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

Annotations are sparse, so the description usefully adds that this affects only display, does not alter tax logic, that empty strings remove header lines, and that the updated settings are returned. It does not cover permissions or side effects beyond display changes, but the key behavioral boundaries are clear.

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 dense but front-loaded with the core purpose and then organized parameter by parameter. It is appropriately sized for four undocumented parameters, though the long iva_display parenthetical could be slightly easier to scan.

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 mutation tool with no output schema and 0% schema description coverage, the description is nearly complete: it explains scope, parameter effects, and return behavior. It could be stronger by explicitly naming when to prefer sibling tools.

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 0%, so the description carries the full burden and does so well. It explains every parameter: all iva_display enum meanings, the badge default and hiding behavior, and that empty header values remove the printed line.

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 specific verb and resource: changing how invoice PDFs are printed/displayed. It distinguishes display-only behavior from tax logic, though it does not explicitly differentiate from nearby siblings such as get_invoice_display or set_invoice_defaults.

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 useful context: display only, no tax logic, and 'Pass only what changes'. However, it does not explicitly state when to use this instead of get_invoice_display, set_invoice_defaults, or set_invoice_footer.

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