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

Annotations already declare readOnlyHint=false, destructiveHint=false and openWorldHint=false, so the agent knows this is a contained write operation. The description adds one genuinely useful behavioral fact — that the call returns the saved record with its SyncToken — which matters because no output schema exists. It says nothing about permissions, validation failures, or duplicate handling.

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, zero filler, verb+resource front-loaded and the return-value note placed second. Nothing could be cut without losing information.

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 create tool whose entity shape is well specified in the schema and whose safety profile is covered by annotations, this is adequate but thin. It omits what happens on failure (duplicate names, invalid fields) and does not explain the optional company-selection parameter, which is the only piece of non-obvious behavior an agent might need.

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%: both parameters, including the nested 'entity' object with its data-privacy warning about SSNs, tax IDs, birth dates and card details, are fully documented in the schema. The description adds nothing beyond that, so the baseline of 3 applies.

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 states a specific verb and resource ("Create a department") and scopes it to QuickBooks Online, so an agent can distinguish it from the many other create_* siblings by resource alone. It stops short of explicitly contrasting with neighbors like create_class or search_departments, but the resource name leaves no real ambiguity.

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?

There is no guidance on when to use this tool versus alternatives such as update_department or search_departments, and no prerequisites (e.g., needing an existing company connection) are mentioned. The optional 'company' parameter hints at a multi-company scenario, but the description never explains it.

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