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

Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false and destructiveHint=false, so the safety profile is covered. The description adds real context beyond that: it takes no arguments, it returns only *live* jurisdiction values and a *sample* of topics (not exhaustive), and it includes defaults. That last detail matters to an agent deciding whether the list is authoritative.

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 short sentences, front-loaded with the resource and payoff, then the usage rule. No repetition of the title and no filler; every clause carries information.

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?

An output schema exists, so the description need not explain return shape, and it still names the facet categories and the 'defaults' it returns. For a zero-argument read-only helper this is complete coverage of what an agent needs to select and call it.

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?

With zero parameters the baseline is 4, and the description reinforces it with 'Takes no arguments,' which matches the empty schema. No further parameter semantics exist to document, so there is nothing more the description could add.

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 ('lists the values you can filter on') and enumerates the facet dimensions it covers (jurisdictions, domains, roles, rule kinds, statuses, tax years, topics). It also positions itself explicitly as a helper for the sibling tool search_rules, so an agent can distinguish it from list_jurisdictions and the other list_* tools without opening schemas.

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 an explicit trigger ('Use it when unsure of a filter value rather than guessing') and names the tool it feeds into (search_rules). The when-not case is implied and unambiguous: if you already know the filter value, go straight to search_rules.

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