today

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

With no annotations, the description carries the full transparency burden. It usefully discloses the timezone (UTC-5) and that the value is intentionally pinned to 'today.' But it does not explain what happens on non-business days, which rate is returned, or other edge-case behavior, leaving some important behavior implicit.

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 short, front-loaded, and free of filler. The first sentence states what the tool returns and the second justifies its existence; every part earns its place.

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 zero-argument utility with an output schema available, the description is nearly complete: it provides the location/timezone, the value returned, and the reason to use it. It could more explicitly state the rate type or non-trading-day handling, but those are minor given the sibling context.

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, so parameter documentation is not needed and baseline 4 applies. Nothing about parameter meaning is missing.

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 what the tool provides: today's date in Colombia (UTC-5) and today's rate. It also hints at differentiation by noting that other tools default to 'today.' However, it lacks a direct action verb and never names the rate type explicitly, so it is clear but not maximally precise.

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 rationale explains why this tool exists: models often get 'today' wrong, and other tools default to it. This gives an agent clear context for when to call it instead of reasoning about the current date. It does not explicitly list exclusions or alternatives, but the sibling names and the default-today note provide enough guidance.

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