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

With no annotations provided, the description carries the full burden of disclosure. It reveals important behavioral traits: the basket is fixed, equally weighted, never rebalanced, and reference prices are immutable as of the base date. This goes beyond a bare read operation, though it does not mention potential errors or side effects, which are minimal for a simple retrieval.

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?

The description is compact, consisting of two sentences, but it packs all essential information: the basket composition, fixed nature, reference and current prices, price movements, and the additional unit codes. There is no filler, and the structure is logical, starting with the main action.

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 tool with no parameters and no output schema, the description fully specifies what the response will contain: nine components, reference prices, current prices, price changes, and the list of unit codes for ieunit_convert. It also explains the basket's immutable design, making the tool self-contained and easily understood.

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?

The tool has no parameters and the input schema is an empty object. Since there are no parameters, the description need not add any parameter semantics, and the baseline for a zero-parameter tool is 4. The description adds no irrelevant parameter information.

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 opens with a specific verb and resource: 'Get the composition of the ieUnit basket,' and immediately enumerates the exact contents (nine fixed components, reference prices, current prices, price movements). It clearly distinguishes this from sibling tools like ieunit_convert or ieunit_compare by focusing on basket composition rather than conversion or comparison.

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 when to use the tool—whenever basket composition or reference prices are needed—but it does not explicitly say when to use it versus alternatives or provide any exclusions. The note about returning unit codes accepted by ieunit_convert gives a practical linkage but falls short of explicit guidance.

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