diff --git a/.claude/hooks/session-start.sh b/.claude/hooks/session-start.sh
new file mode 100755
index 0000000..ad2fab0
--- /dev/null
+++ b/.claude/hooks/session-start.sh
@@ -0,0 +1,25 @@
+#!/bin/bash
+set -euo pipefail
+
+# Only run in Claude Code on the web; skip on local machines.
+if [ "${CLAUDE_CODE_REMOTE:-}" != "true" ]; then
+  exit 0
+fi
+
+cd "${CLAUDE_PROJECT_DIR:-$(pwd)}"
+
+echo "[openboot session-start] Go version: $(go version)"
+
+# Pre-fetch and verify Go module deps so tests/builds are fast and offline-safe.
+echo "[openboot session-start] Downloading Go modules..."
+go mod download
+
+# Warm the build cache so the first `go build` / `go test` is fast.
+echo "[openboot session-start] Warming build cache (go build ./...)..."
+go build ./... >/dev/null
+
+# Warm the test binary cache without executing tests.
+echo "[openboot session-start] Warming test cache (go test -count=0 ./...)..."
+go test -count=0 ./... >/dev/null
+
+echo "[openboot session-start] Done."
diff --git a/.claude/settings.json b/.claude/settings.json
new file mode 100644
index 0000000..e06b033
--- /dev/null
+++ b/.claude/settings.json
@@ -0,0 +1,14 @@
+{
+  "hooks": {
+    "SessionStart": [
+      {
+        "hooks": [
+          {
+            "type": "command",
+            "command": "$CLAUDE_PROJECT_DIR/.claude/hooks/session-start.sh"
+          }
+        ]
+      }
+    ]
+  }
+}
diff --git a/.gitignore b/.gitignore
index 02b4404..c1a64f7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -30,7 +30,10 @@ __pycache__/
 
 # Work tracking (internal)
 .sisyphus/
-.claude/
+.claude/*
+!.claude/hooks/
+!.claude/settings.json
+.claude/settings.local.json
 
 # Go vendor (deps downloaded at build time)
 vendor/