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

No annotations are provided, so the description carries the full transparency burden. It discloses the classification output, geolocation/network owner inclusion, and the behavior when `ip` is omitted. It does not explicitly mention read-only/non-destructive nature, but that is implied by the lookup verb. It adds useful context beyond the schema, though it omits rate limits or external API dependencies which are not critical.

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 concise sentences: the first states the core purpose and outputs, the second provides use cases and the default parameter behavior. No redundancy, fully front-loaded, every sentence earns its place.

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?

The tool is a single-parameter lookup with no output schema, but the description covers the essential context: what classification categories are returned, the additional fields (geolocation, network owner), use cases, and the default behavior. This is complete for a simple IP-classification 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?

With 100% schema coverage, the parameter is already well-documented. The description adds value by rephrasing the default behavior ('Omit `ip` to check the connection this MCP request came from') in a more operational way, reinforcing when to omit the parameter. This elevates it beyond the schema baseline of 3 to a 4.

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 clearly states the tool's function with a specific verb ('Classify') and resource ('an IP'), and enumerates classification categories (hosting/datacenter, open proxy, mobile-carrier) plus geolocation and network owner. This distinguishes it from sibling tools like ip_lookup or asn_lookup by focusing on traffic classification rather than generic IP details.

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 provides clear context for when to use the tool: 'Use it to decide whether traffic is likely a VPN, a cloud server or a real residential/mobile user — for fraud triage, abuse review, or checking whether your own VPN is being detected.' While alternatives are not explicitly named, the use cases are concrete and differentiate from simple IP lookups. It lacks explicit exclusions (e.g., 'use ip_lookup for general details'), hence not a 5.

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