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

Annotations already declare destructiveHint=true and readOnlyHint=false, so the safety profile is covered. The description adds useful behavioral context beyond annotations: the operation is token-guarded (Id + current SyncToken) and returns the saved record with its new SyncToken, which matters for sequential updates. It does not itself mention the sparse-vs-full update behavior, but that is documented in the schema.

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, front-loaded with the action and resource, then the key requirement and return value. Nothing is wasted and no important precondition is 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?

Given the rich input schema, destructive annotation, and absence of an output schema, the description covers the essential call semantics: it updates an existing employee, needs Id and SyncToken, and returns the saved record with a new SyncToken. It omits schema-level details like sparse updates and employee retirement, but those are provided directly in the entity parameter.

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 the entity parameter already documents Id, SyncToken, sparse updates, full-update behavior, and field restrictions. The description repeats the Id/SyncToken requirement but adds little parameter meaning beyond the schema, so the baseline 3 is appropriate.

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 — 'Update an existing employee in QuickBooks Online' — and distinguishes this mutation from sibling operations like create_employee, get_employee, and search_employees. An agent can identify the intended action without opening the schema.

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 makes clear this is for updating an existing employee and requires an Id plus the current SyncToken from a prior search or write. That gives a usable preconditions workflow, but it does not explicitly rule out alternatives or name a specific sibling to use for fetching the employee first.

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