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

Annotations already declare readOnly, idempotent, non-destructive, and closed-world, so the safety profile is covered. The description adds genuinely new behavioral facts: pure arithmetic with no I/O or external calls, no auth or rate limits, output rounded to 2 decimals, and error-on-unknown-method/missing-parameter behavior. Only slightly below top marks because the return-field listing partly overlaps the existing output schema.

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?

Dense but well-organized: technique enumeration, then routing guidance, then per-method parameter mapping, then output/error behavior. Nearly every sentence carries information, though the return-value sentence is somewhat redundant given the output schema.

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 an 8-parameter, one-required method-dispatch tool with full schema coverage and an output schema, the description covers selection, per-method parameter requirements, unit conventions, and failure modes. Nothing an agent needs to invoke it correctly is missing.

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 baseline is 3. The description goes beyond that by mapping parameters to methods (black_scholes/binomial need underlying+strike+risk_free_rate+volatility+time_to_maturity, binomial adds steps, scenario_analysis needs scenarios) and by confirming fraction/[0,1] conventions and that omitted method-relevant defaults apply.

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 opening states specific techniques (Black-Scholes call value, binomial-tree option value, scenario analysis) and the controlling parameter (method selects the technique). It explicitly distinguishes itself from siblings, naming valuation_probability for quick expected values and valuation_time_value for DCF, so an agent can route without opening any schema.

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?

Explicit when-to-use and when-not-to-use guidance is given: scenario_analysis here is for explicit named bull/base/bear tables, whereas arbitrary outcome lists should go to valuation_probability; plain DCF belongs to valuation_time_value. It also states only method is required and that the remaining parameters are method-dependent.

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