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

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so safety is covered; the description adds genuinely new context: the geographic scope limit, the exclusion of agency-level closures, the content of the response (status, applicable date, OPM employee guidance), and a cost of 1 credit. That is useful operational detail beyond the structured fields, though it says nothing about caching or how often the status refreshes.

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 question is front-loaded and the scope caveat follows logically, with the cost line clearly separated at the end. The parenthetical list of status values is long but earns its place by telling the agent what to expect. Minor redundancy between 'US Office of Personnel Management's current operating status' and the 'OPM's guidance' phrasing.

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-parameter, no-output-schema lookup, the description covers what is returned, the geographic limitation, and the exclusions, which is most of what an agent needs to decide and call correctly. It could be complete at a 5 with an explicit pointer to the historical sibling or a note on how current the status is.

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 no parameter meaning for the description to establish; the baseline applies. The description correctly implies a no-argument call ('Are federal offices open today?') and adds no misleading input expectations.

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?

It opens with a concrete question the tool answers ('Are federal offices open today?') and names the exact source and resource (OPM's current operating status for the federal government in DC). The enumerated possible return values (open, delayed arrival, early departure, closed, unscheduled leave/telework, lapse in appropriations) make the tool's output unmistakable against any sibling.

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 states concrete use contexts (snow days, funding deadlines) and gives an explicit when-not: DC only, agencies elsewhere set local status, and it does not cover individual agency closures. It stops short of naming the obvious siblings (opm_status_history for past statuses, us_shutdown_now for shutdown specifics), so the alternative 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.