Restore cancelled invoice

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

Annotations already indicate idempotent and non-destructive; the description adds that it is an undo operation with specific limitations (no effect on non-cancelled, no restore for deleted), which complements annotations well.

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 sentences with no wasted words: first sentence states core action, second gives usage context, third clarifies edge cases. Well-structured and front-loaded.

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 full parameter coverage and annotations, the description covers purpose, usage, and limitations completely. No output schema is needed for a state-changing tool; the behavior is fully described.

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 baseline 3 applies. The description does not add any parameter detail beyond the schema, but the schema itself is sufficiently descriptive.

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 'undo cancel_invoice' and the resource 'cancelled invoice', and distinguishes from siblings like cancel_invoice and delete_invoice by specifying it only works on cancelled invoices, not deleted ones.

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 description explicitly states when to use ('when an invoice was voided by mistake and should count again') and when not to use ('no effect on never-cancelled', 'cannot bring back deleted'). This provides clear context and exclusions.

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