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

Annotations already declare readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. With no output schema, the description earns credit for enumerating the response fields and the status vocabulary (mandatory, phased, voluntary, pilot, planned, unclear, none_found), but it says nothing about coverage limits, whether a 'none_found' result is an error, or data freshness.

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?

One front-loaded sentence with no filler; the enumerated field list is dense but each item maps to a meaningful part of the returned record. It would be stronger opening with an explicit verb rather than a bare noun phrase.

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 one-parameter lookup with no output schema, describing the returned fields is the right instinct and covers a lot. It falls short on the operational side: no indication of which countries are covered, how missing or ambiguous jurisdictions are reported, or how the phased dates are formatted.

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% with a single well-documented 'country' parameter including ISO 3166-1 alpha-2 examples, so the schema does the work. The description adds nothing about the parameter, so the baseline of 3 applies.

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 is a noun phrase enumerating the fields of the returned record ('system... tax authority, status... model... dated phases... legal basis... integrators') rather than stating an action. It is clear what data the tool surfaces, which distinguishes it somewhat from get_vat or get_country_profile, but there is no explicit verb such as 'retrieve' and no direct contrast with those siblings.

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?

There is no guidance on when to choose this tool over get_vat, get_country_profile, or get_filing_deadlines, and no stated preconditions. The only implicit cue is that the record is scoped to e-invoicing/fiscalisation, leaving the agent to infer the routing itself.

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