conflict_map or matrimonial_regime_screen from the description alone.

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 through the stated inputs (nationalities, residence, situs, marital status) and the note that it returns 'no-useful-election' when nationality opens nothing. However, it never says when to prefer this over the adjacent siblings (succession_conflict_map, forced_heirship_risk, matrimonial_regime_screen), so routing remains inferential.

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