diff --git a/internal/bundler/bundler.go b/internal/bundler/bundler.go
index e4543964..6a91748c 100644
--- a/internal/bundler/bundler.go
+++ b/internal/bundler/bundler.go
@@ -74,6 +74,10 @@ func bundleJavascript(ctx BundleContext, dir string, outdir string, theproject *
 		ctx.Logger.Debug("installed dependencies: %s", strings.TrimSpace(string(out)))
 	}
 
+	if err := checkForBreakingChanges(ctx, "javascript", theproject.Bundler.Runtime); err != nil {
+		return err
+	}
+
 	var entryPoints []string
 	entryPoints = append(entryPoints, filepath.Join(dir, "index.js"))
 	files, err := util.ListDir(filepath.Join(dir, theproject.Bundler.AgentConfig.Dir))
@@ -192,6 +196,10 @@ func bundlePython(ctx BundleContext, dir string, outdir string, theproject *proj
 		ctx.Logger.Debug("installed dependencies: %s", strings.TrimSpace(string(out)))
 	}
 
+	if err := checkForBreakingChanges(ctx, "python", theproject.Bundler.Runtime); err != nil {
+		return err
+	}
+
 	config := map[string]any{
 		"agents":      getAgents(theproject, "agent.py"),
 		"cli_version": Version,
diff --git a/internal/bundler/upgrade.go b/internal/bundler/upgrade.go
new file mode 100644
index 00000000..2a9c4dfe
--- /dev/null
+++ b/internal/bundler/upgrade.go
@@ -0,0 +1,78 @@
+package bundler
+
+import (
+	"encoding/json"
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/Masterminds/semver"
+	"github.com/agentuity/cli/internal/util"
+	"github.com/agentuity/go-common/tui"
+)
+
+var jsSDKVersion = ">=0.0.106"
+
+type breakingChange struct {
+	Title   string
+	Message string
+	Runtime string
+	Version string
+}
+
+var jsBreakingChanges = []breakingChange{
+	{
+		Runtime: "bunjs",
+		Version: "<0.0.106",
+		Title:   "🚫 JS SDK Breaking Change 🚫",
+		Message: "The JS SDK type signatures for AgentRequest have changed to be async functions. Please see the v0.0.106 Changelog for how to update your code.\n\n" + tui.Link("https://agentuity.dev/Changelog/sdk-js#v00106") + "\n\nPlease bun upgrade @agentuity/sdk, fix your types and ensure your code passes type checking and then re-run this command again.",
+	},
+	{
+		Runtime: "nodejs",
+		Version: "<0.0.106",
+		Title:   "🚫 JS SDK Breaking Change 🚫",
+		Message: "The JS SDK type signatures for AgentRequest have changed to be async functions. Please see the v0.0.106 Changelog for how to update your code.\n\n" + tui.Link("https://agentuity.dev/Changelog/sdk-js#v00106") + "\n\nPlease npm upgrade @agentuity/sdk, fix your types and ensure your code passes type checking and then re-run this command again.",
+	},
+}
+
+type packageJSON struct {
+	Version string `json:"version"`
+}
+
+func checkForBreakingChanges(ctx BundleContext, language string, runtime string) error {
+	switch language {
+	case "javascript":
+		pkgjson := filepath.Join(ctx.ProjectDir, "node_modules", "@agentuity", "sdk", "package.json")
+		if util.Exists(pkgjson) {
+			var pkg packageJSON
+			content, err := os.ReadFile(pkgjson)
+			if err != nil {
+				return err
+			}
+			if err := json.Unmarshal(content, &pkg); err != nil {
+				return err
+			}
+			currentVersion := semver.MustParse(pkg.Version)
+			for _, change := range jsBreakingChanges {
+				if change.Runtime != runtime {
+					continue
+				}
+				c, err := semver.NewConstraint(change.Version)
+				if err != nil {
+					return fmt.Errorf("error parsing semver constraint %s: %w", change.Version, err)
+				}
+				if c.Check(currentVersion) {
+					if tui.HasTTY {
+						tui.ShowBanner(change.Title, change.Message, true)
+						os.Exit(1)
+					} else {
+						ctx.Logger.Fatal(change.Message)
+					}
+				}
+			}
+		}
+	default:
+		return nil
+	}
+	return nil
+}