reverse_geocode

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

The description adds critical behavioral context beyond annotations: coverage area and null return for out-of-region coordinates. Annotations already mark the tool as read-only, idempotent, etc., and the description does not contradict them. It clarifies that null is a valid result, not an error.

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 long, each earning its place. The first states the core function, the second provides crucial constraints and behavior. No redundant words.

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?

Given there is no output schema, the description explains the return behavior for invalid input (null) and implies a valid address for valid inputs. It does not detail the address format, but overall it is sufficient for an agent to use correctly. Minor gap in output structure description.

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% with clear descriptions for lon and lat. The description adds no additional semantic detail beyond restating that they are GPS coordinates. Baseline score of 3 is appropriate as no further value is added.

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 it is a reverse geocode that returns the nearest address from GPS coordinates. It also specifies the source and coverage area, distinguishing it from siblings like geocode_adresse.

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 explicitly mentions coverage limited to France métropolitaine + DOM, and that coordinates outside this area or in the sea return null (not an error). This guides agents on when the tool is appropriate. However, it does not explicitly contrast with sibling tools like geocode_adresse for forward geocoding.

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