diff --git a/internal/config/config.go b/internal/config/config.go
index 1ff0a1f..42d2274 100644
--- a/internal/config/config.go
+++ b/internal/config/config.go
@@ -45,6 +45,22 @@ type ShellConfigSection struct {
 	Blocks []ShellConfigBlock `yaml:"blocks"`
 }
 
+type NeovimConfig struct {
+	NvChadStarterRepo string `yaml:"nvchad_starter_repo"`
+}
+
+type RenodePlatform struct {
+	Name     string `yaml:"name"`
+	ReplPath string `yaml:"repl_path"`
+	Machine  string `yaml:"machine"`
+}
+
+type RenodeConfig struct {
+	WokwiVersion string           `yaml:"wokwi_version"`
+	WokwiURL     string           `yaml:"wokwi_url"`
+	Platforms    []RenodePlatform `yaml:"platforms"`
+}
+
 // Config is the fully-resolved runtime configuration.
 type Config struct {
 	Version         int                `yaml:"version"`
@@ -58,6 +74,8 @@ type Config struct {
 	Zellij          ZellijConfig       `yaml:"zellij"`
 	Themes          ThemesConfig       `yaml:"themes"`
 	ShellConfig     ShellConfigSection `yaml:"shell_config"`
+	Neovim          NeovimConfig       `yaml:"neovim"`
+	Renode          RenodeConfig       `yaml:"renode"`
 }
 
 const currentVersion = 1
@@ -137,5 +155,11 @@ func merge(base, over Config) Config {
 	if len(over.ShellConfig.Blocks) > 0 {
 		out.ShellConfig = over.ShellConfig
 	}
+	if over.Neovim.NvChadStarterRepo != "" {
+		out.Neovim = over.Neovim
+	}
+	if over.Renode.WokwiVersion != "" || len(over.Renode.Platforms) > 0 {
+		out.Renode = over.Renode
+	}
 	return out
 }
diff --git a/internal/config/config_test.go b/internal/config/config_test.go
index db6cf95..4becd3c 100644
--- a/internal/config/config_test.go
+++ b/internal/config/config_test.go
@@ -73,6 +73,31 @@ func TestDefaultsCarryModuleInputs(t *testing.T) {
 	}
 }
 
+func TestDefaultsCarryPlan3bInputs(t *testing.T) {
+	cfg, err := Load("/nonexistent/overlay.yaml")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if cfg.Neovim.NvChadStarterRepo == "" {
+		t.Error("Neovim.NvChadStarterRepo empty")
+	}
+	if cfg.Renode.WokwiVersion == "" {
+		t.Error("Renode.WokwiVersion empty")
+	}
+	if cfg.Renode.WokwiURL == "" {
+		t.Error("Renode.WokwiURL empty")
+	}
+	if len(cfg.Renode.Platforms) == 0 {
+		t.Error("Renode.Platforms empty")
+	}
+	want := map[string]string{"stm32f4": "STM32F4_Discovery", "rp2040": "RP2040", "nrf52840": "nRF52840"}
+	for _, p := range cfg.Renode.Platforms {
+		if want[p.Name] != p.Machine {
+			t.Errorf("platform %q: machine=%q want %q", p.Name, p.Machine, want[p.Name])
+		}
+	}
+}
+
 func TestLoadRejectsUnknownVersion(t *testing.T) {
 	dir := t.TempDir()
 	path := filepath.Join(dir, "overlay.yaml")
diff --git a/internal/config/defaults.yaml b/internal/config/defaults.yaml
index ff2bc1f..f609072 100644
--- a/internal/config/defaults.yaml
+++ b/internal/config/defaults.yaml
@@ -80,3 +80,20 @@ shell_config:
         alias v="nvim"
         alias y="yazi"
         alias theme="archduino-theme"
+
+neovim:
+  nvchad_starter_repo: "https://github.com/NvChad/starter"
+
+renode:
+  wokwi_version: "0.28.1"
+  wokwi_url: "https://github.com/wokwi/wokwi-cli/releases/download/v0.28.1/wokwi-cli-linuxstatic-x64"
+  platforms:
+    - name: stm32f4
+      repl_path: "platforms/boards/stm32f4_discovery.repl"
+      machine: "STM32F4_Discovery"
+    - name: rp2040
+      repl_path: "platforms/cpus/rp2040.repl"
+      machine: "RP2040"
+    - name: nrf52840
+      repl_path: "platforms/cpus/nrf52840.repl"
+      machine: "nRF52840"