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

Annotations already declare readOnly/destructive=false/openWorld=false, so the safety profile is covered. The description adds real context beyond that: output contents, the pricing model (free daily allowance then $0.20 USDC via x402), and that no account or API key is required. The one gap is a truncated sentence ('the t that pure'), which leaves a return value unexplained.

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 core framing is front-loaded and useful, but the description is redundant ('You tested N strategies and kept the best' vs 'Use when you searched many strategies...') and the sentence 'the t that pure' is cut off mid-thought, and pricing/logistics clutter the entry.

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?

For a simple two-parameter tool with no output schema, the description does explain the key returns (family-wise p-value, needed t). It is nearly complete, losing a point only for the truncated return-value sentence and sparse handling of the example payload's meaning.

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 descriptions only contain bare examples ('example: 3.0'), so they carry little semantics despite nominal 100% coverage. The description supplies the actual meaning: 'the number of things you tested' (n_tested) and 'the winner's t-statistic' (best_t), adding value the schema does not.

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 states a specific statistical operation: correcting a winning backtest for multiple testing, returning the family-wise p-value and the t-stats needed. It's clearly a multiple-testing tool, distinguishable from siblings like samplesize and deflatedsharpe. It doesn't explicitly name a sibling it's not, so not a 5.

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 gives an explicit trigger: 'Use when you searched many strategies or parameter sets and kept the best one,' plus the motivating failure mode (quoting a winner's solo p-value). Clear adoption context, but no explicit when-not or named-alternative routing.

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