today

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

No annotations are provided, so the description carries the full burden. It discloses that the tool returns a UTC date and lists the returned fields (iso_date, iso_datetime, year, etc.). It does not mention any side effects, but given the read-only nature, this is sufficient. The behavioral context is well-covered.

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 concise, with the core purpose in the first sentence and no unnecessary words. It includes a bulleted list of return fields, which is efficient. Slightly front-loaded with important usage advice. Could be marginally tighter, but still effective.

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?

Given the tool's simplicity (no parameters, no output schema), the description fully covers what the tool does, when to use it, and what it returns. It addresses potential confusion about temporal anchoring. The sibling tools are diverse, so no risk of overlap.

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 tool has zero parameters, and the input schema is empty. Per guidelines, baseline is 4. The description adds value beyond the schema by explaining the return format and usage context, making it informative.

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 the tool returns the server's current date in UTC, using a specific verb ('Return') and resource ('SERVER'S CURRENT DATE'). It distinguishes from sibling tools which are focused on fetching, searching, or acting, making the tool's unique role obvious.

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 explicitly instructs to call this tool first when the user mentions temporal phrases like 'today' or 'this quarter', and warns that the training data cutoff is unreliable. This provides clear when-to-use guidance and distinguishes it from alternatives.

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