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

Annotations already declare this as a read-only, idempotent, non-destructive, closed-world operation, so safety is covered structurally. The description adds genuinely behavioral context the annotations cannot: v2 vs v1 precision differences and the ±10 m / ±20 m accuracy envelope, telling the agent how much to trust the result.

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 dense sentences, front-loaded with the core transform before the format/precision qualifiers. Nothing is redundant and every clause carries information.

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?

With no output schema, the description carries return-value burden and does state that lat/lng is produced (cell centre for v2), but it never names the returned fields or mentions error behavior for malformed codes. Adequate for a single-parameter deterministic lookup, with a small remaining gap.

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 100% schema coverage plus an example, the baseline is 3, but the description goes further by specifying that dashes are optional and that a leading country calling code such as '082-' is ignored — parsing rules the schema's bare string does not convey.

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?

States a specific verb and resource ('Turn a WIA Pin Code ... into latitude/longitude') and pins down the exact accepted code variants (12-digit v2, 9-digit v1), which cleanly separates it from the generate_* and encode siblings.

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 its use case (converting a code you already hold into coordinates) but never states when to prefer it over pin_code_encode, pin_code_nearby, or get_wia_code_info, nor any exclusions or prerequisites. Usage is inferable but not guided.

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