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

Annotations already declare the tool as read-only, idempotent, non-destructive, and open-world, so the safety profile is covered. The description adds valuable scope details: exactly what is returned (area, commune, nearest road) and what is deliberately excluded (owner identity), which helps the agent understand the data boundaries.

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 two sentences and front-loads the core operation: retrieving a parcel by its identifier. It is dense but efficient, though the reference to a 'jumeau' without naming it slightly reduces immediate clarity.

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, read-only lookup with no output schema and clear annotations, the description covers what the tool returns and its main limitation regarding owner data. Naming the concrete alternative for ownership information would make it fully complete.

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%, so the input schema already documents the single parcel_id parameter with its regex pattern and example. The description goes further by breaking the 14-character identifier into its INSEE code, prefix, section, and number components, adding semantic meaning beyond the 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 that the tool returns a French cadastral parcel by its 14-character identifier, including its area, commune, and nearest road. This is a clear verb-resource pairing, but it does not name the sibling tools it contrasts with, referring only to an unnamed 'jumeau' (twin).

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 implies when to use the tool (to get parcel attributes by ID) and when not to use it for ownership information, noting that legal-entity owners are found in the road twin while individuals are not found at all. However, it never names or directly points to the alternative sibling tools, leaving routing implicit.

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