Timezone Lookup

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

Annotations already indicate readOnlyHint=true, and description adds cost (1 credit), plan restrictions (works on free and paid), response structure, and constraints (lat/long together, lang paid-only). No contradictions. Adds significant behavioral detail beyond annotations.

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?

Description is comprehensive but well-structured: first sentence gives purpose, endpoint, plans, cost; second covers return structure; third details selector priority. It is not overly verbose for the complexity of 9 parameters, though could be slightly more condensed.

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 explains the return object ('{ time_zone } plus selector context') and lists fields. It covers important constraints like plan restrictions and parameter dependencies. Adequately complete for a tool with 9 optional parameters.

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 100%, providing parameter descriptions. The description adds value by specifying selector priority order, requiring lat and long together, and noting that non-English lang is paid-only. This enriches the semantic meaning for the agent.

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 'Read-only timezone lookup' and specifies the resource (timezone) and verb (lookup). It explicitly distinguishes from sibling convert_timezone by stating 'use convert_timezone for source-to-destination conversion.'

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?

Describes exactly when to use this tool: 'Use when the user asks for one place, IP, airport, UN/LOCODE, or IANA timezone current local time or metadata.' It also provides explicit alternative for conversion, and mentions selector priority for multiple parameters.

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