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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered; the description adds real behavioral value by disclosing the exact computation chain, the acceptance-factor cap ('capped at its maximum acceptance factor'), and how run time is derived. It does not describe edge cases such as what happens at zero drawdown or invalid cut-in/cut-out combos.

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?

Front-loaded with the user question and the three deliverables, followed by compact formula lines with zero filler. The formula block is dense but each line maps directly to a computation or output.

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?

With no output schema, the description carries the burden of telling the agent what comes back, and it names drawdown, minimum total tank volume, and the smallest Amtrol model. It stops short of describing return structure (field names, units of the returned model spec), though the formula section covers the logic.

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 coverage is 100%, so baseline is 3; the description goes further by explaining how parameters relate (drawdown = pump gpm × run minutes; acceptance factor from cut-out and cut-in), which clarifies why cut-in/cut-out are needed together. It still doesn't explain the meaning or effect of the optional tank_gal beyond what the schema says.

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+resource: sizing a well pressure tank, computing drawdown, minimum total volume, and the smallest Amtrol Well-X-Trol model. It lists the exact outputs and is clearly distinguishable from the many other calc_* siblings by domain and by the formula given.

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 opening phrase 'What size well pressure tank you need' sets clear usage context, and the formulas imply the input conditions (pump flow, run time, pressure switch setting). However, no alternative tool is named and no exclusions or prerequisites (e.g., when tank_gal should be supplied) are stated.

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