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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world behavior, but the description adds valuable behavioral context: pure arithmetic with no I/O or external calls, numeric results rounded to 2 decimals, unknown methods or missing required parameters return an error, and parameters belonging to other methods are accepted and ignored.

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 dense but appropriately sized for a tool with 23 parameters and 7 distinct formulas. It is front-loaded with purpose and method-selection guidance, then systematically lists per-method parameter needs, and every sentence contributes necessary information without repetition or fluff.

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 complex multi-method calculation tool with full schema coverage, annotations, and an output schema, the description is complete. It covers method selection, per-method prerequisites, default behavior, error handling, numeric rounding, and the fact that irrelevant parameters are ignored, leaving no gaps an agent would need to fill.

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 the schema already documents each parameter individually, but the description adds crucial method-dependent semantics: it maps each of the seven methods to its required and optional parameters, notes that wacc requires both equity_value and debt_value, specifies that dlom_finnerty volatility is annualized, and clarifies that only method is required while other parameters are method-specific.

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 (Construct) and resources (discount and capitalization rates), lists all seven supported methods, and explicitly distinguishes itself from the sibling valuation_time_value for discounted cash flows. An agent can identify exactly what the tool does and how it relates to the income-based methods.

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?

Gives explicit when-to-use guidance: method selects the formula, use for the rate that feeds income-based methods, use currency_adjusted for cross-border rates, and use valuation_time_value for the cash flows themselves. It names the alternative tool and the condition that selects it, leaving nothing to inference.

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