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

Without annotations, the description carries the full burden and it does well: it discloses no-lookahead (next bar's close), long-only constraint, return types (trades + metrics), and paid cost. It still leaves out details like minimum data history or error handling, but the provided context is substantial.

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 dense sentence that front-loads the main action, then packs strategy details, no-lookahead behavior, output summary, and pricing into efficient clauses. No waste or redundancy.

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 output schema and no annotations, the description covers behavior, outputs, and cost, but lacks details on performance metric names, behavior with insufficient data, and the purpose of 'params'. It is comprehensive for a moderately complex tool but not fully exhaustive.

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 0%, so the description must compensate. It explains the strategy enum values (SMA 50/200, RSI thresholds, MACD vs signal) and ticker is obvious, but the 'params' object (additionalProperties) is left unexplained, and 'range' is only self-explanatory via its enum values. Partial compensation with a notable gap.

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 it backtests a simple long-only technical strategy on daily price history, names specific strategies, and indicates outputs. This distinguishes it from portfolio-level backtesting tools like run_portfolio_backtest.

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?

It provides clear context: long-only, daily price history, and strategy options. It doesn't explicitly mention when not to use it (e.g., for portfolio-level backtests) or name alternatives, but the scope is logically implied.

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