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

Annotations already declare readOnly, idempotent, non-destructive, closed-world behavior, so the safety profile is covered. The description adds meaningful traits on top: the content is dated and official-source, and it is advisory only (no liability or rate determination). It does not describe the response shape or whether guidance can be stale by jurisdiction.

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?

Two tight sentences: the first front-loads what the tool returns and for whom, the second gives timing and the scope exclusion. No wasted words.

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-only tool with no output schema, the description covers what it returns, when to call it, jurisdiction coverage, and its limits. Only the returned guidance format/details are left implicit, which is acceptable given the lack of an output schema.

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 0% and the schema merely constrains the field to a two-letter uppercase pattern. The description compensates by enumerating the accepted values (US, CA, GB, AU) and implying the country is optional by offering a general checklist, which the schema's zero required parameters corroborates.

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 concrete verb and resource ('Read dated official-source tax setup guidance') plus the exact jurisdictions covered (US, CA, GB, AU) and a no-country checklist variant. An agent can distinguish it from the sibling tax_profile_set, which writes setup rather than reading guidance.

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?

Gives explicit timing triggers: 'before tax setup' and 'whenever jurisdiction or service changes.' It also bounds scope with 'does not determine liability or a rate.' It does not explicitly name the alternative sibling (tax_profile_set) for actually persisting setup, so it stops short of full routing guidance.

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