diff --git a/internal/agents/antigravity/adapter.go b/internal/agents/antigravity/adapter.go
index bad5a8298..2705e9ea8 100644
--- a/internal/agents/antigravity/adapter.go
+++ b/internal/agents/antigravity/adapter.go
@@ -105,7 +105,8 @@ func (a *Adapter) MCPStrategy() model.MCPStrategy {
 // --- MCP ---
 
 func (a *Adapter) MCPConfigPath(homeDir string, _ string) string {
-	return filepath.Join(a.antigravityVariantDir(homeDir), "mcp_config.json")
+	// Antigravity uses a shared global config for MCP across CLI, Desktop, and IDE.
+	return filepath.Join(homeDir, ".gemini", "config", "mcp_config.json")
 }
 
 // --- Optional capabilities ---
diff --git a/internal/agents/antigravity/adapter_test.go b/internal/agents/antigravity/adapter_test.go
index 3813b704d..939fbdd30 100644
--- a/internal/agents/antigravity/adapter_test.go
+++ b/internal/agents/antigravity/adapter_test.go
@@ -174,8 +174,9 @@ func TestConfigPathsCLIOnly(t *testing.T) {
 	if got := a.SettingsPath(home); got != filepath.Join(cliDir, "settings.json") {
 		t.Fatalf("SettingsPath() = %q, want %q", got, filepath.Join(cliDir, "settings.json"))
 	}
-	if got := a.MCPConfigPath(home, "ctx7"); got != filepath.Join(cliDir, "mcp_config.json") {
-		t.Fatalf("MCPConfigPath() = %q, want %q", got, filepath.Join(cliDir, "mcp_config.json"))
+	wantMCP := filepath.Join(home, ".gemini", "config", "mcp_config.json")
+	if got := a.MCPConfigPath(home, "ctx7"); got != wantMCP {
+		t.Fatalf("MCPConfigPath() = %q, want %q", got, wantMCP)
 	}
 }
 
@@ -193,8 +194,9 @@ func TestConfigPathsDesktopOnly(t *testing.T) {
 	if got := a.SettingsPath(home); got != filepath.Join(desktopDir, "settings.json") {
 		t.Fatalf("SettingsPath() = %q, want %q", got, filepath.Join(desktopDir, "settings.json"))
 	}
-	if got := a.MCPConfigPath(home, "ctx7"); got != filepath.Join(desktopDir, "mcp_config.json") {
-		t.Fatalf("MCPConfigPath() = %q, want %q", got, filepath.Join(desktopDir, "mcp_config.json"))
+	wantMCP := filepath.Join(home, ".gemini", "config", "mcp_config.json")
+	if got := a.MCPConfigPath(home, "ctx7"); got != wantMCP {
+		t.Fatalf("MCPConfigPath() = %q, want %q", got, wantMCP)
 	}
 }
 
diff --git a/internal/components/engram/inject_test.go b/internal/components/engram/inject_test.go
index 488064f5e..aacb39ceb 100644
--- a/internal/components/engram/inject_test.go
+++ b/internal/components/engram/inject_test.go
@@ -557,7 +557,7 @@ func TestInjectGeminiToolsFlagPresent(t *testing.T) {
 	}
 }
 
-func TestInjectAntigravityWritesMCPToCLIConfig(t *testing.T) {
+func TestInjectAntigravityWritesMCPToGlobalConfig(t *testing.T) {
 	home := t.TempDir()
 
 	result, err := Inject(home, antigravityAdapter())
@@ -568,10 +568,10 @@ func TestInjectAntigravityWritesMCPToCLIConfig(t *testing.T) {
 		t.Fatalf("Inject(antigravity) changed = false")
 	}
 
-	cliMCPPath := filepath.Join(home, ".gemini", "antigravity-cli", "mcp_config.json")
-	content, err := os.ReadFile(cliMCPPath)
+	globalMCPPath := filepath.Join(home, ".gemini", "config", "mcp_config.json")
+	content, err := os.ReadFile(globalMCPPath)
 	if err != nil {
-		t.Fatalf("ReadFile(%q) error = %v", cliMCPPath, err)
+		t.Fatalf("ReadFile(%q) error = %v", globalMCPPath, err)
 	}
 	text := string(content)
 	if !strings.Contains(text, `"args": [`) || !strings.Contains(text, `"mcp"`) {
diff --git a/internal/components/golden_test.go b/internal/components/golden_test.go
index 2589cd7da..fc813b05f 100644
--- a/internal/components/golden_test.go
+++ b/internal/components/golden_test.go
@@ -896,8 +896,8 @@ func TestGoldenEngram_Antigravity(t *testing.T) {
 		t.Fatalf("engram.Inject(antigravity) changed = false")
 	}
 
-	// MCP config written to ~/.gemini/antigravity-cli/mcp_config.json.
-	mcpJSON := readTestFile(t, filepath.Join(home, ".gemini", "antigravity-cli", "mcp_config.json"))
+	// MCP config written to ~/.gemini/config/mcp_config.json.
+	mcpJSON := readTestFile(t, filepath.Join(home, ".gemini", "config", "mcp_config.json"))
 	assertGolden(t, "engram-antigravity-mcp.golden", mcpJSON)
 
 	// GEMINI.md must contain the engram-protocol section.