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

With no annotations, the description carries the burden of behavioral disclosure. It accurately describes the calculation outcome, but does not detail assumptions like compounding frequency, whether returns are applied monthly or annually, or whether the withdrawal is adjusted for inflation. These are relevant behavioral traits for a drawdown calculator. The description is adequate 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 a single, tightly written sentence that front-loads the purpose and condenses the inputs and output into a compact phrase. Every word adds value, and there is no redundancy or extraneous detail. This is exemplary conciseness.

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 simple calculator with no output schema, the description adequately covers the necessary information: what the tool does, what inputs are needed, and what the output is. It could be improved by specifying the output format (e.g., a table of months/years) or mentioning calculation assumptions, but overall it is complete for the tool's expected use case.

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%, so the description must compensate for parameter meaning. It uses common terms ('balance', 'monthly withdrawal', 'expected return') that map to the schema properties, but 'expected return' is ambiguous regarding format (percentage vs. decimal) and frequency. The schema property 'annualReturnPct' and its min/max constraints clarify it, but the description alone is not sufficient to disambiguate units.

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 clearly states the tool's purpose: to calculate how long savings will last until depletion, given balance, monthly withdrawal, and expected return. This is a specific verb+resource combination that distinguishes it from sibling financial calculators like required_savings_calculator or savings_goal_calculator, which target different questions.

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 by specifying the required inputs (balance, monthly withdrawal, expected return) and the output (months and years until money runs out). It provides clear context for when to use the tool, though it does not explicitly mention alternatives or exclusions. Since the tool is a simple calculator, this level of guidance is sufficient.

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