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

Annotations already declare readOnlyHint and openWorldHint, so the read-only nature is covered. The description provides additional behavioral details by stating specific return fields (country, city, ISP), which is useful given the absence of an output schema. It does not disclose potential edge cases, but the annotation coverage lowers the burden.

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 extremely concise: one sentence for purpose and a structured Args section for the parameter. Every element serves a purpose with no redundant text, making it both efficient and easy to scan.

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 simple read-only, single-parameter tool, the description covers the essential aspects: purpose, parameter format, and output fields. It lacks error/edge-case handling (e.g., invalid IPs), but given the tool's simplicity and the presence of annotations, this is not a major gap.

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 only specifies ip as a string with no format, and schema description coverage is 0%. The description compensates by labeling the parameter as an IP address and providing an explicit format example ('8.8.8.8'). This fully clarifies the parameter's meaning and expected input.

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 uses a specific verb 'look up' with a clear resource 'IP address' and explicitly lists the returned fields (country, city, ISP). It distinguishes itself from sibling tools like dns_lookup, ssl_check, and whois_lookup, all of which serve different purposes.

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 purpose clearly implies when to use the tool: when geolocation data for an IP address is needed. Although it doesn't explicitly name alternatives or exclusions, the context is clear enough and sibling tools are distinct in their functionality.

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