vat_rates_list

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

Annotations already declare readOnly, idempotent, closed-world, and non-destructive, so the safety profile is covered. The description goes beyond them by disclosing the sort order and enumerating exactly which fields are returned (percentage, label, e-Factura category code, default flag), which is meaningful because no output schema exists. It does not mention permission requirements or whether the list is user-editable, so it stops just short of a 5.

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 first sentence front-loads the action and scope, then the return fields, then domain context; each sentence is purposeful. The final sentence on common Romanian rates is supplementary rather than essential to invocation, but it is short and genuinely useful for sanity-checking values, so it does not feel like padding.

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 single-optional-parameter read tool with no output schema and full annotation coverage, the description supplies what the schema and annotations cannot: the returned fields, their ordering, and a reference set of expected rate values. An agent has everything needed to select and invoke it 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?

There is a single optional parameter with 100% schema description coverage, so the schema already explains the companyId override, establishing a baseline of 3. The description reinforces the default ('active company') but adds no format, validation, or failure semantics beyond what the schema states.

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 uses a clear verb ('List all') and a specific resource ('VAT rates configured for the active company') and scopes the result to the active company with a defined ordering. It is easy to distinguish from vat_rates_create/update/delete, though it never names a sibling such as vat_category_codes_list, so the differentiation is implicit rather than explicit.

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?

Usage is only implied: 'configured for the active company' tells the agent the context, but there is no statement of when to prefer this tool over vat_category_codes_list, nor when to pass companyId instead of relying on the active company. An agent can infer this is the read path for VAT rates, but nothing is explicit.

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