Warn when CLI is older than API minimum version

internal/api/client.go

@@ -5,13 +5,30 @@ import (
 	"crypto/tls"
 	"fmt"
 	"net/http"
+	"sync"
 	"time"
 
 	notteErrors "github.com/nottelabs/notte-cli/internal/errors"
+	"github.com/nottelabs/notte-cli/internal/update"
 )
 
 const DefaultBaseURL = "https://api.notte.cc"
 
+// MinCLIVersionHeader is the response header the API uses to advertise the
+// minimum CLI version required for full compatibility.
+const MinCLIVersionHeader = "x-notte-min-cli-version"
+
+// detectedMinVersion stores the minimum CLI version returned by the API.
+// Set once by checkMinVersion; read by root.go to trigger the upgrade prompt.
+var detectedMinVersion string
+var detectOnce sync.Once
+
+// DetectedMinVersion returns the API-required minimum CLI version, or "" if
+// the header was not seen or the CLI is already up to date.
+func DetectedMinVersion() string {
+	return detectedMinVersion
+}
+
 // NotteClient wraps the generated client with auth and resilience
 type NotteClient struct {
 	client         *ClientWithResponses
@@ -142,9 +159,29 @@ func (t *resilientTransport) RoundTrip(req *http.Request) (*http.Response, error
 		t.circuitBreaker.RecordSuccess()
 	}
 
+	// Check if the API requires a newer CLI version
+	t.checkMinVersion(resp)
+
 	return resp, nil
 }
 
+// checkMinVersion inspects the x-notte-min-cli-version response header and
+// stores the required version so the root command can prompt for upgrade.
+func (t *resilientTransport) checkMinVersion(resp *http.Response) {
+	minVersion := resp.Header.Get(MinCLIVersionHeader)
+	if minVersion == "" || t.version == "" || t.version == "dev" {
+		return
+	}
+
+	detectOnce.Do(func() {
+		outdated, err := update.IsNewer(t.version, minVersion)
+		if err != nil || !outdated {
+			return
+		}
+		detectedMinVersion = minVersion
+	})
+}
+
 func (t *resilientTransport) doWithRetry(req *http.Request) (*http.Response, error) {
 	var resp *http.Response
 	var err error

internal/api/client_test.go

@@ -7,6 +7,7 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"strings"
+	"sync"
 	"testing"
 	"time"
 )
@@ -389,6 +390,69 @@ func TestNotteClient_APIKey(t *testing.T) {
 	}
 }
 
+func resetDetectOnce() {
+	detectOnce = sync.Once{}
+	detectedMinVersion = ""
+}
+
+func TestCheckMinVersion_StoresWhenOutdated(t *testing.T) {
+	resetDetectOnce()
+	t.Cleanup(resetDetectOnce)
+
+	rt := &resilientTransport{version: "0.0.10"}
+	resp := &http.Response{
+		Header: http.Header{"X-Notte-Min-Cli-Version": []string{"0.0.12"}},
+	}
+	rt.checkMinVersion(resp)
+
+	if got := DetectedMinVersion(); got != "0.0.12" {
+		t.Errorf("DetectedMinVersion() = %q, want %q", got, "0.0.12")
+	}
+}
+
+func TestCheckMinVersion_EmptyWhenCurrent(t *testing.T) {
+	resetDetectOnce()
+	t.Cleanup(resetDetectOnce)
+
+	rt := &resilientTransport{version: "0.0.12"}
+	resp := &http.Response{
+		Header: http.Header{"X-Notte-Min-Cli-Version": []string{"0.0.12"}},
+	}
+	rt.checkMinVersion(resp)
+
+	if got := DetectedMinVersion(); got != "" {
+		t.Errorf("DetectedMinVersion() = %q, want empty", got)
+	}
+}
+
+func TestCheckMinVersion_EmptyWhenNoHeader(t *testing.T) {
+	resetDetectOnce()
+	t.Cleanup(resetDetectOnce)
+
+	rt := &resilientTransport{version: "0.0.10"}
+	resp := &http.Response{Header: http.Header{}}
+	rt.checkMinVersion(resp)
+
+	if got := DetectedMinVersion(); got != "" {
+		t.Errorf("DetectedMinVersion() = %q, want empty", got)
+	}
+}
+
+func TestCheckMinVersion_EmptyForDevVersion(t *testing.T) {
+	resetDetectOnce()
+	t.Cleanup(resetDetectOnce)
+
+	rt := &resilientTransport{version: "dev"}
+	resp := &http.Response{
+		Header: http.Header{"X-Notte-Min-Cli-Version": []string{"0.0.12"}},
+	}
+	rt.checkMinVersion(resp)
+
+	if got := DetectedMinVersion(); got != "" {
+		t.Errorf("DetectedMinVersion() = %q, want empty", got)
+	}
+}
+
 func TestDefaultContext(t *testing.T) {
 	ctx := DefaultContext()
 	if ctx == nil {

internal/cmd/root.go

@@ -54,8 +54,15 @@ func Execute() {
 
 	err := rootCmd.Execute()
 
-	// Show update notification after command output
-	if checker != nil {
+	// If the API told us our CLI is too old, prompt to upgrade (takes priority)
+	if minVer := api.DetectedMinVersion(); minVer != "" {
+		update.PrintUpdateNotification(&update.Result{
+			CurrentVersion:  Version,
+			LatestVersion:   minVer,
+			UpdateAvailable: true,
+		}, os.Stderr, os.Stdin, yesFlag, IsJSONOutput(), noColor)
+	} else if checker != nil {
+		// Otherwise fall back to the GitHub-based update check
 		if result := checker.GetResult(); result != nil {
 			update.PrintUpdateNotification(result, os.Stderr, os.Stdin, yesFlag, IsJSONOutput(), noColor)
 		}