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

Read-only and non-destructive behavior is already covered by annotations, but the description adds two pieces of information that annotations cannot convey: a cost of 10 credits and the partial-failure behavior where non-US IPs return null demographics rather than an error. The only gap is that it does not say whether a null-demographics response is still billed the full 10 credits.

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 well front-loaded — purpose first, then output contents, then the geographic limitation and cost as a parenthetical. The one inefficiency is the redundant 'IP Demographics: IP Demographics combines...' echo of the title, which occupies the opening clause without adding 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?

With a single fully documented parameter, an output schema present, and read-only annotations, the description supplies everything the agent needs: what the tool returns, which regions are covered, and what happens elsewhere. The only unresolved item is billing behavior for the null-demographics path, a minor gap for a one-parameter tool.

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%, and the 'ip' property already documents 'IPv4 or IPv6 address' with an example. The description adds only the phrase 'for any IP address', which conveys no additional syntax, formatting, or edge-case guidance beyond the schema. Baseline 3 is appropriate when the schema does the work.

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 states a specific operation: combine IP geolocation with Census demographic data (location, income, education, housing) for a given IP. That phrase distinguishes it in substance from IPLookup (geolocation only) and ZIPDemographics (ZIP input), though it never names either sibling explicitly, so an agent must infer the distinction from the 'based on the IP's geographic location' wording.

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 conditions on when the tool works and when it degrades: 'Demographics cover US ZIP codes; other locations return the location with demographics set to null.' That tells an agent up front that non-US IPs yield geographic data only. It stops short of naming alternatives (e.g., ZIPDemographics for a known ZIP), so it is strong context without explicit routing.

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