get_sales_today

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

With no annotations, the description carries the full burden. It adds a valuable behavioral detail about using the local timezone for the day boundary and clarifies that the output includes a merchant rank, which is not obvious from the name alone. It does not disclose rate limits or side effects, but as a read-only 'get' operation, that is acceptable.

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 concise sentences effectively front-load the main purpose and then add a relevant timezone note. There is no redundant or filler content, making it highly efficient.

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 simple tool with one optional parameter and no output schema, the description adequately explains what the tool does, what it returns, and the relevant timezone behavior. It is complete enough for an agent to understand the tool's function and invoke 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?

The schema already provides a complete description for the platform parameter, including valid values ('fitbit' or 'garmin') and behavior when omitted. The tool description adds no additional parameter semantics beyond what the schema states, so the baseline of 3 is appropriate.

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 retrieves today's sales, specifying the metrics returned (number of purchases, revenue amount, rank). It distinguishes from siblings like get_sales_yesterday by explicitly scoping to today and noting the local timezone boundary.

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?

Provides clear context that this tool is for today's sales and uses the local timezone. While it doesn't explicitly name alternatives or exclusions, the 'today' scope and sibling names like get_sales_yesterday make the usage context clear without needing further guidance.

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