Reverse geocode a point

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

The description goes well beyond the readOnlyHint annotation by explaining the degraded divisions-only path, the source identifier 'divisions_only', the reason addresses may be missing, and the structured error return instead of an exception. This is rich, honest behavioral disclosure.

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?

Two tightly packed sentences convey the core operation, the degraded mode, the cause, and the error behavior. No filler or redundancy; the most important output semantics are front-loaded.

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?

The tool is simple in inputs, has an output schema to cover result shape, and annotations to cover safety. The description adds exactly the missing context: the expected degraded path and error handling. Nothing critical is left unexplained.

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?

With 0% schema description coverage, the description was responsible for explaining lat/lon semantics, but it only refers to a 'Point' generically. It does not state coordinate format, bounds, or how the point maps to the parameters, leaving the agent with only the property names 'lat' and 'lon'.

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 a specific operation: converting a geographic point into the nearest address and its containing division chain. It distinguishes this from forward geocoding and batch reverse geocoding through the 'Point -> ...' framing and the tool name/title.

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 usage context is implied: it handles a single point and returns address plus divisions. However, it never explicitly says when to prefer this over reverse_geocode_batch, geocode, or address_at, and it names no alternatives or exclusion conditions.

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