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

Annotations already declare readOnlyHint=false and destructiveHint=false, so the bar is lower, and the description adds real value by explicitly stating 'WRITES to the company's records as a reimbursement request' and disclosing the POST endpoint. The receipt-file exclusion is a non-obvious workflow constraint that the schema cannot express. It stops short of stating permission requirements or duplicate-handling behavior, which is consistent with the non-idempotent hint but never explained.

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?

Three tight sentences with no filler, the write semantics and receipt exclusion stated up front. The nested parentheticals and trailing endpoint make it slightly dense but nothing is wasted.

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 14-parameter mutation with no output schema, the description covers the critical ambiguities: that it writes, that receipts are out of scope, and how the two amount fields relate. What is missing is whether a response contains the created expense identifier and how conditional fields (car_km/car_cost_km for KM, subkind when policy defines it) should be selected.

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 coverage is 100%, so the baseline is 3; the description earns a step up by disambiguating the confusing amount/amount_total pair and clarifying that amount is EUR while amount_total is in amount_total_currency and equal for EUR. That is meaningful over what the individual field descriptions convey. It says nothing about the many KM-only car_* fields or kind-dependent required fields, which remains a gap.

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 specific verb and resource ('Create an expense reimbursement request for an employee') plus the endpoint, so it is unambiguously distinct from the sibling read tools like jethr_list_expenses. It also front-loads the key scope qualifier that receipt files are not part of this call.

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 one useful usage constraint: receipts are not attached here, they are uploaded in Jet HR, which implies a separate flow. However, it never says when to prefer this over alternatives, what prerequisites to gather first (e.g. employee lookup, expense policy / subkind validity), or whether a matching policy must exist before calling.

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