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

Annotations are all false, providing no safety or side-effect hints, so the description carries the burden. It implies a read-only lookup by describing output (clock changes, UTC instant, offsets), but it does not explicitly state that no changes are made or mention any other behavioral traits such as auth or rate limits. This is adequate but not rich.

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 only: the first states the output and scope, the second gives a concrete use case. No filler or redundancy, and the core information 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?

For a simple 2-parameter tool with no output schema, the description adequately explains what is returned (UTC instant, offsets before/after) and the typical use. It doesn't specify whether multiple changes per year are returned together, but 'the clock changes' implies plural. Minor gap but not enough to hinder correct invocation.

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 covers both parameters (zone required, year optional) with descriptions. The description adds no extra parameter detail (e.g., zone format or year range). Per the coverage baseline, 3 is appropriate since the schema already carries the semantic weight.

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 identifies the resource (clock changes in a place for a year) and the output (UTC instant and offsets before/after). The use case ('check whether a recurring call moves') distinguishes it from sibling tools like convert_time and now, though it lacks an explicit verb like 'returns'.

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 phrase 'Use it to check whether a recurring call moves for one of you in March or October' provides a concrete, clear context for when to use the tool. It does not mention alternatives or when not to use it, but the guidance is specific enough for an agent to route correctly.

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