Current Time

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It transparently states that the tool returns server time (not local/client time), accepts an IANA timezone, and defaults to UTC. It also implies a read-only operation with no side effects. While it doesn't detail error handling or output format, the core behavior is clearly disclosed.

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 a single, well-structured sentence that front-loads the action ('Returns the current server time') and includes necessary context (IANA timezone, default UTC). Every word is informative, and there is no redundant or filler content.

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?

This is a low-complexity tool with one optional parameter and an output schema present. The description adequately covers the tool's purpose and input behavior. Since an output schema exists, the description does not need to explain return values. The description is complete enough for an agent to correctly select and invoke the tool.

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 input schema provides 100% coverage of the 'timezone' parameter, including its IANA format and default value. The description adds example timezone names, but this information is already in the schema description. Therefore, the description adds minimal semantic value beyond the structured schema, warranting the baseline score of 3.

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 what the tool does: 'Returns the current server time in the requested IANA timezone.' It uses a specific verb and resource, and provides concrete examples of timezone values. This distinguishes it from sibling tools like echo, calculate, or random_number, which have entirely 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 description implies usage: use this when you need the current server time, optionally in a specific timezone. However, it does not explicitly mention alternatives or when not to use it compared to other tools. There is no direct guidance on tool selection relative to siblings, so it falls to 'implied usage' rather than clear contextual differentiation.

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