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

With no annotations, the description carries the full burden, and it does add real context: each rate is tied to its legal basis (PMK 131/2024, UU 10/2020, PMK 97/2024 Lampiran I), which tells the agent the data is authoritative and static. However, it says nothing about the shape of the response, whether the dataset is exhaustive or versioned, or how a single rate is addressed.

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 front-loaded sentence naming the resource first, then the three categories with their decrees. Dense with legal references but each clause earns its place by tying a rate family to its regulation. No wasted preamble.

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 two-parameter read-only lookup with no annotations and no output schema, the description usefully previews what each category returns (rate level plus legal decree), which partly substitutes for the missing output schema. The gaps — result shape, how rate_code identifiers are formed — are minor and largely covered by the schema.

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 schema already documents both parameters, including the enum values and the 'omit for all' behavior. The description restates the category names and enriches them by explaining what each contains, but it says nothing about rate_code, so it adds partial value over the schema. Baseline 3 is appropriate.

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 a specific resource — Indonesian tax and duty rates — and enumerates the three scopes it covers (PPN, Bea Meterai, cukai hasil tembakau), which implicitly draws a boundary against income-tax siblings like get_pph21_ter and get_ptkp. It never names a verb ('returns'/'lists'), and it does not explicitly tell the agent how it differs from those siblings, so it falls short of 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 or when-not-to-use guidance, and no sibling is named as an alternative. The only usage signal is the implicit 'look here for statutory tax rates', which the agent must infer from the content list rather than from any stated condition.

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