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

No annotations are provided, so the description carries the full behavioral burden, and it does disclose the $0.10 cost and the benchmark used. However, it says nothing about whether the operation is read-only, whether it has rate or data-availability limits, or what the simulation returns, leaving meaningful gaps for a compute-style tool.

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?

Two terse sentences with the core action front-loaded and the price parked at the end; nothing is wasted. The cost fragment and the vague 'multiple years' keep it just below a 5.

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 annotations and no output schema, the description does not explain what a backtest returns (equity curve, metrics, period, units) or any data-window constraints. The parameters are covered by the schema, but the result-shape gap leaves the definition only minimally complete.

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 schema already documents tickers, weights (summing to 1.0), and initialCapital. The description adds no parameter meaning beyond that, which matches the baseline 3 when the schema does the heavy lifting.

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 (backtest) and resource (a stock strategy over multiple years) plus the benchmark it runs against, which is more than a restatement of the name. It does not name or differentiate itself from siblings like evaluate_tsunami_strategy or analyze_stock_ai, so an agent still has to infer which strategy tool applies.

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?

There is no when-to-use, when-not-to-use, or alternative-tool guidance. With siblings such as evaluate_tsunami_strategy and analyze_stock_ai available, the description leaves the agent to guess which one fits a given request.

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