fortnox_preview_receipt

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

With no annotations, the description carries the full behavioral burden, and it does disclose the most important trait: this call is non-mutating. However, it says nothing about what happens on validation failure (error vs. partial preview), whether a preview token/state is returned, or any rate/permission constraints.

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?

One tightly packed sentence that leads with the action and ends with the critical non-write guarantee. No filler, no redundancy.

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?

The core contract (validate + preview, no side effects) is conveyed, which matters most with no annotations and no output schema. But for a tool whose only input is an opaque nested object and whose output is a "balanced voucher," the description leaves both the input shape and the preview result undefined.

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?

The single required parameter is a nested object with 0% schema description coverage, so the description should explain the receipt structure (line items, amounts, account codes) needed for a balanced voucher. It offers no parameter detail whatsoever, leaving the agent to guess the shape of the nested payload.

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 names a specific verb pair ("Validate", "build a balanced voucher preview") and the resource (a receipt), and the negative clause "does not write to Fortnox" makes the scope unambiguous. This clearly distinguishes it from the sibling list tools, which are plain read queries.

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 phrase "does not write to Fortnox" implies this is the pre-commit dry-run step before actually booking a voucher, which is useful context, but no alternative tool or explicit trigger condition is named. Usage must be inferred rather than being stated.

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