Cancel Fortnox Invoice

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

Annotations already indicate destructive behavior (destructiveHint=true), so the bar is lower. The description adds meaningful context by explicitly stating that booked invoices will have reversal entries created, which clarifies the side effect and provides insight beyond the 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?

The description is extremely concise, with a clear one-sentence purpose, a compact Args list, and a Returns note. No unnecessary words or redundant information, making it easy to parse and act upon.

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 the simple two-parameter schema, the description covers the return value ('Confirmation of cancellation') and a key side effect (reversal entries). It's adequate for a straightforward cancellation tool, though it does not mention error handling or permissions, which are not critical for basic use.

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%, so both parameters are fully documented in the schema. The description repeats the parameter names and types without adding extra meaning or nuance, which meets the baseline for coverage but does not exceed it.

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 tool's function with a specific verb and resource: 'Cancel an invoice.' It also distinguishes the behavior for booked invoices by mentioning reversal entries, which sets it apart from related tools like credit invoice or delete.

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?

No guidance is provided on when to use this tool versus alternatives such as fortnox_credit_invoice or fortnox_delete_customer. The description simply explains the action without contextual direction, leaving the agent to infer appropriate usage.

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