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

With no annotations, the description carries the full burden. It usefully discloses the data source (Kepmen ESDM 218.K/MG.01/MEM.M/2022) and the unit ('per litre'), but says nothing about whether this is a single current price or a time series, nor about read-only/public-access characteristics. Adequate but incomplete for a zero-annotation tool.

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 tight sentences with zero filler; the scope limitation that most affects agent selection is front-loaded in the first clause. Every sentence earns its place.

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 lookup with no output schema and no annotations, the description covers unit, source regulation and inclusion scope. It leaves a meaningful ambiguity unresolved though: whether the returned price is a single latest value or a series, especially given sibling tools that split 'latest' from 'series' for food prices.

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% and the single enum parameter is already fully documented in the schema, so the baseline is 3. The description contributes the local-language mapping (Solar, minyak tanah, RON 90), which partially bridges to the enum values kerosene/gas_oil/ron90, but the schema already labels gas_oil as 'Solar'.

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 exact resource (retail price per litre of subsidised/special-assignment fuels) and enumerates the covered fuels, so an agent can tell it apart from neighbours like get_het_prices or get_ojol_tariffs. It omits an explicit verb and never names a sibling it should be preferred over, 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?

Scope is defined negatively ('Non-subsidised fuels are not included'), which implies when the tool applies, but there is no explicit when-to-use statement, no prerequisites, and no named alternative for non-subsidised fuel queries. Usage must be inferred from the scope clause rather than read directly.

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