arckit-impact

name	arckit-impact
description	Analyse the blast radius of a change to a requirement, decision, or design document

Impact Analysis

You are helping an enterprise architect understand the blast radius of a change to an existing requirement, decision, or design document. This is reverse dependency tracing — the complement of forward traceability.

User Input

$ARGUMENTS

Note: The ArcKit Impact hook has already built a dependency graph from all project artifacts and provided it as structured JSON in the context. Use that data — do NOT scan directories manually.

Instructions

1. Parse the query to identify the change source:

   • ARC document ID (e.g., ARC-001-REQ, ARC-001-ADR-003) → find all documents that reference it
   • Requirement ID (e.g., BR-003, NFR-SEC-001) → find all documents containing that requirement ID
   • Document type + project (e.g., ADR --project=001) → show all dependencies of ADRs in that project
   • Plain text → search node titles and suggest the most likely target

2. Perform reverse traversal using the dependency graph:

   • Level 0: The changed document itself
   • Level 1: Documents that directly reference it (via cross-references or shared requirement IDs)
   • Level 2: Documents that reference Level 1 documents
   • Continue until no more references found (max depth 5)

3. Classify impact severity using the severity field from the graph nodes:

   • HIGH: Compliance/Governance documents (TCOP, SECD, DPIA, SVCASS, RISK, TRAC, CONF) — may need formal re-assessment
   • MEDIUM: Architecture documents (HLDR, DLDR, ADR, DATA, DIAG, PLAT) — may need design updates
   • LOW: Planning/Other documents (PLAN, ROAD, BKLG, SOBC, OPS, PRES) — review recommended

4. Output format (console only — do NOT create a file):

   ## Impact Analysis: BR-003 (Data Residency Requirement)
   
   ### Change Source
   - **Requirement:** BR-003 — "All customer data must reside within UK data centres"
   - **Defined in:** ARC-001-REQ-v2.0 (projects/001-payments/)
   
   ### Impact Chain
   
   | Level | Document | Type | Impact | Action Needed |
   |-------|----------|------|--------|---------------|
   | 1 | ARC-001-ADR-002-v1.0 | ADR | MEDIUM | Review cloud provider decision |
   | 1 | ARC-001-HLDR-v1.0 | HLDR | MEDIUM | Update deployment architecture |
   | 2 | ARC-001-SECD-v1.0 | SECD | HIGH | Re-assess data protection controls |
   | 2 | ARC-001-DPIA-v1.0 | DPIA | HIGH | Re-run DPIA assessment |
   | 3 | ARC-001-OPS-v1.0 | OPS | LOW | Check operational procedures |
   
   ### Summary
   - **Total impacted:** 5 documents
   - **HIGH severity:** 2 (compliance re-assessment needed)
   - **MEDIUM severity:** 2 (design updates needed)
   - **LOW severity:** 1 (review recommended)
   
   ### Recommended Actions
   1. Re-run `$arckit-secure` to update Secure by Design assessment
   2. Re-run `$arckit-dpia` to update Data Protection Impact Assessment
   3. Review ADR-002 decision rationale against updated requirement
   

5. Recommend specific $arckit- commands for HIGH severity impacts:

   • SECD impacted → $arckit-secure
   • DPIA impacted → $arckit-dpia
   • TCOP impacted → $arckit-tcop
   • HLDR impacted → $arckit-hld-review
   • RISK impacted → $arckit-risk
   • TRAC impacted → $arckit-traceability

6. If no impacts found, report that the document has no downstream dependencies. Note this may indicate a traceability gap — suggest running $arckit-traceability to check coverage.

7. If the query matches multiple documents, list them and ask the user to specify which one to analyse.

Suggested Next Steps

After completing this command, consider running:

• $arckit-traceability -- Update traceability matrix after impact assessment (when Impact analysis revealed traceability gaps)
• $arckit-health -- Check health of impacted artifacts (when Impacted documents may be stale)
• $arckit-conformance -- Re-assess conformance after changes (when Impact includes architecture design documents)