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

Annotations declare readOnlyHint=false and destructiveHint=false, which the 'creates one in the account' wording is consistent with. The description adds real behavioral context the annotations lack: the 'plan lot limit applies' constraint on creation and the fact that listings return owner, rent and status. It does not cover permissions or failure modes.

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 WHEN trigger, then two compact clauses covering list and create. It is dense and largely waste-free, though the single run-on sentence with a long inline field list is harder to parse than a short structured breakdown.

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 a nested object and no output schema, the description covers the trigger, both modes, creation fields and the lot-limit constraint. Listing coverage ('owner, rent and status') is brief but sufficient given annotations carry the safety profile.

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 `creer` parameter is an opaque nested object in the schema, and the description fully enumerates its fields (owner_id, lot_number, property_type with concrete examples, address, surface, rooms, floor, base_rent, provision_charges, description) while marking the optional ones with `?`. This nearly closes the 67% coverage gap on the most complex parameter.

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 clear dual purpose: listing the subscriber's properties (lots) and, when `creer` is present, creating one. The resource ('properties', 'lots') is unambiguous against `immo_locataires`, `immo_proprietaires` and `immo_baux`, though no sibling is named explicitly to sharpen the boundary.

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?

It opens with the explicit trigger 'WHEN you need the subscriber's properties (lots)' and makes the list-vs-create branch selectable via the presence of `creer`. No when-not-to-use or explicit alternative routing is given, keeping it below a 5.

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