feat(tokens): refuse minting mcp scopes without the MCP licence feature

server/internal/api/tokens.go

@@ -4,10 +4,12 @@ import (
 	"errors"
 	"fmt"
 	"net/http"
+	"strings"
 
 	"gitea.hostxtra.co.uk/mrhid6/vantage/server/internal/auth"
 	"gitea.hostxtra.co.uk/mrhid6/vantage/server/internal/models"
 	"gitea.hostxtra.co.uk/mrhid6/vantage/server/internal/services"
+	"gitea.hostxtra.co.uk/vantage/vantage-shared/license"
 	"github.com/gin-gonic/gin"
 )
 
@@ -109,6 +111,30 @@ func createToken(c *gin.Context) {
 		}
 	}
 
+	// The MCP scopes are refused without the licence feature, matching the
+	// guard-at-source thinking in services/packages.go rather than relying on
+	// RequireFeature at the /api/mcp group alone. That gate is a runtime one:
+	// without this, a licence downgrade leaves live agent credentials that
+	// authenticate, list as MCP tokens in the UI, and then fail mid-
+	// conversation with a 403 the model cannot explain. Refusing at minting
+	// means a token carrying mcp:* only ever existed while the feature did.
+	//
+	// Existing tokens are deliberately untouched by a downgrade: the route
+	// gate already stops them reaching the endpoint, and silently revoking
+	// credentials on a billing change is worse than refusing new ones.
+	if !services.GetLicenseState(auth.InstanceID(c)).Feature(license.FeatureMCP) {
+		for _, s := range body.Scopes {
+			if strings.HasPrefix(s, "mcp:") {
+				c.JSON(http.StatusForbidden, gin.H{
+					"error":   "feature_unavailable",
+					"feature": license.FeatureMCP,
+					"code":    "feature_unavailable",
+				})
+				return
+			}
+		}
+	}
+
 	if !services.SelectorNarrowerOrEqual(body.TagSelector, auth.ServerScope(c)) {
 		c.JSON(http.StatusForbidden, gin.H{
 			"error": "a token cannot reach servers its creator cannot reach",