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

With no annotations, the description itself carries the behavioral burden. It discloses the key trait: the value is the actual live current time, not a training-cutoff guess. While it doesn't explicitly state 'no side effects' or mention latency, the tool is a simple getter and the most important behavioral fact is prominently addressed.

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?

A single, front-loaded sentence that states the action first and adds a concise explanatory clause. Every word earns its place; there is no filler or repetition of schema information.

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 low-complexity tool with a complete input schema and an output schema present, the description covers the essential context: what it returns and why it exists. There are no missing details that would prevent an agent from invoking it correctly.

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 description coverage is 100%, so the parameters are fully documented in structured data. The description adds no information about the 'format' or 'timezone' parameters, which is acceptable given the schema's completeness, but it does not enhance parameter understanding beyond that.

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 a specific verb ('Returns') and resource ('actual current date/time'), leaving no ambiguity about what the tool does. It even distinguishes the tool's core purpose from an LLM's inherent limitation, which is valuable context even without siblings.

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 gives clear context for when to use the tool: whenever a live clock is needed because an LLM cannot know the current time. It doesn't mention alternatives, but there are none in the sibling list, so no exclusion is needed. The reasoning is explicit enough to guide an agent.

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