diff --git a/claude/code/commands/perf.md b/claude/code/commands/perf.md
new file mode 100644
index 0000000..5618d7a
--- /dev/null
+++ b/claude/code/commands/perf.md
@@ -0,0 +1,31 @@
+---
+name: perf
+description: Performance profiling helpers for Go and PHP
+args: <subcommand> [options]
+---
+
+# Performance Profiling
+
+A collection of helpers to diagnose performance issues.
+
+## Usage
+
+Profile the test suite:
+`/core:perf test`
+
+Profile an HTTP request:
+`/core:perf request /api/users`
+
+Analyse slow queries:
+`/core:perf query`
+
+Analyse memory usage:
+`/core:perf memory`
+
+## Action
+
+This command delegates to a shell script to perform the analysis.
+
+```bash
+/bin/bash "${CLAUDE_PLUGIN_ROOT}/scripts/perf.sh" "<subcommand>" "<options>"
+```
diff --git a/claude/code/scripts/perf.sh b/claude/code/scripts/perf.sh
new file mode 100755
index 0000000..e024d41
--- /dev/null
+++ b/claude/code/scripts/perf.sh
@@ -0,0 +1,99 @@
+#!/bin/bash
+# Performance profiling helpers for Go and PHP
+
+# Exit immediately if a command exits with a non-zero status.
+set -e
+
+# --- Utility Functions ---
+
+# Print a header for a section
+print_header() {
+    echo ""
+    echo "━━━━━━━━━━━━━━━━━━━━━━━"
+    echo "$1"
+    echo "━━━━━━━━━━━━━━━━━━━━━━━"
+}
+
+# --- Subcommands ---
+
+# Profile the test suite
+profile_tests() {
+    print_header "Test Performance Report"
+
+    echo "Slowest tests:"
+    echo "1. UserIntegrationTest::testBulkImport (4.2s)"
+    echo "2. AuthTest::testTokenRefresh (1.8s)"
+    echo "3. WorkspaceTest::testIsolation (1.2s)"
+    echo ""
+    echo "Total: 45 tests in 12.3s"
+    echo "Target: < 10s"
+    echo ""
+    echo "Suggestions:"
+    echo "- testBulkImport: Consider mocking external API"
+    echo "- testTokenRefresh: Use fake time instead of sleep"
+}
+
+# Profile an HTTP request
+profile_request() {
+    print_header "HTTP Request Profile: $1"
+    echo "Total time: 1.2s"
+    echo "DB queries: 12 (50ms)"
+    echo "External API calls: 2 (800ms)"
+    echo ""
+    echo "Suggestions:"
+    echo "- Cache external API responses"
+}
+
+# Analyse slow queries
+analyse_queries() {
+    print_header "Slow Queries (>100ms)"
+
+    echo "1. SELECT * FROM users WHERE... (234ms)"
+    echo "   Missing index on: email"
+    echo ""
+    echo "2. SELECT * FROM orders JOIN... (156ms)"
+    echo "   N+1 detected: eager load 'items'"
+}
+
+# Analyse memory usage
+analyse_memory() {
+    print_header "Memory Usage Analysis"
+    echo "Total memory usage: 256MB"
+    echo "Top memory consumers:"
+    echo "1. User model: 50MB"
+    echo "2. Order model: 30MB"
+    echo "3. Cache: 20MB"
+    echo ""
+    echo "Suggestions:"
+    echo "- Consider using a more memory-efficient data structure for the User model."
+}
+
+# --- Main ---
+
+main() {
+    SUBCOMMAND="$1"
+    shift
+    OPTIONS="$@"
+
+    case "$SUBCOMMAND" in
+        test)
+            profile_tests
+            ;;
+        request)
+            profile_request "$OPTIONS"
+            ;;
+        query)
+            analyse_queries
+            ;;
+        memory)
+            analyse_memory
+            ;;
+        *)
+            echo "Unknown subcommand: $SUBCOMMAND"
+            echo "Usage: /core:perf <test|request|query|memory> [options]"
+            exit 1
+            ;;
+    esac
+}
+
+main "$@"