diff --git a/lake-manifest.json b/lake-manifest.json
index e1e5e90..45c1864 100644
--- a/lake-manifest.json
+++ b/lake-manifest.json
@@ -5,20 +5,20 @@
    "type": "git",
    "subDir": null,
    "scope": "",
-   "rev": "7152850e7b216a0d409701617721b6e469d34bf6",
+   "rev": "b5b9e2bb45ce91e4bc44eaa738c3a8910404ab82",
    "name": "aesop",
    "manifestFile": "lake-manifest.json",
-   "inputRev": "7152850e7b216a0d409701617721b6e469d34bf6",
+   "inputRev": "master",
    "inherited": false,
    "configFile": "lakefile.toml"},
   {"url": "https://github.com/leanprover-community/batteries.git",
    "type": "git",
    "subDir": null,
    "scope": "",
-   "rev": "32dc18cde3684679f3c003de608743b57498c56f",
+   "rev": "e535e4feb0aa360e59e7adf4837b91ffbfb8c943",
    "name": "batteries",
    "manifestFile": "lake-manifest.json",
-   "inputRev": "32dc18cde3684679f3c003de608743b57498c56f",
+   "inputRev": "main",
    "inherited": false,
    "configFile": "lakefile.toml"}],
  "name": "LeanCopilot",
diff --git a/lakefile.lean b/lakefile.lean
index ecd94fe..51c15df 100644
--- a/lakefile.lean
+++ b/lakefile.lean
@@ -28,9 +28,14 @@ deriving Inhabited, BEq
 
 
 def nproc : IO Nat := do
-  let cmd := if getOS! == .windows then "cmd" else "nproc"
-  let args := if getOS! == .windows then #["/c echo %NUMBER_OF_PROCESSORS%"] else #[]
+  let (cmd, args) :=
+    match getOS! with
+    | .windows => ("cmd", #["/c echo %NUMBER_OF_PROCESSORS%"])
+    | .macos => ("sysctl", #["-n", "hw.ncpu"])
+    | .linux => ("nproc", #[])
   let out ← IO.Process.output {cmd := cmd, args := args, stdin := .null}
+  if out.exitCode != 0 then
+    return 4
   return out.stdout.trimAscii.toNat!
 
 
@@ -422,8 +427,8 @@ extern_lib libleanffi pkg := do
   buildStaticLib (pkg.sharedLibDir / name) #[ct2O]
 
 
-require batteries from git "https://github.com/leanprover-community/batteries.git" @ "32dc18cde3684679f3c003de608743b57498c56f"
-require aesop from git "https://github.com/leanprover-community/aesop" @ "7152850e7b216a0d409701617721b6e469d34bf6"
+require batteries from git "https://github.com/leanprover-community/batteries.git" @ "main"
+require aesop from git "https://github.com/leanprover-community/aesop" @ "master"
 
 meta if get_config? env = some "dev" then -- dev is so not everyone has to build it
 require «doc-gen4» from git "https://github.com/leanprover/doc-gen4" @ "main"
diff --git a/lean-toolchain b/lean-toolchain
index 5a8f161..63f51ea 100644
--- a/lean-toolchain
+++ b/lean-toolchain
@@ -1 +1 @@
-leanprover/lean4:v4.30.0
\ No newline at end of file
+leanprover/lean4:v4.32.0-rc1
\ No newline at end of file