diff --git a/CLAUDE.md b/CLAUDE.md
index 622589d..5b60dac 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -81,7 +81,7 @@ Each module has a single responsibility. No classes — only exported async func
 
 - Image: `ubuntu:24.04`
 - User: `ubuntu`
-- Memory limit: configurable via `sandlot config memory` (default 32G)
+- Memory limit: configurable via `sandlot config memory` (default 16G)
 - Mounts: `~/dev` **read-only** at `/host`, `~/.sandlot` read-write at `/sandlot`
 - Host symlinks: creates `~/dev` → `/host` and `~/.sandlot` → `/sandlot` inside the container so host-absolute worktree paths resolve correctly
 - `containerPath()` in `vm.ts` translates host paths to container paths (`~/.sandlot/…` → `/sandlot/…`, `~/dev/…` → `/host/…`)
diff --git a/src/commands/config.ts b/src/commands/config.ts
index ad3471d..b084c7d 100644
--- a/src/commands/config.ts
+++ b/src/commands/config.ts
@@ -4,11 +4,6 @@ import * as config from "../config.ts"
 const VALID_KEYS = ["memory"] as const
 type Key = (typeof VALID_KEYS)[number]
 
-function validateMemory(v: string): string {
-  if (!/^[1-9]\d*[GMgm]$/.test(v)) die("Must be a number followed by G or M (e.g. 16G)")
-  return v.toUpperCase()
-}
-
 export async function action(args: string[]) {
   if (args.length === 0) {
     const cfg = await config.load()
@@ -31,9 +26,15 @@ export async function action(args: string[]) {
 
   if (rest.length > 1) die(`Too many arguments. Usage: sandlot config ${key} <value>`)
 
-  if (key === "memory") {
-    const normalized = validateMemory(rest[0])
-    await config.set("memory", normalized)
-    console.log(`memory = ${normalized}`)
+  switch (key) {
+    case "memory": {
+      let normalized: string
+      try { normalized = config.validateMemory(rest[0]) } catch { die("Must be a number followed by G or M (e.g. 16G)") }
+      await config.set("memory", normalized!)
+      console.log(`memory = ${normalized!}`)
+      break
+    }
+    default:
+      die(`Unhandled config key: ${key}`)
   }
 }
diff --git a/src/config.ts b/src/config.ts
index 437b9e9..6c75bef 100644
--- a/src/config.ts
+++ b/src/config.ts
@@ -12,12 +12,21 @@ export interface Config {
   memory?: string
 }
 
+export function validateMemory(v: string): string {
+  if (!/^[1-9]\d*[GMgm]$/.test(v)) throw new Error(`Invalid memory value: ${v} (must be a number followed by G or M, e.g. 16G)`)
+  return v.toUpperCase()
+}
+
 export async function load(): Promise<Config> {
   const file = Bun.file(CONFIG_PATH)
   if (!(await file.exists())) return {}
-  const raw = await file.json()
-  if (typeof raw !== "object" || raw === null || Array.isArray(raw)) return {}
-  return raw as Config
+  try {
+    const raw = await file.json()
+    if (typeof raw !== "object" || raw === null || Array.isArray(raw)) return {}
+    return raw as Config
+  } catch {
+    return {}
+  }
 }
 
 export async function save(config: Config): Promise<void> {
diff --git a/src/vm.ts b/src/vm.ts
index b284313..3302469 100644
--- a/src/vm.ts
+++ b/src/vm.ts
@@ -4,7 +4,7 @@ import { homedir } from "os"
 import { dirname, join } from "path"
 import { requireApiKey } from "./env.ts"
 import { info } from "./fmt.ts"
-import { get as getConfig, DEFAULTS } from "./config.ts"
+import { get as getConfig, DEFAULTS, validateMemory } from "./config.ts"
 
 const DEBUG = !!process.env.DEBUG
 const CONTAINER_NAME = "sandlot"
@@ -67,7 +67,9 @@ function hostMounts(home: string): { dev: boolean; code: boolean } {
 /** Pull the image and start the container in detached mode. */
 async function createContainer(home: string): Promise<void> {
   const mounts = hostMounts(home)
-  const memory = (await getConfig("memory")) ?? DEFAULTS.memory
+  const raw = (await getConfig("memory")) ?? DEFAULTS.memory
+  let memory: string
+  try { memory = validateMemory(raw) } catch { memory = DEFAULTS.memory }
   const args = ["container", "run", "-d", "--name", CONTAINER_NAME, "-m", memory]
   if (mounts.dev) args.push("--mount", `type=bind,source=${home}/dev,target=/host/dev,readonly`)
   if (mounts.code) args.push("--mount", `type=bind,source=${home}/code,target=/host/code,readonly`)