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

With no annotations provided, the description carries the full disclosure burden, and it delivers: it states that value is rounded up to the next €100, enumerates the four outputs, discloses the 20% provisional payment rule, and notes that missing inputs fall back to documented defaults. This is substantial behavioral context for a pure calculation tool, though it stops short of describing the response format or error behavior.

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, action-first, and organized as a clear list of outputs followed by a compact defaults note. It earns a 4 rather than 5 because of the redundant 'calculator calculator' typo, which is a minor polish defect in an otherwise tightly written definition.

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 simple two-parameter tool with a fully documented schema and no output schema, the description is reasonably complete: it names the inputs' roles, enumerates all outputs, and discloses key calculation behaviors. The main gaps are the absence of an explicit response shape and the lack of guidance on which sibling to use for related but different needs.

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 baseline is 3; both 'basis' and 'value' are already well documented in the schema. The description adds a small amount of parameter-relevant context by stating that missing inputs fall back to documented defaults and by implying the rounding rule applies to the value, but it does not deeply expand parameter meaning beyond what the schema provides.

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 verb ('Run') and a specific resource (the Malta stamp duty calculator), and it lists the computed outputs (value taken for duty, duty payable, effective rate, provisional payment), which makes the purpose concrete. However, it does not explicitly differentiate itself from the sibling calculator_describe; the distinction is implied by the word 'Run' versus 'describe' rather than stated.

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 this tool is the one that executes the stamp duty calculation, and the sibling names (calculator_describe, enquiry_describe, enquiry_fields, submit_enquiry) suggest there are alternatives for describing or submitting enquiries. However, there is no explicit when-to-use versus when-not-to-use guidance, and no sibling is named as an alternative.

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