diff --git a/.github/workflows/devtools_regression_tests.yml b/.github/workflows/devtools_regression_tests.yml
index 4fe3d0ccb0..1fd18d1727 100644
--- a/.github/workflows/devtools_regression_tests.yml
+++ b/.github/workflows/devtools_regression_tests.yml
@@ -123,7 +123,7 @@ jobs:
       - name: Display structure of build
         run: ls -R build
       - run: ./scripts/ci/download_devtools_regression_build.js ${{ matrix.version }} --replaceBuild
-      - run: node ./scripts/jest/jest-cli.js --build --project devtools --release-channel=experimental --reactVersion ${{ matrix.version }} --ci=github
+      - run: node ./scripts/jest/jest-cli.js --build --project devtools --release-channel=experimental --reactVersion ${{ matrix.version }} --ci
 
   run_devtools_e2e_tests_for_versions:
     name: Run DevTools e2e tests for versions
diff --git a/.github/workflows/runtime_build_and_test.yml b/.github/workflows/runtime_build_and_test.yml
index 2413ed3521..7186e60f9b 100644
--- a/.github/workflows/runtime_build_and_test.yml
+++ b/.github/workflows/runtime_build_and_test.yml
@@ -141,7 +141,7 @@ jobs:
           path: "**/node_modules"
           key: ${{ runner.arch }}-${{ runner.os }}-modules-${{ hashFiles('yarn.lock') }}
       - run: yarn install --frozen-lockfile
-      - run: yarn test ${{ matrix.params }} --ci=github --shard=${{ matrix.shard }}
+      - run: yarn test ${{ matrix.params }} --ci --shard=${{ matrix.shard }}
 
   # ----- BUILD -----
   build_and_lint:
@@ -170,7 +170,7 @@ jobs:
           path: "**/node_modules"
           key: ${{ runner.arch }}-${{ runner.os }}-modules-${{ hashFiles('yarn.lock') }}
       - run: yarn install --frozen-lockfile
-      - run: yarn build --index=${{ matrix.worker_id }} --total=20 --r=${{ matrix.release_channel }} --ci=github
+      - run: yarn build --index=${{ matrix.worker_id }} --total=20 --r=${{ matrix.release_channel }} --ci
         env:
           CI: github
           RELEASE_CHANNEL: ${{ matrix.release_channel }}
@@ -248,7 +248,7 @@ jobs:
           merge-multiple: true
       - name: Display structure of build
         run: ls -R build
-      - run: yarn test --build ${{ matrix.test_params }} --shard=${{ matrix.shard }} --ci=github
+      - run: yarn test --build ${{ matrix.test_params }} --shard=${{ matrix.shard }} --ci
 
   process_artifacts_combined:
     name: Process artifacts combined
diff --git a/.github/workflows/runtime_fuzz_tests.yml b/.github/workflows/runtime_fuzz_tests.yml
index dac4dd095a..54b6d9eb3d 100644
--- a/.github/workflows/runtime_fuzz_tests.yml
+++ b/.github/workflows/runtime_fuzz_tests.yml
@@ -32,5 +32,5 @@ jobs:
       shell: bash
     - name: Run fuzz tests
       run: |-
-        FUZZ_TEST_SEED=$RANDOM yarn test fuzz --ci=github
-        FUZZ_TEST_SEED=$RANDOM yarn test --prod fuzz --ci=github
+        FUZZ_TEST_SEED=$RANDOM yarn test fuzz --ci
+        FUZZ_TEST_SEED=$RANDOM yarn test --prod fuzz --ci
diff --git a/scripts/jest/jest-cli.js b/scripts/jest/jest-cli.js
index 70d4d04b2b..b68ecaae28 100644
--- a/scripts/jest/jest-cli.js
+++ b/scripts/jest/jest-cli.js
@@ -91,8 +91,8 @@ const argv = yargs
     ci: {
       describe: 'Run tests in CI',
       requiresArg: false,
-      type: 'choices',
-      choices: ['circleci', 'github'],
+      type: 'boolean',
+      default: false,
     },
     compactConsole: {
       alias: 'c',
@@ -308,12 +308,7 @@ function getCommandArgs() {
     args.push('--useStderr');
   }
 
-  // CI Environments have limited workers.
-  if (argv.ci === 'circleci') {
-    args.push('--maxWorkers=2');
-  }
-
-  if (argv.ci === 'github') {
+  if (argv.ci === true) {
     args.push('--maxConcurrency=10');
   }
 
@@ -368,7 +363,7 @@ function main() {
   const envars = getEnvars();
   const env = Object.entries(envars).map(([k, v]) => `${k}=${v}`);
 
-  if (argv.ci !== 'github') {
+  if (argv.ci !== true) {
     // Print the full command we're actually running.
     const command = `$ ${env.join(' ')} node ${args.join(' ')}`;
     console.log(chalk.dim(command));
diff --git a/scripts/rollup/build-all-release-channels.js b/scripts/rollup/build-all-release-channels.js
index 5615b5949c..8c1ca3ced1 100644
--- a/scripts/rollup/build-all-release-channels.js
+++ b/scripts/rollup/build-all-release-channels.js
@@ -76,8 +76,8 @@ const argv = yargs.wrap(yargs.terminalWidth()).options({
   ci: {
     describe: 'Run tests in CI',
     requiresArg: false,
-    type: 'choices',
-    choices: ['circleci', 'github'],
+    type: 'boolean',
+    default: false,
   },
   type: {
     describe: `Build the given bundle type. (${Object.values(
@@ -109,7 +109,7 @@ const argv = yargs.wrap(yargs.terminalWidth()).options({
 }).argv;
 
 async function main() {
-  if (argv.ci === 'github') {
+  if (argv.ci === true) {
     buildForChannel(argv.releaseChannel, argv.total, argv.index);
     switch (argv.releaseChannel) {
       case 'stable': {
@@ -138,7 +138,7 @@ async function main() {
     // Then merge the experimental folder into the stable one. processExperimental
     // will have already removed conflicting files.
     //
-    // In CI, merging is handled automatically by CircleCI's workspace feature.
+    // In CI, merging is handled by the GitHub Download Artifacts plugin.
     mergeDirsSync(experimentalDir + '/', stableDir + '/');
 
     // Now restore the combined directory back to its original name
diff --git a/scripts/rollup/stats.js b/scripts/rollup/stats.js
index 1a33c7ed0d..d0fbce7108 100644
--- a/scripts/rollup/stats.js
+++ b/scripts/rollup/stats.js
@@ -18,7 +18,7 @@ const currentBuildResults = {
 };
 
 function saveResults() {
-  if (process.env.CI === 'github') {
+  if (process.env.CI === true) {
     mkdirp.sync('build/sizes');
     fs.writeFileSync(
       join('build', 'sizes', `bundle-sizes-${process.env.NODE_INDEX}.json`),