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

Annotations already declare readOnlyHint=false, destructiveHint=true, and idempotentHint=true, so the safety profile is covered structurally. The description adds nothing beyond that: it does not say the rejection is terminal, whether it can be undone, who is notified, or what the reason field should contain.

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 four-word sentence is short but not concise in any useful sense; it is under-specified rather than economical. Nothing is front-loaded because nothing is present.

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?

This is a destructive, non-read-only mutation with three undocumented parameters, no output schema, and no annotation-independent context in the description. An agent cannot call it correctly on the description alone.

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% across three parameters, and the description supplies no meaning for invoice_id, reason, or note. The distinction between required reason and optional note is left entirely unexplained.

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?

"Reject an invoice" restates the tool name and title almost verbatim, adding no scope, no distinguishing detail. It does not separate this from close siblings like approve_invoice, dispute_invoice, or hold_invoice, so the agent gets no basis for choosing among them.

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 whatsoever on when to reject versus dispute, hold, or escalate an invoice, nor any prerequisite or precondition. The agent must infer usage entirely from the tool name.

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