Write a dunning letter

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

With no annotations, the description carries the burden. It discloses key behaviors: refusal when nothing is overdue, no interest stated, level 3 is Pro, and that every overdue invoice is included with age, total, and bank details. It doesn't mention whether the output is text or PDF, but the tool name and siblings suggest text output.

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 sentences with no waste. The core behavior, level semantics, and refusal condition are all front-loaded. Every sentence earns its place.

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 text-generation tool with 6 parameters and no output schema, the description covers the essential behavior, refusal condition, and level semantics. It doesn't specify the output format (plain text vs. formatted), but the sibling statement_text and the tool name make that reasonably clear. Minor gap: no mention of how currency is handled beyond the schema.

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 100%, so the schema already documents all parameters. The description adds context about level meanings and the 'Pro' designation, but doesn't add much beyond the schema for parameters like as_of, client, currency, greeting, and sign_off.

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 states a specific verb ('Write a payment chaser') and resource (overdue invoices), and clearly distinguishes the three levels. It also differentiates from siblings like statement_text by focusing on dunning letters for overdue invoices.

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 explains when to use it (when invoices are overdue) and when not to ('Refused if nothing is overdue'). It doesn't explicitly name sibling alternatives, but the context is clear enough for an agent to select this tool over statement_text or statements_report.

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