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

Goes well beyond the readOnly/openWorld annotations: it discloses that IP addresses are refused, that server/edge-node location is ignored, that it costs one to four upstream requests, and it spells out the quota model (25 lookups/day open, request-metered with a key). These are exactly the operational facts an agent needs before calling.

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?

Front-loaded with the purpose and the key constraint (never uses server location, refuses IPs), and dense rather than padded. The quota and billing sentences are long but each carries decision-relevant information, though the paragraph could be split for 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 one-parameter, read-only tool with annotations covering safety, the description covers cost, auth, and input restrictions thoroughly. The one gap is that with no output schema it never says what a successful result looks like (jurisdiction code vs. name), leaving the return value underspecified.

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% and the single parameter is fully documented in the schema, so the baseline of 3 applies. The description reinforces the IP-rejection rule but adds little syntax or format detail beyond what the schema already states.

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 and resource ('mapping from a domain to the jurisdiction whose law governs its OPERATOR') and scopes it clearly as a derivation step for the other tools. The contrast with sibling tools (feeding into them rather than being one) makes it distinguishable without opening the schema.

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?

Explicitly says 'call this only to derive a jurisdiction from a domain rather than declaring one', which both states the correct condition and excludes the alternative path. It also tells the agent this call sits outside a lint's five-request budget, removing a real usage ambiguity.

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