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

Annotations declare readOnlyHint=false with idempotentHint=true and destructiveHint=false; the description is consistent and adds genuinely non-obvious behavior: nothing is transmitted, approval by a person is required, and the response explains the delivery path for the approved change. This is the key risk an agent needs to know. It does not cover side effects on the invoice or any rate/permission constraints, so not a 5.

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 compact sentences: action, endpoint reference, then the crucial approval caveat. Front-loaded and free of filler; every sentence carries distinct information.

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?

An output schema exists, so return values need not be described, and the single trivial parameter is fully documented in the schema. Combined with annotations, the approval caveat closes the main gap. It could note prerequisites on the invoice (e.g. must be an unprinted overdue invoice) but is otherwise sufficient to invoke correctly.

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?

One required parameter with 100% schema description coverage ('identifies the invoice'), so the schema already does the explaining. The description adds no additional meaning about DocumentNumber format or where to obtain it, so the baseline 3 applies.

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?

States a specific action (propose printing an invoice as a reminder) and names the underlying Fortnox endpoint, so the resource and scope are unambiguous. The closing sentence clarifies that this is a proposal rather than an actual print, resolving the ambiguity created by the title 'Print an invoice as reminder'. No sibling is explicitly named as the alternative, but the prefix pattern (propose_* vs execute_*) makes the family obvious.

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 frames the tool as prepare-only: 'Only prepares the change for the person to approve; this tool sends NOTHING to Fortnox.' That tells an agent exactly when this tool is the right choice (when a human-approved reminder print is wanted). It does not name a specific alternative tool or state exclusions, so it stops short of a 5.

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