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

With no annotations, the description carries the transparency burden. It discloses the core behavior (monthly compounding, adding new revenue, subtracting churn, applying expansion, outputting ARR and months to milestone), but it omits details about assumptions, parameter units, edge cases, or how the targetMrr optional parameter affects output. It adds enough context to understand the basic operation but lacks depth.

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 concise, two sentences, with the title repeated but immediately followed by substantive details. Every clause adds value: "monthly compounding," the three inputs, and the output. No fluff or redundancy.

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 six-parameter calculator with no output schema and no annotations, the description lacks critical details such as parameter format, required vs optional inputs, output structure beyond ARR and months, and behavior when targetMrr is omitted. It is too sparse for an agent to reliably invoke the tool in varied scenarios.

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%, and the description does not map its concepts ("new revenue," "churn," "expansion") directly to parameter names or clarify units (percent vs decimal, dollars vs thousands). It provides only high-level domain meaning, insufficient for an agent to correctly populate parameters without additional schema descriptions.

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 uses a specific verb ("Model") and resource (SaaS MRR growth) and clarifies the mechanics: "add new revenue, subtract churn, apply expansion." It explicitly distinguishes this from sibling calculators by focusing on MRR growth projection with monthly compounding, not just churn rate or ARR alone.

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 implies usage for projecting SaaS MRR growth over time, but it does not state when to choose this tool over alternatives like churn_rate_calculator or break_even_calculator. No exclusions or alternative tool references are provided, so the context is clear but not explicit.

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