diff --git a/doc/flake.nix b/doc/flake.nix
index b72a6fa37930..cf8444d7ed24 100644
--- a/doc/flake.nix
+++ b/doc/flake.nix
@@ -4,15 +4,15 @@
   inputs.lean.url = path:../.;
   inputs.flake-utils.follows = "lean/flake-utils";
   inputs.mdBook = {
-    url = github:leanprover/mdBook;
+    url = "github:leanprover/mdBook";
     flake = false;
   };
   inputs.alectryon = {
-    url = github:Kha/alectryon/typeid;
+    url = "github:Kha/alectryon/typeid";
     flake = false;
   };
   inputs.leanInk = {
-    url = github:leanprover/LeanInk;
+    url = "github:leanprover/LeanInk";
     flake = false;
   };
 
diff --git a/flake.nix b/flake.nix
index 43520533dd11..1ccf6fcad4a5 100644
--- a/flake.nix
+++ b/flake.nix
@@ -1,11 +1,11 @@
 {
   description = "Lean interactive theorem prover";
 
-  inputs.nixpkgs.url = github:NixOS/nixpkgs/nixpkgs-unstable;
-  inputs.flake-utils.url = github:numtide/flake-utils;
-  inputs.nix.url = github:NixOS/nix;
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+  inputs.flake-utils.url = "github:numtide/flake-utils";
+  inputs.nix.url = "github:NixOS/nix";
   inputs.lean4-mode = {
-    url = github:leanprover/lean4-mode;
+    url = "github:leanprover/lean4-mode";
     flake = false;
   };
   # used *only* by `stage0-from-input` below
diff --git a/nix/templates/pkg/flake.nix b/nix/templates/pkg/flake.nix
index 4ecd6e3d8bf9..42bf6f46b1d0 100644
--- a/nix/templates/pkg/flake.nix
+++ b/nix/templates/pkg/flake.nix
@@ -1,8 +1,8 @@
 {
   description = "My Lean package";
 
-  inputs.lean.url = github:leanprover/lean4;
-  inputs.flake-utils.url = github:numtide/flake-utils;
+  inputs.lean.url = "github:leanprover/lean4";
+  inputs.flake-utils.url = "github:numtide/flake-utils";
 
   outputs = { self, lean, flake-utils }: flake-utils.lib.eachDefaultSystem (system:
     let
diff --git a/tests/bench/flake.nix b/tests/bench/flake.nix
index 4bda95a7f233..db0e7b4e7de9 100644
--- a/tests/bench/flake.nix
+++ b/tests/bench/flake.nix
@@ -1,10 +1,10 @@
 {
   inputs.lean.url = "git+file:../..";
-  inputs.flake-utils.url = github:numtide/flake-utils;
+  inputs.flake-utils.url = "github:numtide/flake-utils";
   inputs.flake-utils.follows = "lean/flake-utils";
-  inputs.temci.url = github:Kha/temci;
-  inputs.nixpkgs.url = github:NixOS/nixpkgs/nixpkgs-unstable;
-  inputs.disable-st.url = https://github.com/Kha/lean4/commit/no-st.patch;
+  inputs.temci.url = "github:Kha/temci";
+  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+  inputs.disable-st.url = "https://github.com/Kha/lean4/commit/no-st.patch";
   inputs.disable-st.flake = false;
 
   outputs = inputs: inputs.flake-utils.lib.eachDefaultSystem (system: { packages = rec {