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

Annotations already declare readOnlyHint=true, so the safe-read profile is covered. The description adds pagination behavior ('cursor paged: pass the reply's next_args as the next call's arguments') and the token requirement, which are real traits beyond the annotations.

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?

Three dense sentences with the returned fields, filters, token/alternative note, pagination, and endpoint all front-loaded. No filler; every clause earns its place.

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 read-only list tool with no output schema, the description enumerates the returned fields and explains cursor pagination, so an agent has everything needed to call and iterate correctly.

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 coverage is 100%, so the baseline is 3. The description adds useful semantics by clarifying that name is a partial match and percentage is exact, and by tying the next_args cursor value to the after/before parameters.

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?

States a specific verb+resource (list VAT rates) and enumerates the returned fields (ids, name, percentage, reverse-charge flag). It also distinguishes itself from the sibling smartbill_list_taxes by noting the token difference, so an agent can tell them apart.

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?

Explicitly names the alternative (smartbill_list_taxes) and the condition that differentiates it (no V3 token needed), and states the filter modes. The routing rule is implied rather than spelled out as 'use X when you lack the token', so it falls just short of a 5.

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