diff --git a/README.md b/README.md
index b79af56..744df29 100644
--- a/README.md
+++ b/README.md
@@ -274,6 +274,7 @@ Run a read-only health snapshot from the Debian server with:
 ./jeannie capacity
 ./jeannie recover-plan
 ./jeannie recover-power --dry-run
+./jeannie impact --since HEAD~1
 ./jeannie scorecard
 ./jeannie explain scorecard
 ./jeannie gitops-status
@@ -330,6 +331,10 @@ edge verification.
 Debian runtime, Gitea, RPi DNS, Pimox workers, Kubernetes, GitOps/apps, and
 edge/public checks. Use `recover-power --dry-run` to preview the sequence.
 
+`impact` explains what a change may touch before you apply it. Use
+`./jeannie impact --since HEAD~1` for the last commit or pass paths
+like `bootstrap/edge` and `apps/website`.
+
 `scorecard` rolls up backup readiness, GitOps health, DNS/RPi health, cluster
 health, edge health, capacity pressure, security posture, public certificates,
 inventory, and docs freshness into a compact pass/warn/fail report.
diff --git a/README.md.tmpl b/README.md.tmpl
index 634627a..26f4cd0 100644
--- a/README.md.tmpl
+++ b/README.md.tmpl
@@ -274,6 +274,7 @@ Run a read-only health snapshot from the Debian server with:
 ./{{ main_script }} capacity
 ./{{ main_script }} recover-plan
 ./{{ main_script }} recover-power --dry-run
+./{{ main_script }} impact --since HEAD~1
 ./{{ main_script }} scorecard
 ./{{ main_script }} explain scorecard
 ./{{ main_script }} gitops-status
@@ -330,6 +331,10 @@ edge verification.
 Debian runtime, Gitea, RPi DNS, Pimox workers, Kubernetes, GitOps/apps, and
 edge/public checks. Use `recover-power --dry-run` to preview the sequence.
 
+`impact` explains what a change may touch before you apply it. Use
+`./{{ main_script }} impact --since HEAD~1` for the last commit or pass paths
+like `bootstrap/edge` and `apps/website`.
+
 `scorecard` rolls up backup readiness, GitOps health, DNS/RPi health, cluster
 health, edge health, capacity pressure, security posture, public certificates,
 inventory, and docs freshness into a compact pass/warn/fail report.
diff --git a/docs/jeannie.1.md b/docs/jeannie.1.md
index 5be2163..ff3ad55 100644
--- a/docs/jeannie.1.md
+++ b/docs/jeannie.1.md
@@ -104,6 +104,10 @@ and DuckDNS-to-OCI edge IP drift from the canonical inventory.
 state, workload images, public URL status, and latest Gitea/OpenTofu backup
 pointers.
 
+`impact [--since REF] [PATH...]`
+: Explain which homelab areas are affected by changed files or explicit paths,
+including risk, touched services, validation commands, and apply path.
+
 `backup-status`
 : Report freshness for Gitea backups, OpenTofu state backups, restore drill
 reports, and repo-managed Pi-hole restore inputs. The main `status` cascade
diff --git a/infra/jeannie-impact/rules.tsv b/infra/jeannie-impact/rules.tsv
new file mode 100644
index 0000000..deded13
--- /dev/null
+++ b/infra/jeannie-impact/rules.tsv
@@ -0,0 +1,17 @@
+pattern	area	risk	touches	validate	apply
+bootstrap/edge/	Edge/high public routing	high	OCI edge nginx;public website route;Gitea public route;Tailscale backend path	./jeannie doctor-edge;./jeannie cert-check;curl -I https://lab2025.duckdns.org/	./jeannie plan edge
+bootstrap/cluster/	Kubernetes cluster	high	kubeadm control plane;worker joins;CNI;cluster state	./jeannie doctor-cluster;./jeannie status	./jeannie plan cluster
+bootstrap/platform/	Platform services	medium	Argo CD;monitoring;registry;Traefik dependencies	./jeannie status;./jeannie gitops-status;./jeannie grafana-dashboards list	./jeannie plan platform
+bootstrap/provisioning/	Pimox provisioning	high	Pimox template;worker VMs;preseed/PXE	./jeannie preflight;./jeannie doctor-cluster	./jeannie plan provisioning
+apps/	Applications	medium	GitOps apps;website;security lab;dashboards	./jeannie gitops-status;./jeannie status	./jeannie apps
+apps/website/	Public website	medium	website deployment;public route;image build;Redis/Ollama dependencies	./jeannie status;./jeannie cert-check	./jeannie apps
+infra/rpi-services/	RPi DNS services	medium	Pi-hole;Unbound;Uptime Kuma;RPi Docker	./jeannie doctor-rpi;./jeannie status	./jeannie rpi-services
+infra/gitea/	Gitea	medium	Gitea Docker stack;repo bootstrap;public /git route	./jeannie doctor-gitea;./jeannie doctor-edge	./jeannie deploy-gitea
+infra/arr-stack/	ARR stack	medium	Debian Docker ARR services;volumes under /data/arr	./jeannie status	manual docker compose in infra/arr-stack
+infra/tailscale/	Tailscale policy	medium	Tailnet ACLs;routes;peer access	./jeannie tailnet-policy-check;./jeannie doctor-edge	manual tailnet policy apply
+infra/resource-budgets.yml	Capacity policy	low	resource budget reports;capacity warnings	./jeannie resource-budget;./jeannie capacity	none
+homelab.yml	Canonical inventory	high	all rendered docs;scripts;edge/Gitea/RPi/Pimox IPs	./jeannie inventory-check;./jeannie validate;./jeannie preflight	none
+jeannie	Main operator script	high	all Jeannie commands and pipeline flow	bash -n jeannie;shellcheck jeannie;./jeannie help	none
+scripts/	Jeannie helper scripts	medium	reporting;doctors;automation helpers	bash -n scripts/*;shellcheck scripts/*	none
+README.md.tmpl	Generated docs	low	README.md;operator documentation	scripts/render-docs --check	scripts/render-docs
+docs/	Documentation	low	runbooks;manual pages	scripts/render-docs --check	none
diff --git a/jeannie b/jeannie
index 0adea3a..9a9024d 100755
--- a/jeannie
+++ b/jeannie
@@ -5871,6 +5871,10 @@ ask_homelab() {
     "${REPO_ROOT}/scripts/ask" "${@:2}"
 }
 
+impact() {
+    "${REPO_ROOT}/scripts/impact" "${@:2}"
+}
+
 security_scan() {
     require_debian_server "security-scan"
     "${REPO_ROOT}/scripts/security-scan" all
@@ -6125,6 +6129,7 @@ Operator View And Reports
   capacity                                   Compact capacity and placement report.
   recover-plan                               Print disaster recovery order and prerequisites.
   recover-power [--dry-run]                  Run or preview post-outage recovery.
+  impact [--since REF] [PATH...]             Explain affected lab areas before changes.
   map [--dot]                                Print the homelab dependency map.
   change-journal {list|path}                 Show risky-command journal entries.
   release-snapshot                           Write a pre-change release snapshot.
@@ -6389,6 +6394,9 @@ case "${1:-}" in
     ask)
         ask_homelab "$@"
         ;;
+    impact)
+        impact "$@"
+        ;;
     security-scan)
         security_scan
         ;;
diff --git a/scripts/impact b/scripts/impact
new file mode 100755
index 0000000..cda23e4
--- /dev/null
+++ b/scripts/impact
@@ -0,0 +1,104 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+REPO_ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+RULES_FILE="${HOMELAB_IMPACT_RULES:-${REPO_ROOT}/infra/jeannie-impact/rules.tsv}"
+
+usage() {
+    cat <<'EOF'
+Usage: ./jeannie impact [--since REF] [PATH...]
+
+Explain which homelab areas are touched by changed files or explicit paths.
+Default mode analyzes the current working tree diff.
+EOF
+}
+
+since=""
+paths=()
+while [ "$#" -gt 0 ]; do
+    case "$1" in
+        --since)
+            since="${2:-}"
+            shift 2
+            ;;
+        -h|--help|help)
+            usage
+            exit 0
+            ;;
+        *)
+            paths+=("$1")
+            shift
+            ;;
+    esac
+done
+
+if [ ! -s "$RULES_FILE" ]; then
+    echo "Missing impact rules: $RULES_FILE" >&2
+    exit 1
+fi
+
+if [ "${#paths[@]}" -eq 0 ]; then
+    if [ -n "$since" ]; then
+        mapfile -t paths < <(git -C "$REPO_ROOT" diff --name-only "$since"...HEAD)
+    else
+        mapfile -t paths < <(git -C "$REPO_ROOT" status --short | awk '{print $NF}')
+    fi
+fi
+
+if [ "${#paths[@]}" -eq 0 ]; then
+    echo "No changed files or paths to analyze."
+    exit 0
+fi
+
+python3 - "$RULES_FILE" "${paths[@]}" <<'PY'
+import csv
+import sys
+
+rules_file = sys.argv[1]
+paths = [path.strip() for path in sys.argv[2:] if path.strip()]
+
+with open(rules_file, encoding="utf-8", newline="") as handle:
+    rules = list(csv.DictReader(handle, delimiter="\t"))
+
+matches = []
+for path in paths:
+    normalized = path.removeprefix("./")
+    for rule in rules:
+        pattern = rule["pattern"]
+        if normalized == pattern.rstrip("/") or normalized.startswith(pattern):
+            matches.append((normalized, rule))
+
+print("Jeannie Impact")
+print("==============")
+print("Files:")
+for path in paths:
+    print(f"  {path}")
+
+if not matches:
+    print("\nNo specific impact rule matched.")
+    print("Validate:")
+    print("  ./jeannie validate")
+    raise SystemExit(0)
+
+seen = set()
+print("\nImpacted Areas")
+for path, rule in matches:
+    key = (rule["area"], rule["risk"])
+    if key in seen:
+        continue
+    seen.add(key)
+    print(f"\n- {rule['area']}")
+    print(f"  risk: {rule['risk']}")
+    print("  touches:")
+    for item in rule["touches"].split(";"):
+        print(f"    - {item}")
+    print("  validate:")
+    for command in rule["validate"].split(";"):
+        print(f"    {command}")
+    if rule["apply"] != "none":
+        print("  apply path:")
+        for command in rule["apply"].split(";"):
+            print(f"    {command}")
+    else:
+        print("  apply path: none")
+PY