hr_headcount

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

Annotations already establish readOnlyHint=true and destructiveHint=false, so the description is not required to restate safety. It adds useful behavioral context beyond annotations: the report covers active employees, flags pending starts and recent departures, and uses an as-of snapshot date. This gives the agent a clear picture of what the tool does without contradicting the annotations.

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 compact and front-loaded: one informative sentence states the tool's purpose and output, followed by a minimal Args block. Every line adds meaning that is absent from the schema, with no filler or repetition.

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 read-only reporting tool with an output schema, this description is complete. It covers the report scope, the grouping dimensions, the snapshot-date behavior, and all optional parameters. Because an output schema exists, the absence of explicit return-format details is not a gap.

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 0%, so the description carries the full burden of parameter meaning. It fully compensates by documenting all three parameters: message as free-text objective, as_of_date with format and default, and group_by with its allowed values ('team, role, location, manager'). The group_by enumeration is especially valuable because the schema only defines it as a plain string with default 'team'.

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 begins with a specific verb and resource: 'Produce a current-headcount report.' It further specifies the report content ('active employees by team, role, and location') and unique behaviors ('flags pending starts and recent departures'), clearly distinguishing it from the many HR and reporting sibling tools.

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 description clearly implies use for current-headcount reporting and snapshot queries, but it does not explicitly state when not to use it or name alternative tools. The context is unambiguous enough for an agent to choose it over action-oriented or leave-related HR tools, but it lacks explicit exclusions.

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