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

No annotations are supplied, so the description carries the full behavioral burden. The plural 'Postal codes' usefully signals that a single kelurahan/desa may map to more than one code, and the operation is clearly a read. But it says nothing about permissions, empty results for an unmatched code, or whether the code must be resolved via get_wilayah first.

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?

A single tight sentence with no filler and the key scoping information ('one kelurahan or desa') front-loaded. It is a noun fragment rather than a full statement of action, which is a minor stylistic weakness but costs no 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 one-parameter, annotation-free lookup with no output schema this is minimally adequate: the agent can call it. It is incomplete on the two things that actually matter here — the relationship to reverse_postal_code and get_wilayah, and the shape of the result set.

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%: the single wilayah_code parameter is documented in the schema as a 'Kemendagri wilayah code' with a regex pattern. The description only restates that the input is a wilayah code, adding no format, prefix, or hierarchy detail beyond the schema, so the baseline 3 applies.

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 names the resource (postal codes) and the exact granularity (one kelurahan or desa) plus the input selector (wilayah code), so the agent knows precisely what comes back. It does not name or contrast with the obvious sibling reverse_postal_code, which is the only thing keeping it from a 5.

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?

There is no when-to-use guidance, no prerequisites, and no mention of the reverse_postal_code alternative for going the other direction (postal code -> area). Usage is only weakly implied by 'by its wilayah code'.

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