fix: tests

Author: Savid

internal/config/capability.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 
 	sdkerrors "github.com/ethpandaops/codex-agent-sdk-go/internal/errors"
+	"github.com/ethpandaops/codex-agent-sdk-go/internal/mcp"
 )
 
 // QueryBackend describes the built-in backend selected for one-shot Query.
@@ -187,6 +188,12 @@ func SelectQueryBackend(opts *Options) QueryBackend {
 		return QueryBackendExec
 	}
 
+	// SDK MCP servers require bidirectional callbacks and cannot be serialized
+	// to exec CLI flags, so Query must run over app-server mode.
+	if hasSDKMCPServers(opts.MCPServers) {
+		return QueryBackendAppServer
+	}
+
 	enabled := EnabledOptionFields(opts)
 	for field := range enabled {
 		capability, ok := optionCapabilityByField[field]
@@ -209,6 +216,14 @@ func ValidateOptionsForBackend(opts *Options, backend QueryBackend) error {
 		return nil
 	}
 
+	if backend == QueryBackendExec && hasSDKMCPServers(opts.MCPServers) {
+		return fmt.Errorf(
+			"%w: option MCPServers (WithMCPServers) with SDK server type is unsupported on %s backend",
+			sdkerrors.ErrUnsupportedOption,
+			backend,
+		)
+	}
+
 	enabled := EnabledOptionFields(opts)
 	for field := range enabled {
 		capability, ok := optionCapabilityByField[field]
@@ -257,3 +272,21 @@ func ValidateOptionsForBackend(opts *Options, backend QueryBackend) error {
 
 	return nil
 }
+
+func hasSDKMCPServers(servers map[string]mcp.ServerConfig) bool {
+	if len(servers) == 0 {
+		return false
+	}
+
+	for _, server := range servers {
+		if server == nil {
+			continue
+		}
+
+		if server.GetType() == mcp.ServerTypeSDK {
+			return true
+		}
+	}
+
+	return false
+}

internal/config/capability_test.go

@@ -5,6 +5,7 @@ import (
 	"testing"
 
 	"github.com/ethpandaops/codex-agent-sdk-go/internal/hook"
+	"github.com/ethpandaops/codex-agent-sdk-go/internal/mcp"
 	"github.com/stretchr/testify/require"
 )
 
@@ -64,6 +65,24 @@ func TestSelectQueryBackend(t *testing.T) {
 			},
 			want: QueryBackendAppServer,
 		},
+		{
+			name: "SDK MCP server requires app-server",
+			options: &Options{
+				MCPServers: map[string]mcp.ServerConfig{
+					"sdk": &mcp.SdkServerConfig{Type: mcp.ServerTypeSDK, Name: "sdk"},
+				},
+			},
+			want: QueryBackendAppServer,
+		},
+		{
+			name: "non-SDK MCP server keeps exec",
+			options: &Options{
+				MCPServers: map[string]mcp.ServerConfig{
+					"stdio": &mcp.StdioServerConfig{Command: "echo"},
+				},
+			},
+			want: QueryBackendExec,
+		},
 	}
 
 	for _, tt := range tests {
@@ -129,4 +148,18 @@ func TestValidateOptionsForBackend(t *testing.T) {
 		require.Error(t, err)
 		require.ErrorContains(t, err, "only supports value \"stdio\"")
 	})
+
+	t.Run("exec backend rejects SDK MCP servers", func(t *testing.T) {
+		t.Parallel()
+
+		opts := &Options{
+			MCPServers: map[string]mcp.ServerConfig{
+				"sdk": &mcp.SdkServerConfig{Type: mcp.ServerTypeSDK, Name: "sdk"},
+			},
+		}
+
+		err := ValidateOptionsForBackend(opts, QueryBackendExec)
+		require.Error(t, err)
+		require.ErrorContains(t, err, "MCPServers")
+	})
 }

query_test.go

@@ -402,6 +402,15 @@ func TestRequiresAppServerQuery(t *testing.T) {
 		{name: "fork requires app-server", options: &CodexAgentOptions{ForkSession: true}, want: true},
 		{name: "continue requires app-server", options: &CodexAgentOptions{ContinueConversation: true}, want: true},
 		{name: "output format requires app-server", options: &CodexAgentOptions{OutputFormat: map[string]any{"type": "json_schema"}}, want: true},
+		{
+			name: "sdk mcp server requires app-server",
+			options: &CodexAgentOptions{
+				MCPServers: map[string]MCPServerConfig{
+					"sdk": &MCPSdkServerConfig{Type: MCPServerTypeSDK, Name: "sdk"},
+				},
+			},
+			want: true,
+		},
 	}
 
 	for _, tt := range tests {