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

With no annotations, the description carries full burden. It states the tool computes SDLT, implying determinism and safety, but does not disclose behavioral details such as whether external data is fetched or if there are rate limits. For a calculator, the behavior is somewhat implied, but more transparency would help.

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 two sentences, efficiently stating purpose, inputs, outputs, and a reference. It is front-loaded with essential info. However, the inaccuracy about the second-home flag detracts from its usefulness.

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?

The description lacks context about SDLT's complexity (e.g., tax bands, surcharges). Given the output schema exists, return values are covered, but the tool's behavior regarding missing second-home parameter is a major gap. The description should clarify what the tool computes and what parameters are actually available.

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 schema has 100% coverage for parameters 'price' and 'first_time_buyer', but the description mentions a 'second-home flag' that is not in the schema. This is misleading and constitutes a factual error. The description adds no value beyond the schema and actually introduces confusion.

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 clearly states the tool computes UK Stamp Duty Land Tax for home buyers, specifying inputs and outputs. It differentiates itself by referencing list_bundles for related calculators. The verb 'Compute' and resource 'UK Stamp Duty Land Tax' are specific, making the purpose unambiguous.

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 says 'Use for UK home buyers,' indicating when to use. It also directs to list_bundles for related 'finance-uk' calculators, providing an alternative. However, it does not explicitly state when not to use or exclude scenarios like non-UK buyers.

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