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

Beyond the annotations (readOnlyHint=false, destructiveHint=false, idempotentHint=false), the description discloses a cross-resource side effect — the lot is marked rented — and a refusal condition when the lot already has an active lease, which is exactly the kind of guard an agent needs before attempting a write. It does not mention permission/admin-key requirements for `abonne`, but the schema covers that.

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?

The description is front-loaded with the use condition, then the read path, then the write path plus the refusal rule, with no filler sentences. Dense parenthetical enumerations and French/English mixed field names make it slightly harder to scan, but nothing is wasted.

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 dual-mode tool with an empty nested object schema and no output schema, the description supplies the return fields for listing, the full creation payload shape, and the failure condition. Remaining gaps — pagination behavior and the exact return shape after creation — are modest given the schema and annotations already present.

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?

The schema leaves `creer` as an untyped bare object with zero documented sub-properties, so the description carries the entire burden — and it does, enumerating lot_id, tenant_id, start_date with the YYYY-MM-DD format, rent, optional charges/deposit/payment_day/duration_months, and lease_type enum values (habitation_vide, habitation_meublee, commercial…). This is meaning genuinely unavailable in the structured schema.

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 states a specific verb and resource and explicitly splits the two modes: listing ("Lists them (lot, tenant, rent, status)") versus creation ("with `creer` ... creates an active lease and marks the lot rented"). The resource is distinguishable from siblings like immo_biens or immo_locataires by the lease framing, though no sibling is named explicitly, which keeps it just below a 5.

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?

"WHEN you need the subscriber's leases" gives a clear triggering condition, and the description states the selection rule between the two modes via the presence of `creer`. It does not name alternatives (e.g. a tenant-oriented tool) or exclusions, so it is strong context without full routing guidance.

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