timezone_resolve

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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the description doesn't need to restate safety. It adds valuable behavioral context: the date parameter triggers historically-correct UTC offset calculation, and the credit cost is disclosed. This goes beyond the annotation baseline, though it stops short of describing exact response structure.

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?

Four sentences, each earning its place: purpose, usage, date behavior, credit cost, and alternative tool. No filler or redundancy. The most important information (what it does and when to use) is 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?

With no output schema, the description doesn't detail the return format, but the tool's complexity is low and annotations cover safety. It addresses purpose, usage, alternate tool, credit, and date-specific behavior. The only minor gap is not mentioning response fields (e.g., timezone name), but this is acceptable given the simplicity.

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 only 33% (date is documented in schema, latitude/longitude are bare numbers). The description compensates by explaining that passing the date yields a historically-correct UTC offset, which enriches the date parameter's meaning beyond the schema. Latitude/longitude are self-evident from the purpose, so no further elaboration is needed.

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 opens with 'Resolve the IANA timezone for a latitude/longitude pair' – a specific verb+resource that clearly defines the tool's purpose. It distinguishes itself from the sibling location_search by explicitly mentioning that location_search is the alternative when starting from a place name.

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?

Provides explicit usage context: 'Use when you have coordinates but need the timezone to interpret a local birth time.' It also names the alternative tool (location_search) and explains when to choose it instead, giving clear when-to-use and when-not-to-use guidance.

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