Get today's date

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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds genuinely new behavioral context: the value is computed in the user's time zone, and it enumerates the returned fields, telling the agent this is a stable per-day anchor to compute relative dates from.

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, zero filler, and the return shape is front-loaded before the usage trigger. Every clause carries information the agent needs.

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?

With an output schema present, the description needn't explain return structure, and it still summarizes it in one clause. Zero parameters, full annotation coverage, and no missing prerequisites make this complete for a trivial read 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 tool takes zero parameters, so there is nothing for the description to disambiguate. That matches the baseline of 4 for parameter-free tools.

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?

States a specific verb and resource and pins down the exact payload: "Today's date in the user's time zone: date (YYYY-MM-DD), timezone and weekday." The word "today" and the timezone scoping distinguish it from the sibling get_day, which an agent can infer handles arbitrary dates.

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?

Explicitly names the trigger phrases ("today, yesterday, tomorrow, this week or a weekday") and even instructs the agent to "count from it," which is actionable usage context. It does not name the alternative (get_day) for non-today dates or state any exclusions, so it falls short of a full when/when-not treatment.

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