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

Annotations already cover read-only, idempotent, non-destructive and open-world traits, so the description adds genuine context beyond them: USD-only constraint, the shared 'yearly low/high average' pricing model with SmartMoney77, and the per-asset reproduction link returned. Useful behavioral detail, though auth/rate-limit or error behavior is absent.

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 purpose, scope and output in three dense sentences plus a worked example. The inline asset enumeration is somewhat redundant with the schema but is still readable and earns its place as a quick reference.

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?

Given an output schema exists, the description needn't explain return values, yet it still previews the ranked result and reproduction link. Combined with the example and pricing methodology, an agent has everything needed to invoke it correctly.

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 100%, so the baseline is 3, but the description adds value with a concrete example payload showing how amount, buy_year and assets combine and clarifying the ranked output order. The asset slug list duplicates the schema, which slightly blunts the added value.

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 and resource ('run the same what-if-I-had-invested calculation across 2-8 assets and rank them by final value'), which cleanly separates it from the single-asset historical_investment_return and from compound_interest. The asset universe and ranking output are named up front.

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?

Use is implied by 'across 2-8 assets and rank them' (i.e., pick this when comparing multiple assets), but the description never explicitly says when to prefer it over historical_investment_return or compound_interest, nor does it state exclusions. Adequate but with a clear routing gap.

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