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

Annotations already declare readOnlyHint=true and openWorldHint=true, indicating this is a safe read operation. The description adds that it computes forward returns, win rate, and Sharpe, but does not disclose any additional behavioral traits beyond what annotations provide. It does not contradict 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 two functional sentences plus a marketing sentence ('Killer feature...'). The first sentence is dense and effective, but the second sentence is somewhat redundant ('Lets an agent reason about EV before trading'), and the third is promotional and not strictly necessary. It could be trimmed without losing clarity.

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 tool has 6 parameters (2 required) with full schema coverage, and the description explicitly mentions the output (forward returns, win rate, Sharpe) despite lacking an output schema. Annotations cover safety. The description is mostly complete for an agent to understand what the tool does and what it returns.

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 input schema has 100% description coverage for all 6 parameters, and the description does not add new semantic meaning beyond what the schema already provides. The schema already explains parameters like z_score and min_abs_rate with defaults and constraints. Thus, the description adds marginal 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?

The description clearly states: 'Find historical instances of a signal type on an asset over the last N days and compute forward returns (1h/4h/24h), win rate, and Sharpe.' This provides a specific verb ('Find historical instances and compute') and resource ('signal type on an asset'), distinguishing it from sibling tools like get_signal_history or get_signal_performance which do not compute forward returns or Sharpe.

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 says 'Lets an agent reason about EV before trading,' implying this tool should be used when evaluating the expected value of a signal before executing a trade. However, it does not explicitly state when not to use it or mention alternatives, though the sibling tools provide context for other signal-related operations.

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