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

Annotations declare readOnlyHint=false, idempotentHint=false, destructiveHint=false. The description adds substantial context beyond this: 'CONSOMME le quota d'export du plan' reveals a quota side effect, the dual execution paths (inline vs server-side file with jobId) disclose async behavior, plan caps (20 000/50 000 lignes) are quantified, and maxRows/capped semantics explain result truncation. No contradiction with annotations — consuming quota is consistent with non-read-only, non-destructive.

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?

Every sentence earns its place: purpose, quota warning, mode rule, count-first prerequisite, execution paths, plan limits, and result semantics. The information is front-loaded (purpose and quota warning first), and the two-path workflow is presented with clear thresholds. Though dense, the length is justified by the tool's operational complexity — this is efficiency, not bloat.

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 4-param tool with nested filters, an output schema, async file export, and quota constraints, the description covers the critical operational surface: prerequisite (count first), automatic path selection with exact thresholds, follow-up status tool, plan caps, and response flags (maxRows, capped). The only minor gap is a concrete example of the open-ended filters object, but the 100% schema coverage and existing output schema mitigate this.

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%, so the baseline is 3. The description adds a meaningful decision rule for `mode` — '1 ligne / entreprise, défaut' vs '1 ligne par POINT DE VENTE / établissement Google — à utiliser quand establishmentsTotal > total' — which goes beyond the schema's enum listing. It also reinforces the ids-vs-filters alternative. A concrete filters example would push this to 5, but the schema already documents all parameters well.

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 opens with a specific verb+resource+scope: 'Exporte un CSV COMPLET (~70-79 colonnes) pour des filtres OU une liste d'ids.' It clearly distinguishes the tool from its siblings: basile_count counts, basile_export_status checks status, basile_search_* and basile_suggest search/suggest, while this is the only exporter. An agent can identify its role immediately.

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 gives explicit operational guidance: 'Compte d'abord (basile_count)' establishes the prerequisite, 'via basile_export_status' names the follow-up tool, and 'à utiliser quand establishmentsTotal > total' gives a concrete selection rule for the locations mode. The two execution paths (inline ≤500 lines vs file >500 lines) are spelled out with exact thresholds, leaving nothing to inference.

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