Get Hmrc Vat Liabilities

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

Annotations already declare the tool read-only, idempotent, and non-destructive. The description adds valuable context beyond this: the data comes directly from HMRC MTD and requires an active HMRC MTD connection, which is a useful precondition for the agent to know.

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 three focused sentences with no filler: it states what the tool reads, when to use it, and what prerequisite exists. Each sentence provides distinct value and the core purpose is front-loaded.

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?

Given the tool's low complexity, optional parameters fully covered by the schema, and rich annotations, the description covers all essential operational context: purpose, usage examples, source, and required integration. Nothing critical is missing for an agent to decide whether to call it.

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 both 'from' and 'to' parameters are already documented with their formats and defaults. The description does not add new parameter-level meaning beyond what the schema provides, so the baseline score of 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 verb ('Read') and resource ('company's VAT liabilities') and clarifies what those liabilities are: amounts HMRC says are owed and when they are due. This clearly separates it from related tools like VAT payments or obligations by focusing on outstanding amounts owed.

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 explicitly tells the agent when to use this tool, citing natural user phrasings like 'how much VAT do I owe HMRC' and 'what's outstanding on my VAT account'. It does not mention exclusion criteria or name alternative tools, but the usage context is clear.

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