datetime_now

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

With no annotations, description is the sole source of behavioral info. It states the tool returns current time but does not disclose output format, return type, or timezone validation. The mention of 'various format options' is misleading since no format parameter exists.

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 sentence and front-loads the core purpose. It is concise, though it sacrifices necessary detail for brevity, which is acceptable given the short form.

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 tool with no output schema and no annotations, the description should explain return format, timezone handling, and format options. It only gives a high-level statement, leaving the agent without enough information to predict behavior.

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 schema already covers the timezone parameter with examples, so the description adds little value. The reference to 'format options' implies parameters that do not exist in the schema, creating confusion rather than clarity.

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 tool as retrieving the current time for any timezone, which distinguishes it from sibling tools like datetime_diff. However, 'various format options' is vague and unsubstantiated by the schema, leaving ambiguity about output behavior.

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?

No guidance is provided on when to use this tool versus alternatives, and no exclusions or prerequisites are mentioned. The description implies usage but does not explicitly state it.

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