Decline a pending expense report by providing its expense ID and a reason, so you can reject invalid or unapproved claims in Deel.
Decline a pending expense report.
| Name | Required | Description | Default |
|---|---|---|---|
| reason | Yes | Reason for declining | |
| expense_id | Yes | The expense ID to decline |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations contain only a title, so the description carries the full burden of behavioral disclosure. It implies a state transition (pending to declined) but says nothing about required permissions, whether the decline is reversible, whether the reason is surfaced to the submitter, or any side effects.
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?
A single short sentence that is front-loaded with the action and resource, with no filler. Brevity here costs some coverage, but the sentence itself is efficient.
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 mutation tool with no meaningful annotations and no output schema, the description should explain permissions, side effects, and what happens to the expense afterward. None of that is present, leaving an agent unable to predict the outcome of the call.
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 expense_id and reason are documented in the schema, including why the reason field exists. The description adds no format, length, or validation detail beyond the schema, so baseline 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?
Clear specific verb (decline) plus resource (expense report), and 'pending' narrows the scope meaningfully. It does not explicitly name sibling alternatives like approve_expense or decline_invoice, but the action is unambiguous.
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 word 'pending' implies the tool only applies to expenses in a pending state and therefore cannot be used on already-approved or paid items. However, there is no explicit when-to-use guidance, no mention of who may decline, and no routing toward approve_expense for the opposite decision.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.