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

Annotations already cover read-only, idempotent, non-destructive and closed-world behavior, yet the description still adds real value: the idempotent no-op condition, the error on unknown calendar ids, and the scope limitation that it does not adjudicate filing timeliness. It does not restate anything the annotations contradict.

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?

Four short sentences, front-loaded with the core behavior, then scoping caveats, then the default-calendar rule. No filler and nothing buried.

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, a complete parameter schema, and full annotations, the description only needs to supply behavioral and scoping context — which it does via the no-op rule, the unknown-id error, the calendar default, and the explicit non-timeliness disclaimer.

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 description coverage is 100% and both enums are documented in the schema, so the schema carries the parameter burden. The description only restates the calendar default and the direction semantics, which the schema already conveys — marginal added meaning over structured data.

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 precise verb+resource behavior: keep the date if it is already a business day, otherwise move it to the nearest business day in the given direction. It explicitly bounds itself against neighbors — 'not Excel WORKDAY' and 'does not decide whether a filing is timely' — which separates it from frcp_6a_deadline and add_business_days.

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?

Gives clear usage context: the no-op case, the two directions, and the default-calendar rule ('Omit calendar for us-federal-opm'). It also flags when this tool is the wrong choice (filing timeliness), though it never names the sibling an agent should use instead, so routing is implied rather than explicit.

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