diff --git a/.github/workflows/README.md b/.github/workflows/README.md
index aa92750b..e66b687f 100644
--- a/.github/workflows/README.md
+++ b/.github/workflows/README.md
@@ -285,6 +285,88 @@ The workflow will fail if:
 - Only one deployment runs at a time (group: "pages")
 - New deployments cancel in-progress ones
 
+### 4. `security-scan.yml` - Skill Security Scan
+
+**Purpose**: Scans skills for security vulnerabilities using [cisco-ai-skill-scanner](https://github.com/cisco-ai-defense/skill-scanner) with LLM-powered analysis. Detects prompt injection, data exfiltration, social engineering, and other AI agent security risks.
+
+**Triggers**:
+- **Pull requests** → Scans changed packs only (when `**/skills/**` or `**/mcps.json` change)
+- **Manual dispatch** → Scan specific PR or all packs
+- **Excludes**: Draft pull requests
+
+**Cost optimization**:
+- **Path filters**: Only triggers when skill files or MCP configs change
+- **Concurrency**: Cancels in-progress scans when new commits are pushed
+- **Prerequisite gate**: Waits for `compliance-check` and `skill-linter` to pass before running — if either fails, the scan is skipped to save LLM tokens
+
+**What it checks**:
+- YAML/manifest injection risks
+- Command injection via untrusted inputs
+- Supply chain risks (unpinned dependencies)
+- Data exfiltration patterns
+- Social engineering triggers
+- Cross-skill overlap and coordinated behavior
+- Missing metadata (license, provenance)
+
+**Behavior**:
+- **MEDIUM or higher findings** → ❌ Workflow fails, blocks PR merge
+- **LOW/INFO only** → ✅ Workflow passes
+- Posts scan summary as PR comment with collapsible report per pack
+- Uploads detailed reports as workflow artifacts (30-day retention)
+
+**How to run locally**:
+```bash
+# Install scanner
+uv pip install --system 'cisco-ai-skill-scanner[google]'
+
+# Set credentials
+export SKILL_SCANNER_LLM_API_KEY=<your-api-key>
+export SKILL_SCANNER_LLM_MODEL=gemini/gemini-2.5-pro  # or openai/gpt-5
+
+# Scan a single pack
+skill-scanner scan-all rh-virt/skills \
+  --recursive --use-behavioral --use-llm \
+  --check-overlap --enable-meta \
+  --fail-on-severity medium \
+  --format markdown --detailed \
+  --output security-report.md
+```
+
+**Manual workflow dispatch**:
+1. Go to Actions → Skill Security Scan
+2. Click "Run workflow"
+3. Provide:
+   - **PR number** (required) — PR to post results to
+   - **Scan all packs** — `true` for full scan, `false` for changed packs only
+
+**Secrets required**:
+- `SKILL_SCANNER_LLM_API_KEY` — API key for LLM provider
+- `SKILL_SCANNER_LLM_MODEL` — Model identifier (e.g., `gemini/gemini-2.5-pro`)
+
+**Performance**:
+- ~10-15 minutes per pack (depends on number of skills and LLM response time)
+- Uses `uv` instead of `pip` for faster dependency installation with caching
+
+**Related files**:
+- `scripts/detect-changed-packs.sh` - Detects packs with changed files in PRs
+- Security reports uploaded as workflow artifacts
+
+### 5. `gemini-code-review.yml` - Gemini Code Review
+
+**Purpose**: Automated code review using Google Gemini, validating PRs against project rules (CLAUDE.md, SKILL_DESIGN_PRINCIPLES.md).
+
+**Triggers**:
+- **Pull requests** (opened, synchronize, reopened)
+- **Manual dispatch** with PR number
+
+**What it does**:
+- Fetches PR diff and project rules
+- Sends to Gemini for review
+- Posts review as PR comment (updates existing comment on re-runs)
+
+**Secrets required**:
+- `GEMINI_API_KEY` — Google Gemini API key
+
 ## Adding New Workflows
 
 When adding new workflows:
@@ -358,7 +440,5 @@ This README should be updated when:
 - New validation levels are introduced
 - Troubleshooting patterns emerge
 
-**Last Updated**: 2026-02-27
-**Workflows Count**: 3 (skill-spec-report.yml, compliance-check.yml, deploy-pages.yml)
-
-**Note**: `validate-skills.yml` was removed 2026-02-27. Repository-specific design principle validation (Tier 2) will be handled by a separate workflow.
+**Last Updated**: 2026-05-05
+**Workflows Count**: 5 (skill-spec-report.yml, compliance-check.yml, deploy-pages.yml, security-scan.yml, gemini-code-review.yml)
diff --git a/.github/workflows/skill-security-scan.yml b/.github/workflows/skill-security-scan.yml
new file mode 100644
index 00000000..a114d72c
--- /dev/null
+++ b/.github/workflows/skill-security-scan.yml
@@ -0,0 +1,316 @@
+name: Skill Security Scan
+
+on:
+  pull_request:
+    types: [opened, synchronize, reopened, ready_for_review]
+    paths:
+      - '**/skills/**'
+      - '**/mcps.json'
+  workflow_dispatch:
+    inputs:
+      pr_number:
+        description: 'PR number to review'
+        required: true
+        type: number
+      scan_all:
+        description: 'Scan all packs (true) or changed only (false)'
+        required: false
+        default: 'false'
+        type: choice
+        options:
+          - 'true'
+          - 'false'
+
+concurrency:
+  group: security-scan-${{ github.event.pull_request.number || github.run_id }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read
+  pull-requests: write
+  checks: read
+
+jobs:
+  security-scan:
+    if: github.event.pull_request.draft == false || github.event_name == 'workflow_dispatch'
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Resolve PR number
+        id: pr
+        run: |
+          if [ "${{ github.event_name }}" = "workflow_dispatch" ]; then
+            echo "number=${{ inputs.pr_number }}" >> "$GITHUB_OUTPUT"
+          else
+            echo "number=${{ github.event.pull_request.number }}" >> "$GITHUB_OUTPUT"
+          fi
+
+      - name: Wait for prerequisite checks
+        if: github.event_name == 'pull_request'
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const requiredChecks = ['compliance-check', 'skill-linter'];
+            const sha = context.payload.pull_request.head.sha;
+            const maxWait = 300000; // 5 minutes
+            const interval = 15000; // 15 seconds
+            let elapsed = 0;
+
+            core.info(`Waiting for checks on ${sha}: ${requiredChecks.join(', ')}`);
+
+            while (elapsed < maxWait) {
+              const { data: { check_runs } } = await github.rest.checks.listForRef({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                ref: sha,
+              });
+
+              const results = requiredChecks.map(name => {
+                const run = check_runs.find(r => r.name === name);
+                return { name, status: run?.status, conclusion: run?.conclusion };
+              });
+
+              const allCompleted = results.every(r => r.status === 'completed');
+              if (allCompleted) {
+                const failed = results.filter(r => r.conclusion !== 'success');
+                if (failed.length > 0) {
+                  const summary = failed.map(r => `${r.name}: ${r.conclusion}`).join(', ');
+                  core.setFailed(`Prerequisite checks failed (${summary}) — skipping security scan to save tokens`);
+                  return;
+                }
+                core.info('All prerequisite checks passed — proceeding with security scan');
+                return;
+              }
+
+              const pending = results.filter(r => r.status !== 'completed').map(r => r.name);
+              core.info(`Waiting for: ${pending.join(', ')} (${elapsed / 1000}s elapsed)`);
+              await new Promise(r => setTimeout(r, interval));
+              elapsed += interval;
+            }
+
+            core.setFailed('Timed out waiting for prerequisite checks — skipping security scan');
+
+      - name: Set up uv
+        uses: astral-sh/setup-uv@v7
+        with:
+          enable-cache: true
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: '3.11'
+
+      - name: Install skill-scanner
+        run: uv pip install --system 'cisco-ai-skill-scanner[google]'
+
+      - name: Detect changed packs
+        id: detect
+        run: |
+          if [ "${{ github.event_name }}" = "workflow_dispatch" ] && [ "${{ github.event.inputs.scan_all }}" = "true" ]; then
+            PACKS=$(find . -maxdepth 2 -name skills -type d | sed 's|^\./||;s|/skills$||' | sort)
+          else
+            PACKS=$(bash scripts/detect-changed-packs.sh || true)
+          fi
+
+          PACK_COUNT=$(echo "$PACKS" | grep -c . || true)
+
+          if [ -z "$PACKS" ] || [ "$PACK_COUNT" -eq 0 ]; then
+            echo "changed=false" >> $GITHUB_OUTPUT
+            echo "packs=" >> $GITHUB_OUTPUT
+            echo "pack_count=0" >> $GITHUB_OUTPUT
+            echo "No packs with changes detected — skipping security scan"
+          elif [ "$PACK_COUNT" -gt 1 ]; then
+            echo "changed=true" >> $GITHUB_OUTPUT
+            echo "packs<<EOF" >> $GITHUB_OUTPUT
+            echo "$PACKS" >> $GITHUB_OUTPUT
+            echo "EOF" >> $GITHUB_OUTPUT
+            echo "pack_count=$PACK_COUNT" >> $GITHUB_OUTPUT
+            echo "::warning::Multiple packs detected ($PACK_COUNT): $PACKS"
+          else
+            echo "changed=true" >> $GITHUB_OUTPUT
+            echo "packs<<EOF" >> $GITHUB_OUTPUT
+            echo "$PACKS" >> $GITHUB_OUTPUT
+            echo "EOF" >> $GITHUB_OUTPUT
+            echo "pack_count=1" >> $GITHUB_OUTPUT
+            echo "Changed pack detected: $PACKS"
+          fi
+
+      - name: Reject multi-pack PRs
+        if: steps.detect.outputs.changed == 'true' && steps.detect.outputs.pack_count != '1' && github.event_name != 'workflow_dispatch'
+        env:
+          GH_TOKEN: ${{ github.token }}
+        run: |
+          set -euo pipefail
+          MARKER="<!-- skill-security-scan -->"
+          PR_NUMBER="${{ steps.pr.outputs.number }}"
+          PACKS="${{ steps.detect.outputs.packs }}"
+
+          PACK_LIST=""
+          while IFS= read -r pack; do
+            [ -z "$pack" ] && continue
+            PACK_LIST="${PACK_LIST}\n- \`${pack}\`"
+          done <<< "$PACKS"
+
+          {
+            echo "$MARKER"
+            echo "## ⚠️ Skill Security Scan — Skipped"
+            echo ""
+            echo "This PR contains changes in **multiple packs**:"
+            echo -e "$PACK_LIST"
+            echo ""
+            echo "To keep security scans fast and cost-effective, please limit each PR to **one pack only**."
+            echo "Split your changes into separate PRs (one per pack) and the security scan will run automatically."
+          } > /tmp/comment.md
+
+          EXISTING_COMMENT_ID=$(gh api --paginate \
+            "/repos/${{ github.repository }}/issues/${PR_NUMBER}/comments" \
+            --jq ".[] | select(.body | startswith(\"$MARKER\")) | .id" \
+            | head -1)
+
+          if [ -n "$EXISTING_COMMENT_ID" ]; then
+            gh api \
+              --method PATCH \
+              "/repos/${{ github.repository }}/issues/comments/$EXISTING_COMMENT_ID" \
+              -f body="$(cat /tmp/comment.md)"
+          else
+            gh pr comment "$PR_NUMBER" \
+              --repo "${{ github.repository }}" \
+              --body-file /tmp/comment.md
+          fi
+
+          echo "❌ Multiple packs detected — aborting security scan"
+          exit 1
+
+      - name: Check scanner credentials
+        if: steps.detect.outputs.changed == 'true' && steps.detect.outputs.pack_count == '1'
+        id: creds
+        env:
+          SKILL_SCANNER_LLM_API_KEY: ${{ secrets.SKILL_SCANNER_LLM_API_KEY }}
+        run: |
+          if [ -z "$SKILL_SCANNER_LLM_API_KEY" ]; then
+            echo "::warning::SKILL_SCANNER_LLM_API_KEY not available (expected for fork PRs). Skipping security scan."
+            echo "available=false" >> "$GITHUB_OUTPUT"
+          else
+            echo "available=true" >> "$GITHUB_OUTPUT"
+          fi
+
+      - name: Run security scan
+        if: steps.detect.outputs.pack_count == '1' && steps.creds.outputs.available == 'true'
+        id: scan
+        env:
+          SKILL_SCANNER_LLM_API_KEY: ${{ secrets.SKILL_SCANNER_LLM_API_KEY }}
+          SKILL_SCANNER_LLM_MODEL: ${{ secrets.SKILL_SCANNER_LLM_MODEL }}
+        run: |
+          mkdir -p security-reports
+          SCAN_FAILED=false
+
+          while IFS= read -r pack; do
+            [ -z "$pack" ] && continue
+            echo "=== Scanning: $pack ==="
+
+            skill-scanner scan-all "$pack/skills" \
+              --recursive \
+              --use-behavioral \
+              --use-llm \
+              --check-overlap \
+              --enable-meta \
+              --fail-on-severity medium \
+              --format markdown \
+              --detailed \
+              --output "security-reports/security-report-${pack}.md" || SCAN_FAILED=true
+
+            echo ""
+          done <<< "${{ steps.detect.outputs.packs }}"
+
+          if [ "$SCAN_FAILED" = "true" ]; then
+            echo "scan_result=failed" >> $GITHUB_OUTPUT
+          else
+            echo "scan_result=passed" >> $GITHUB_OUTPUT
+          fi
+
+      - name: Upload security reports
+        id: upload
+        if: steps.detect.outputs.pack_count == '1' && steps.creds.outputs.available == 'true' && always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: security-reports
+          path: security-reports/
+          retention-days: 30
+          if-no-files-found: ignore
+
+      - name: Post scan summary
+        if: steps.detect.outputs.pack_count == '1' && steps.creds.outputs.available == 'true' && always()
+        env:
+          GH_TOKEN: ${{ github.token }}
+        run: |
+          set -euo pipefail
+          MARKER="<!-- skill-security-scan -->"
+          SCAN_RESULT="${{ steps.scan.outputs.scan_result }}"
+          ARTIFACT_URL="${{ steps.upload.outputs.artifact-url }}"
+          PR_NUMBER="${{ steps.pr.outputs.number }}"
+
+          if [ "$SCAN_RESULT" = "passed" ]; then
+            ICON="✅"
+          else
+            ICON="❌"
+          fi
+
+          {
+            echo "$MARKER"
+            echo "## $ICON Skill Security Scan"
+            echo ""
+
+            if [ -d "security-reports" ]; then
+              for report in security-reports/security-report-*.md; do
+                [ -f "$report" ] || continue
+                pack=$(basename "$report" .md | sed 's/^security-report-//')
+                echo "<details>"
+                echo "<summary>📋 $pack</summary>"
+                echo ""
+                cat "$report"
+                echo ""
+                echo "</details>"
+                echo ""
+              done
+            else
+              echo "No reports generated."
+            fi
+
+            echo ""
+            if [ -n "$ARTIFACT_URL" ]; then
+              echo "> 📦 [Download security reports]($ARTIFACT_URL) | [Workflow run](${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }})"
+            else
+              echo "> [Workflow run](${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }})"
+            fi
+          } > /tmp/comment.md
+
+          EXISTING_COMMENT_ID=$(gh api --paginate \
+            "/repos/${{ github.repository }}/issues/${PR_NUMBER}/comments" \
+            --jq ".[] | select(.body | startswith(\"$MARKER\")) | .id" \
+            | head -1)
+
+          if [ -n "$EXISTING_COMMENT_ID" ]; then
+            gh api \
+              --method PATCH \
+              "/repos/${{ github.repository }}/issues/comments/$EXISTING_COMMENT_ID" \
+              -f body="$(cat /tmp/comment.md)"
+          else
+            gh pr comment "$PR_NUMBER" \
+              --repo "${{ github.repository }}" \
+              --body-file /tmp/comment.md
+          fi
+
+      - name: Check scan results
+        if: steps.detect.outputs.pack_count == '1' && steps.creds.outputs.available == 'true'
+        run: |
+          if [ "${{ steps.scan.outputs.scan_result }}" = "failed" ]; then
+            echo "❌ Security scan found MEDIUM or higher severity issues — blocking merge"
+            exit 1
+          else
+            echo "✅ Security scan passed — no MEDIUM or higher severity issues found"
+          fi
diff --git a/scripts/detect-changed-packs.sh b/scripts/detect-changed-packs.sh
new file mode 100755
index 00000000..1e539749
--- /dev/null
+++ b/scripts/detect-changed-packs.sh
@@ -0,0 +1,42 @@
+#!/usr/bin/env bash
+# Detect packs with changed files in CI (PRs and pushes to main)
+# Outputs unique pack names (one per line) for security scanning
+# Exits 0 if no packs changed
+#
+# Detects changes in ANY file within a pack directory (skills, mcps.json, docs, etc.)
+
+set -e
+
+if [ -n "$VALIDATE_INCLUDE_UNCOMMITTED" ]; then
+  DIFF_CMD="git diff --name-only HEAD"
+elif [ "$GITHUB_EVENT_NAME" = "pull_request" ]; then
+  BASE_REF="${GITHUB_BASE_REF:-main}"
+  git fetch origin "$BASE_REF" 2>/dev/null || true
+  DIFF_CMD="git diff --name-only origin/$BASE_REF...HEAD"
+elif [ "$GITHUB_EVENT_NAME" = "push" ]; then
+  BEFORE="${GITHUB_EVENT_BEFORE:-}"
+  if [ -z "$BEFORE" ] || [ "$BEFORE" = "0000000000000000000000000000000000000000" ]; then
+    exit 0
+  fi
+  DIFF_CMD="git diff --name-only $BEFORE HEAD"
+else
+  DIFF_CMD="git diff --name-only HEAD"
+fi
+
+CHANGED_FILES=$($DIFF_CMD 2>/dev/null || true)
+
+if [ -z "$CHANGED_FILES" ]; then
+  exit 0
+fi
+
+# Extract pack names: first path component of files that live inside a pack with a skills/ directory
+# Exclude dotfiles (.github, .claude, etc.)
+echo "$CHANGED_FILES" \
+  | grep -v '^\.' \
+  | cut -d'/' -f1 \
+  | sort -u \
+  | while read -r dir; do
+      if [ -d "$dir/skills" ]; then
+        echo "$dir"
+      fi
+    done