Impact analysis example
What breaks when you change Cal.com (apps/web)?
Real arc impact output on Cal.com (apps/web) — same structure as the homepage demo. Know blast radius before you merge.
Project: Cal.com (apps/web) · Score: 97/100 (Excellent architecture) · 398 modules · 72 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 Cal.com (apps/web). 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.
Architecture score & metrics
Score: 97/100 · Stability: 76/100 · Status: healthy · Confidence: 100%
- Duplicate authorities: 23
Modules to inspect
One row per module. Fan-in is direct dependents. Blast radius is downstream modules reachable from that file.
- components/booking/hooks/useBookingConfirmation3 dependents
- components/booking/types3 dependents
- components/booking/actions/bookingActions2 dependents
- components/booking/actions/BookingActionsStoreProvider2 dependents
- components/security/TwoFactorAuthAPI2 dependents
- components/security/TwoFactorModalHeader2 dependents
- app/_trpc/trpc-client1 dependents
- app/(use-page-wrapper)/settings/(settings-layout)/layout1 dependents
- components/booking/actions/bookingActions2 modules
- components/booking/actions/BookingActionsStoreProvider2 modules
- app/_trpc/trpc-client1 modules
- app/(use-page-wrapper)/settings/(settings-layout)/layout1 modules
- app/providers1 modules
- components/apps/AppPage1 modules
- components/booking/AcceptBookingButton1 modules
- components/booking/actions/BookingActionsDropdown1 modules
| Module | Fan-in | Blast | Risk |
|---|---|---|---|
| components/booking/actions/bookingActions | 2 | 2 | HIGH |
| components/booking/actions/BookingActionsStoreProvider | 2 | 2 | HIGH |
| app/_trpc/trpc-client | 1 | 1 | HIGH |
| app/(use-page-wrapper)/settings/(settings-layout)/layout | 1 | 1 | HIGH |
| app/providers | 1 | 1 | HIGH |
| components/apps/AppPage | 1 | 1 | HIGH |
| components/booking/AcceptBookingButton | 1 | 1 | HIGH |
| components/booking/actions/BookingActionsDropdown | 1 | 1 | HIGH |
| components/booking/RejectBookingButton | 1 | 1 | HIGH |
| components/phone-input/PhoneInput | 1 | 1 | HIGH |
| components/security/DisableTwoFactorModal | 1 | 1 | HIGH |
| components/security/EnableTwoFactorModal | 1 | 1 | HIGH |
| components/booking/hooks/useBookingConfirmation | 3 | LOW | |
| components/booking/types | 3 | LOW | |
| components/security/TwoFactorAuthAPI | 2 | LOW | |
| components/security/TwoFactorModalHeader | 2 | LOW | |
| components/booking/actions/store | 1 | LOW |
CLI workflow
Scan → Fix → Finish → Watch. Nothing else required.
arc scanFind issuesarc fixApply fixesarc finishResolve remainingarc watchKeep clean
Key takeaways
- •Architecture score 97/100 indicates a healthy structure with room to reduce cycles and violations.
- •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.
This case study is generated from ArcSight analysis data. View short analysis. View all analyses