ip_info

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

With no annotations provided, the description carries the full burden and delivers thoroughly. It discloses that the tool reflects the MCP server's egress IP (not the end user's), states it is read-only, requires no API key, and is rate-limited. All critical behavioral traits are explicitly covered.

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 two sentences long, front-loads the key information, and every sentence adds value. No unnecessary words or repetition. Highly efficient.

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?

Given no output schema, the description fully compensates by listing all types of returned information (address, ISP, ASN, geolocation, heuristics). It also covers scope (server's IP vs user's IP), safety (read-only), authentication (no key), and limits (rate-limited). For a zero-parameter tool, this is complete and leaves no gaps.

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 tool has zero parameters and schema coverage is 100%. The description explains it takes no input, which adds value by confirming the tool is input-free. Baseline 4 is appropriate since there is nothing to add beyond that.

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 reports information about the caller's own public IP, listing specific data points (IPv4/IPv6, ISP, ASN, geolocation, proxy/VPN heuristics). It distinguishes from siblings like asn_lookup by noting that ip_info reflects the server's egress IP, not a specific known IP.

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 explicitly says when to use (discover server's outbound IP, test connectivity) and when not (to inspect a specific known IP). It names two alternative tools (asn_lookup, reverse_dns) for the latter case. Provides clear decision guidance.

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