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Haircut Sharpe ratio

validate_haircut_sharpe

Calculate the haircut Sharpe ratio required to account for multiple testing, applying Bonferroni, Holm, and BHY corrections to determine if an observed Sharpe ratio survives the number of tests run.

Instructions

Haircut Sharpe ratio for multiple testing (Harvey and Liu, 2015): the Sharpe a single test would have needed once the number of tests is counted, by Bonferroni and for independent tests, and with the other tests' Sharpe ratios by Holm and BHY. A deflated Sharpe or overfitting probability above or below any threshold is not admission to anything and is not a forecast.

Input Schema

TableJSON Schema
NameRequiredDescriptionDefault
testsNoTotal tests run, this one included; gives the Bonferroni and independent-test haircuts.
observationsYesNumber of return observations behind the Sharpe ratio.
autocorrelationNoFirst-order autocorrelation of the returns, -1 to 1; default 0. Corrects the annualized Sharpe as Lo (2002).
periods_per_yearYesObservations per year: 252 daily, 365 daily crypto, 52 weekly, 12 monthly.
observed_sharpe_annualizedYesAnnualized Sharpe as observed.
other_sharpe_ratios_annualizedNoAnnualized Sharpe ratios of the other tests, over the same observations; adds the Holm and BHY haircuts.

Schema Changelog

Changes observed during successful MCP inspections.

  1. Addedv0.6.0

TDQS

A3.6/5.0
Behavior3/5

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

Annotations already set readOnlyHint=false and destructiveHint=false. The description adds algorithmic transparency by listing the four correction methods and an interpretive caveat, but it does not clarify potential side effects, external dependencies, or why readOnlyHint is false for what appears to be a pure validation calculation.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences with the main purpose front-loaded and no filler. The second sentence is slightly tangential but serves as a useful misuse guardrail. Overall it is compact and readable.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

There is no output schema, and the description never states the return shape: a single number, a set of haircut values, or a structured result per method. For a tool with six parameters and multiple statistical corrections, an agent cannot confidently predict what the tool will return or how to interpret the different haircuts.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters4/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The schema already provides 100% parameter coverage with detailed descriptions. The description adds methodological linkage beyond the schema, such as the 'tests' parameter driving Bonferroni and independent-test haircuts, and 'other_sharpe_ratios_annualized' enabling Holm and BHY adjustments.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly defines what the tool computes: the haircut Sharpe ratio needed for statistical significance after accounting for multiple testing, naming specific methods (Bonferroni, independent tests, Holm, BHY). This distinguishes it from sibling validation tools like validate_deflated_sharpe, though it lacks an explicit action verb like 'calculates' or 'returns'.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines4/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description scopes the tool to multiple-testing contexts and explicitly warns that the output is not a forecast or admission criterion, providing a when-not-to-interpret indication. However, it does not directly name alternative sibling tools for scenarios like deflated Sharpe or overfitting probability.

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