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identify_cross

Detect residual cross-correlations between time series pairs to reveal dynamic links and return candidate cross orders and contemporaneous covariance terms for VARMA identification.

Instructions

N2 — What the univariate models do NOT carry: residual cross-correlations.

Reads the CCFs of the residuals of the diagonal system, pair by pair. Those residuals are each series' own innovations — prewhitened by construction — so a cross-correlation beyond the band is evidence of a dynamic between the series. Contemporaneous correlation points to a full innovation covariance; lead-lag correlation points to cross orders p (and q). Returns the evidence and the menu of candidates, each with its argument. It does not choose.

nlags defaults to twice the frequency (24 for monthly data).

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "name": "<name>"
    },
    "name": "identify_cross"
  }
}

Input Schema

NameRequiredDescriptionDefault
nameYes
nlagsNo

Output Schema

NameRequiredDescriptionDefault
resultYes

Schema Changelog

Changes observed during successful MCP inspections.

  1. First observedv0.2.0

TDQS

B3.4/5.0
Behavior4/5

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

With no annotations, the description carries the full burden and does well: it explains prewhitening, how contemporaneous vs lead-lag correlations should be interpreted, that the tool returns evidence and a candidate menu, and explicitly that 'It does not choose.' It stops short of stating read-only/no-side-effect status or computational cost.

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?

Four dense sentences, front-loaded with the core purpose, and each sentence adds interpretation or return semantics. The cryptic 'N2' label and unexplained jargon like 'band' introduce minor friction but little waste.

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

Completeness3/5

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

An output schema exists, so the return shape need not be explained, and the conceptual interpretation guidance is valuable. However, the undefined required `name` parameter and the nlags default mismatch leave an agent without enough information to invoke the tool confidently.

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

Parameters2/5

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

Schema description coverage is 0%. The description only addresses `nlags` (twice frequency, 24 for monthly data) and leaves the required `name` parameter entirely undefined. Worse, the schema default for `nlags` is 0 while the description says it defaults to twice the frequency, creating invocation ambiguity.

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?

States a specific operation: reading residual CCFs pair by pair and returning cross-correlation evidence plus candidate structures. It distinguishes itself from univariate models, but does not explicitly differentiate from sibling identification tools such as identify_matrices or identify_echelon.

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

Usage Guidelines3/5

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

The 'N2' label and contrast with univariate models imply this is a post-univariate identification step, but there is no explicit 'use this when' or 'do not use this when' guidance. It also names no alternatives among the several identification siblings.

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