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

With no annotations provided, the description carries the full burden. It clearly states what the tool returns (frequency, deadlines, retention, risk), which implies a read-only informational behavior, but it does not explicitly declare its non-mutating nature or any limitations. No contradictions are present, and the description is adequate for this straightforward reference 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?

The description is compact and well-organized: a single-sentence purpose, a structured parameter list, and a return summary. Every element earns its place, with no filler or redundancy. The key information 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?

For a simple one-parameter tool with an output schema, the description covers the essential inputs and high-level outputs. It does not explain exact return formats, but the output schema likely handles that. It could explicitly state that the tool is a read-only reference, but this is a minor gap given the tool's simplicity.

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 0%, so the description must compensate. It does so by explicitly enumerating the allowed values for 'market' (UK, EU, US) and explaining it is the target market. This adds crucial meaning beyond the bare string type in the schema.

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 provides a filing obligation calendar covering frequency, deadline cadence, record retention, and late risk for UK/EU/US. It distinguishes itself from siblings (us_sales_tax_nexus and vat_registration_guide) by focusing on ongoing filing obligations rather than nexus or registration, though it does not explicitly name them.

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 via the 'market' parameter and the explicit return topics, but it does not explicitly compare with siblings or state when not to use it. The intended scenario is inferable, but there is no explicit routing or exclusion guidance.

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