diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 77824e1..db3155b 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -17,7 +17,6 @@ jobs:
           key: ${{ runner.os }}-gradle-${{ hashFiles('**/*.gradle') }}
           restore-keys: |
             ${{ runner.os }}-gradle-
-      - run: |
-          ./gradlew spotlessCheck build
-      - run: |
-          ./gradlew jspecifySamplesTest -x ensureCheckerFrameworkBuilt
+      - run: ./initialize-project
+      - run: ./gradlew spotlessCheck build
+      - run: ./gradlew jspecifySamplesTest -x ensureCheckerFrameworkBuilt
diff --git a/README.md b/README.md
index 2bf5938..7517e51 100644
--- a/README.md
+++ b/README.md
@@ -29,14 +29,15 @@ looking to try it out, here are some instructions, *which might fail*
 and need to be worked around as described later in this section:
 
 ```
-# Build the checker:
+# Download the checker, its fork of Checker Framework, and the unreleased JSpecify code and samples:
 
 $ git clone https://github.com/jspecify/nullness-checker-for-checker-framework
-
 $ cd nullness-checker-for-checker-framework
+$ ./initialize-project
 
-$ ./gradlew assemble
+# Build it:
 
+$ ./gradlew assemble
 
 # Use it:
 
diff --git a/build.gradle b/build.gradle
index c8c85db..f6ec2e3 100644
--- a/build.gradle
+++ b/build.gradle
@@ -18,7 +18,6 @@ ext {
     parentDir = file("${rootDir}/../").absolutePath
     cfHome = "${parentDir}/checker-framework"
     jspecifyHome = "${parentDir}/jspecify"
-    plumeScripts = "${rootDir}/.plume-scripts"
 }
 
 sourceCompatibility = 1.9
@@ -101,64 +100,26 @@ spotless {
 }
 
 task ensureCheckerFrameworkBuilt() {
-    description 'Clone or update the Checker Framework and then build it and all dependencies'
+    description 'Build the Checker Framework and all dependencies'
     doLast {
-        if (!file(plumeScripts).exists()) {
+        /* Introduce an autoUpdateCF variable if we want to support that usage.
+        if (autoUpdateCF) {
             exec {
-                workingDir "${rootDir}"
+                workingDir cfHome
                 executable 'git'
-                args = ['clone', '-q', '--depth', '1', 'https://github.com/plume-lib/plume-scripts.git', plumeScripts]
+                args = ['pull', '-q']
+                ignoreExitValue = true
             }
-        }
-        def jspecifyExisted = file(jspecifyHome).exists()
-
-        if (file(cfHome).exists()) {
-            /* Introduce an autoUpdateCF variable if we want to support that usage.
-            if (autoUpdateCF) {
-                exec {
-                    workingDir cfHome
-                    executable 'git'
-                    args = ['pull', '-q']
-                    ignoreExitValue = true
-                }
-            } else {
-                println "Found existing ${cfHome}. Use -PautoUpdateCF=true if you want to git pull automatically."
-            }
-            */
         } else {
-            exec {
-                workingDir rootDir
-                executable "${plumeScripts}/git-clone-related"
-                args = ['jspecify', 'checker-framework', '-q']
-            }
+            println "Found existing ${cfHome}. Use -PautoUpdateCF=true if you want to git pull automatically."
         }
+        */
         exec {
             workingDir cfHome
             executable './gradlew'
             // Skip Javadoc to save time. Perform a release build so that we repackage javaparser (not that that seems to matter here, but it's consistent with how the Checker Framework would be deployed).
             args = ['cloneAndBuildDependencies', '-x', 'javadoc', '-x', 'allJavadoc', '-Prelease=true']
         }
-
-        // We test using some modified samples in a different branch of the jspecify repo, so we want to change to that branch.
-        // However, if there was a JSpecify client to begin with, don't mess with it, as the developer may be running tests in a different branch.
-        if (!jspecifyExisted) {
-            // The CF build process uses --single-branch when it clones the jspecify repo, so the resulting clone doesn't have the branch we want.
-            exec {
-                workingDir jspecifyHome
-                executable 'git'
-                args = ['config', 'remote.origin.fetch', '+refs/heads/*:refs/remotes/origin/*']
-            }
-            exec {
-                workingDir jspecifyHome
-                executable 'git'
-                args = ['fetch']
-            }
-            exec {
-                workingDir jspecifyHome
-                executable 'git'
-                args = ['checkout', '-q', 'samples-google-prototype']
-            }
-        }
     }
 }
 
diff --git a/initialize-project b/initialize-project
new file mode 100755
index 0000000..c5e6be9
--- /dev/null
+++ b/initialize-project
@@ -0,0 +1,22 @@
+#!/bin/bash
+
+set -eu
+
+readonly PLUME_SCRIPTS=.plume-scripts
+readonly CHECKER_FRAMEWORK=../checker-framework
+readonly JSPECIFY=../jspecify
+
+if [[ ! -d "${PLUME_SCRIPTS}" ]]; then
+  git clone -q --depth 1 https://github.com/plume-lib/plume-scripts.git \
+    "${PLUME_SCRIPTS}"
+fi
+
+if [[ ! -d "${CHECKER_FRAMEWORK}" ]]; then
+  "${PLUME_SCRIPTS}"/git-clone-related jspecify checker-framework -q
+fi
+
+if [[ ! -d "${JSPECIFY}" ]]; then
+  # We test using some modified samples in a different branch of the jspecify
+  # repo, so we check out that branch.
+  "${PLUME_SCRIPTS}"/git-clone-related --upstream-branch samples-google-prototype jspecify jspecify -q
+fi