Failures rarely exist in isolation.

If Service A depends on B, and B depends on C, a single degradation can propagate.

Represent dependencies explicitly:

const graph = {
  api: ["auth", "billing"],
  billing: ["database"],
  auth: ["database"]
}

const graph = {
  api: ["auth", "billing"],
  billing: ["database"],
  auth: ["database"]
}

const graph = {
  api: ["auth", "billing"],
  billing: ["database"],
  auth: ["database"]
}

Evaluating Health Across the Graph

If database degrades:

function propagateHealth(node) {
  graph[node].forEach(child => {
    markDegraded(child)
  })
}

function propagateHealth(node) {
  graph[node].forEach(child => {
    markDegraded(child)
  })
}

function propagateHealth(node) {
  graph[node].forEach(child => {
    markDegraded(child)
  })
}

This prevents false assumptions that upstream services are healthy.

Contextual Policy Evaluation

Policies must account for dependency state:

if state.error_rate > 5 and state.dependency_health["database"] == "healthy":
    trigger_incident()

if state.error_rate > 5 and state.dependency_health["database"] == "healthy":
    trigger_incident()

if state.error_rate > 5 and state.dependency_health["database"] == "healthy":
    trigger_incident()

Dependency awareness reduces cascading automation errors.