Unpaid Invoices Report

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

Annotations already declare readOnly, openWorld, idempotent, and non-destructive hints. The description adds substantial context beyond that: truncation warnings for >10,000 invoices, error response format, age bucket definitions, and the impact of include_details on output. This far exceeds the baseline expectation.

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 well-structured with clear sections (main description, example questions, Args, Returns, Age Buckets, Examples, Error Handling). It is thorough yet concise, front-loading the core purpose and using bullet-style formatting for readability.

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?

Given no output schema, the description fully explains the return structure for both JSON and Markdown, lists age buckets, and documents error handling. It also provides enough guidance on parameter combinations to cover the tool's complexity.

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 provides 100% coverage of parameter descriptions, so a baseline of 3 applies. The description adds practical examples, default values, and parameter semantics in the Args section, reinforcing but not drastically extending schema information. It earns a 4 because it clarifies usage patterns like min_amount=50000.

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 specifies a clear verb and resource: 'Generate an accounts receivable aging report for unpaid invoices.' It distinguishes this from sibling tools like fortnox_list_invoices (listing) and fortnox_payables_report (payables) by focusing on unpaid invoices and aging buckets.

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 description answers common questions and provides concrete examples (full aging report, large invoices, specific customer). It implies when to use this report versus other financial tools, but does not explicitly name alternatives or exclusionary conditions, so it falls 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.