diff --git a/.claude/hooks/session-start.sh b/.claude/hooks/session-start.sh
new file mode 100755
index 0000000..7aac33d
--- /dev/null
+++ b/.claude/hooks/session-start.sh
@@ -0,0 +1,31 @@
+#!/bin/bash
+# SessionStart hook — install the endocrine toolchains so the project's tests run
+# in Claude Code on the web:
+#   * R (Rscript)      -> the Drive-Box drivers + tests  (src/endocrine/*.R)
+#   * GNU Octave       -> the ETR torus + tests          (src/endocrine/etr/*.m)
+#
+# Synchronous + idempotent (safe to re-run; installs only what's missing).
+# Ada/Alire (mafiabot_core) is intentionally NOT installed here: it is not an apt
+# package (the CI uses the setup-alire action) and its CI is scheduled-only. Add
+# it if you want web sessions to build/test the Ada side.
+set -euo pipefail
+
+# Only do the heavy apt install in the remote (web) environment.
+if [ "${CLAUDE_CODE_REMOTE:-}" != "true" ]; then
+  exit 0
+fi
+
+export DEBIAN_FRONTEND=noninteractive
+
+pkgs=()
+command -v Rscript >/dev/null 2>&1 || pkgs+=(r-base-core)
+command -v octave  >/dev/null 2>&1 || pkgs+=(octave)
+
+if [ "${#pkgs[@]}" -gt 0 ]; then
+  sudo apt-get update -qq
+  sudo apt-get install -y --no-install-recommends "${pkgs[@]}"
+fi
+
+# Surface versions in the session log (non-fatal).
+command -v Rscript    >/dev/null 2>&1 && Rscript --version 2>&1 | head -1 || true
+command -v octave-cli >/dev/null 2>&1 && octave-cli --version 2>&1 | head -1 || true
diff --git a/.claude/settings.json b/.claude/settings.json
new file mode 100644
index 0000000..e06b033
--- /dev/null
+++ b/.claude/settings.json
@@ -0,0 +1,14 @@
+{
+  "hooks": {
+    "SessionStart": [
+      {
+        "hooks": [
+          {
+            "type": "command",
+            "command": "$CLAUDE_PROJECT_DIR/.claude/hooks/session-start.sh"
+          }
+        ]
+      }
+    ]
+  }
+}