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

The readOnlyHint=true annotation is reinforced by 'returns how to do it... opens nothing by itself', which tells the agent this is a knowledge/instructions tool rather than a mutation. The API-and-scopes paragraph explains why browser automation is needed, adding context beyond the annotations, though it says nothing about the format or length of the returned steps.

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 purpose and the follow-up tooling are front-loaded in the first two sentences, which is good structure. However, the third sentence about Fortnox's public REST API, registration, scopes and licensing is long, dated, and does not help an agent decide to call this zero-parameter tool, so it dilutes an otherwise tight definition.

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 zero-parameter, read-only guidance tool with no output schema and full annotation coverage, the description supplies what matters: what it returns and how to act on it. The API-licensing aside is extra context rather than a missing piece.

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 tool takes no parameters, so there is nothing for the description to disambiguate; baseline applies. The description correctly implies no inputs are needed before returning the walkthrough.

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 returns step-by-step instructions for booking a voucher in Fortnox, resolving the ambiguity of the imperative name 'book_voucher'. It distinguishes itself from action tools by stating it 'opens nothing by itself' and points to the cotlet_browser_* tools as the execution path.

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?

It gives clear sequencing guidance: call this to get the steps, then perform them with cotlet_browser_* in the user's Fortnox Cloud Browser. It does not address when to prefer the other Fortnox siblings (e.g. fortnox_create_invoice) or when booking a voucher is the wrong choice, so no exclusions are stated.

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