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

Annotations already declare readOnly/idempotent/closed-world, so the safety profile is covered. The description adds real context beyond that: the implicit timezone (America/New_York) when from_date is omitted, the inclusive start boundary, and the fact the default date is echoed back in the response.

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, no filler, and the core capability is front-loaded ahead of the default-behavior caveat. Every clause carries information an 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 no output schema, the description carries the return-value burden and does so: each holiday's observed date and the number of calendar days away. Combined with the timezone and inclusive-boundary notes, an agent has everything needed to call and interpret this 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?

Schema coverage is 100%, so both parameters are already documented, including the 1–11 count range and the YYYY-MM-DD format. The description largely restates those bounds; the only marginal addition is the documented default of 1 and the fallback timezone behavior, which the schema does not state.

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 ('find') and resource ('next ... U.S. federal holidays') plus the exact scope rule: observed on or after a date, up to eleven results. This cleanly separates it from the sibling list_federal_holidays, which enumerates rather than picking the upcoming ones from a start date.

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?

It explains the default path ('Without from_date it starts from today's date in America/New_York and says which date it used'), which tells the agent the no-arg case works. It never names an alternative sibling or states when not to use this tool, so usage is implied rather than directed.

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