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

Annotations already declare readOnlyHint=true and idempotentHint=true, so no contradiction exists. The description adds useful context about which fields are returned and explicitly excludes owner data. Yet the undefined 'twin' claim is vague and may confuse rather than clarify what behavior to expect.

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 compact and front-loaded with the input format and core outputs, achieving conciseness without padding. The second sentence is slightly cryptic, especially the twin reference, but it still covers both inclusions and exclusions in a short span.

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 single-parameter tool with rich read-only annotations, the description gives the key inputs and outputs and notes the owner omission. The main gap is the unexplained 'jumeau' relationship, which leaves an agent unsure what additional data exists or where to find it, so the description is not fully self-sufficient.

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 alone already gives the parameter pattern and an example, achieving 100% coverage. The description adds semantic structure by decomposing the identifier into INSEE code, prefix, section, and number, which goes beyond the schema's raw pattern and aids correct construction of parcel_id.

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 clearly states the tool retrieves a French cadastral parcel by its 14-character identifier and lists the returned fields (contenance, commune, closest road). This distinguishes it from siblings like get_french_building_permits or get_french_commune_facts, though the cryptic 'dont le jumeau porte tout le reste' weakens explicit differentiation.

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 implicitly tells the agent this is the surface-level parcel lookup and that a twin tool carries 'all the rest', and it explicitly notes the owner is not served. However, it never names the alternative tool or gives concrete conditions for when to prefer a sibling, leaving routing partially to inference.

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