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Impact analysis example

What breaks when you change Payload CMS (packages/payload)?

Real arc impact output on Payload CMS (packages/payload) — same structure as the homepage demo. Know blast radius before you merge.

Project: Payload CMS (packages/payload) · Score: 71.1/100 (Moderate technical debt) · 627 modules · 2,704 edges

Engineering decision simulation

Validation procedure 01 · merge vs. hold before output

Before arc impact

You plan a change to a high fan-in module in Payload CMS (packages/payload). Would you merge without knowing blast radius?

Typical answer: hold — need dependency context.

After arc impact

Structured output below: score, hotspots, corridors, and high-risk modules — same field schema as the homepage proof.

Decision: confirm hold, narrow change, or inspect paths first.

Published as part of the validation record. Run locally: arc impact <file-you-are-changing>

Architectural Risk Map

Where risk accumulates by control surface — drill down Surface → Substrate → Mechanism → Evidence.

See control surfaces →

Dependency evidence

Architecture visualization

Diagrams are generated from ArcSight analysis data. Dependency graph and risk map show key modules; subsystem view shows high-level structure.

Dependency graph
Dependency graph for this codebase
Subsystem architecture
Subsystem architecture for this codebase
Risk map
Risk map for this codebase

Architecture score & metrics

Score: 71.1/100 · Stability: 0/100 · Status: moderate_risk · Confidence: 100%

  • Dependency cycles: 100+
  • Duplicate authorities: 19

Modules to inspect

One row per module. Fan-in is direct dependents. Blast radius is downstream modules reachable from that file.

Fan-in, direct dependents
  • src/types225 dependents
  • src154 dependents
  • src/config/types142 dependents
  • src/collections/config/types128 dependents
  • src/fields/config/types124 dependents
  • src/errors/APIError41 dependents
  • src/versions/types16 dependents
  • src/utilities/isNumber14 dependents
Blast radius, downstream modules
  • src/errors/APIError495 modules
  • src/versions/types477 modules
  • src/utilities/isNumber477 modules
  • src/types476 modules
  • src476 modules
  • src/config/types476 modules
ModuleFan-inBlastRisk
src/errors/APIError41495CRITICAL
src/versions/types16477CRITICAL
src/utilities/isNumber14477CRITICAL
src/types225476CRITICAL
src154476CRITICAL
src/config/types142476CRITICAL
src/collections/config/types128CRITICAL
src/fields/config/types124CRITICAL

Architectural gravity centers

  • src/errors/APIError— concentrates too many responsibilities
  • src/errors/APIError— shared utility hub
  • src/versions/types— concentrates too many responsibilities
  • src/versions/types— shared utility hub
  • src/utilities/isNumber— concentrates too many responsibilities

CLI workflow

Scan → Fix → Finish → Watch. Nothing else required.

  • arc scanFind issues
  • arc fixApply fixes
  • arc finishResolve remaining
  • arc watchKeep clean

More commands (explain, impact, guard…) →

Key takeaways

  • •Structural scan reports dependency cycles — inspect impact paths before refactors that cross module boundaries.
  • •High fan-in modules are change-risk zones; run arc explain <path> before refactoring.
  • •Run the full workflow (analyze, hotspots, explain, impact, snapshot, drift) in your repo for deterministic architecture insights.

Run ArcSight on your repo

Install the CLI and run analyze, then hotspots and explain for the same workflow.

npm install -g arcsight
arc analyze
Install ArcSight →

This case study is generated from ArcSight analysis data. View short analysis. View all analyses