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

Annotations already indicate destructive hint, but the description adds critical behavioral condition (only draft invoices) and explicitly names an alternative (void_invoice). No contradiction with annotations.

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 waste. Every sentence provides essential information: what it does, conditions, and alternative. Front-loaded with key action.

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 tool with 1 parameter and output schema available, the description covers all necessary context: condition, limitation, and alternative. No gaps.

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?

Only one parameter (invoiceId) with schema coverage 100% and description 'Invoice ID to delete'. The description does not add extra meaning beyond the schema, so 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 clearly states the verb 'delete' and resource 'invoice', specifying it only applies to DRAFT invoices. It distinguishes from the sibling 'void_invoice' by noting the condition 'only invoices that have never been sent can be deleted; otherwise use void_invoice'.

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?

Explicitly states when to use (DRAFT, never sent) and when not to use (otherwise use void_invoice). Provides clear context for tool selection among siblings.

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