Create Excel invoice

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

Annotations already declare readOnlyHint=false and destructiveHint=false, and the description goes beyond them by disclosing the non-overwrite guarantee ('Existing files are never overwritten') and the return payload ('absolute path and total'). That is real behavioral context an agent cannot get from the structured fields alone.

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?

Two short sentences, front-loaded with the primary action and destination, followed by the return value and the overwrite constraint. No filler.

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?

Complete for this tool: the write behavior, output location, overwrite policy and return values are all covered, and while the nested-parameter details are thin in the description, the schema itself documents the constrained fields (taxRate, unitPrice, outputFilename, issuer registrationNumber).

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 only 33%, and the description contributes nothing about the nine parameters — issuer/customer shape, currency enum, per-item taxRate and unitPrice conventions, or the optional outputFilename semantics. With a low-coverage schema, the description was expected to compensate and does not.

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 verb and resource ('Save a formatted .xlsx invoice') plus the destination ('configured output directory'), which clearly separates it from a pure calculation tool. It stops short of naming the sibling calculate_invoice, so an agent must infer the create-vs-calculate split.

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?

Usage is implied by 'Save ... in the configured output directory' — you call it when you want a persisted file — but there is no explicit when/when-not guidance and the sibling calculate_invoice is never referenced, leaving the routing decision to inference.

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