timezone.lookup

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

With no annotations, the description must disclose behavior. It explains the methodology: 'Polygon lookup against a CC0 timezone boundary index + runtime tzdata for current transition rules.' It also lists output components. However, it does not mention limitations, performance, or error handling.

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 sentences clearly state purpose and methodology. No redundant information. Efficient and front-loaded.

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?

No output schema, so description must explain return values. It lists all output fields. Methodology context adds completeness. Could be improved by mentioning output structure or error cases, but sufficient for typical use.

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 33% (only 'at' has a description). The description adds context for 'at' (optional, defaults to now) but does not elaborate on lat/lon beyond 'coordinate'. Schema includes min/max constraints for lat/lon, so description adds minimal value.

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?

Description clearly states 'Resolve a coordinate to its IANA timezone, current UTC offset, local wall time, DST status, and short abbreviation.' It specifies the verb and resource, and distinguishes from sibling tools by focusing on timezone resolution.

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?

No explicit when-to-use or alternatives are provided. The description implies usage for coordinate-to-timezone lookups, but lacks guidance on prerequisites or edge cases. Sibling tools include other lookup functions, but none directly competing.

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