strategy_compare

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

Annotations already state readOnlyHint=true and destructiveHint=false, and the description adds valuable non-obvious behavior: bars are fetched once for all nine strategies so cost equals a single backtest, and results are ranked above buy-and-hold rather than by raw return. It also warns that picking the winner on one window is a selection, not a finding. No contradiction with annotations.

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 three focused sentences, each earning its place: the action/cost, the ranking rationale, and the selection-bias warning. It is front-loaded with the primary behavior and contains no filler or repetition.

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?

The core contract is well covered: what it runs, what it costs, how it ranks, and what to do next. However, there is no output schema and the description does not specify the result structure beyond 'rank them,' so an agent cannot know exactly what fields to expect. For an 8-parameter tool this is mostly but not fully 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?

The description reinforces the meaning of `strategies` ('all nine' by default) and explains that costs like stop-loss/take-profit are included in the ranking metric. However, it does not clarify `to`/`from` formats, `initial_capital`, or `stop_loss_pct` defaults. With schema coverage at 50%, the missing parameter semantics are only partially compensated.

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 opens with a specific verb and resource: 'Run every built-in strategy over ONE stock's history and rank them.' It clearly differentiates from the sibling `backtest` tool by framing strategy_compare as a comparison/screening tool, and the closing caveat about selection vs. finding reinforces its distinct role.

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?

The description explicitly tells the agent when to take the result seriously: 'Run `backtest` with walk_forward on the winner before believing it.' It also explains that the ranking is by excess return over buy-and-hold, not raw return, which prevents misuse on rising windows. This gives clear selection and follow-up guidance relative to `backtest`.

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