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

Annotations already establish readOnly, idempotent, non-destructive and closed-world, so the safety profile is covered. The description adds genuinely new behavioral context beyond them: availability is gated by plan, with the tax parts on the Compliance plan and, for countries in its country pack, on Pro. It does not say what happens for an unsupported country code.

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?

A single front-loaded sentence where the resource is stated first and the payload is enumerated after the colon. It is dense but every clause names real content; only the parenthetical entitlement note is slightly tacked-on.

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?

With one required parameter, rich annotations and no output schema, the description carries the return-value burden and largely discharges it by enumerating the data sections returned. It stops short of describing the response shape or how missing/unsupported countries are reported.

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%: the single 'country' parameter already documents the ISO 3166-1 alpha-2 format, the regex pattern and examples (KE, NG, ZA, CI, EG). The description adds no further meaning about the parameter, so the baseline 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?

States a specific verb+resource ('All compliance reference data for one country') and enumerates the exact payload: holiday rules, announcement authority, VAT, withholding tax, tax ID format, filing deadlines and sources. This implicitly distinguishes it as an aggregate from siblings like get_vat, get_public_holidays and get_filing_deadlines, though it never names them as alternatives.

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: an agent can infer this is the one-shot country overview versus the topic-specific siblings, but the description never says 'use this instead of calling get_vat/get_public_holidays separately' or when a narrower tool is preferable. No prerequisites or exclusions are given.

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