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

Annotations already declare readOnlyHint and destructiveHint, but the description adds meaningful behavioral context beyond those: establishment is decided by the registry/regulator and executed via licensed local partners, tax outcomes follow residence, and the output is explicitly information, not legal or tax advice. No contradiction with annotations.

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 description is dense and front-loaded with the core topic, and every clause adds substantive coverage detail. However, it is a single very long sentence with a heavy enumeration, which would be easier to parse if structured into bullets; the content is earned but the format taxes readability.

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 read-only reference tool with one optional parameter and an output schema, the description covers scope, invocation mode, jurisdictional coverage, establishment caveats, and tax-residence nuance. Nothing an agent needs to decide whether to call it, and how to call it correctly, is missing.

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?

The schema describes cc as an ISO alpha-2 code, and the description adds the essential behavioral semantics: passing cc targets one jurisdiction, while omitting it returns the covered list. This goes beyond the schema's field description and resolves the key ambiguity of an optional parameter.

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 identifies a specific resource—foundation and trust rules—and enumerates the exact topics covered, from legal form existence to UBO visibility. It also distinguishes itself from shortlist siblings by framing this as the deep-dive layer ('Deepens the charity and trust jurisdiction shortlists...'), so an agent can tell it apart from find_trust_jurisdictions or find_charity_jurisdictions.

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?

The description gives clear invocation guidance: 'Pass cc for one jurisdiction; omit for the covered list.' It also positions the tool contextually as the deep-dive successor to shortlist tools. However, it does not explicitly name alternative tools or state when not to use it, so the guidance is strong but not fully exclusionary.

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