diff --git a/packages/cli/src/runtime-install.spec.ts b/packages/cli/src/runtime-install.spec.ts
index 883f1116..df0ee9fb 100644
--- a/packages/cli/src/runtime-install.spec.ts
+++ b/packages/cli/src/runtime-install.spec.ts
@@ -25,6 +25,18 @@ const ephemeral: RuntimePaths = {
   serviceTemplate: join(npxCli, 'packaging/systemd/codor.service'),
 };
 
+const dlxCli = join(
+  HOME,
+  '.local/share/pnpm/pnpm-cache/dlx/abcd1234ef567890/1706000000000/node_modules/@richhardry/codor/node_modules/@codor/cli',
+);
+const dlxEphemeral: RuntimePaths = {
+  root: dlxCli,
+  layout: 'installed-package',
+  cliEntrypoint: join(dlxCli, 'dist/index.js'),
+  staticRoot: join(dlxCli, 'runtime/web'),
+  serviceTemplate: join(dlxCli, 'packaging/systemd/codor.service'),
+};
+
 const checkoutRoot = join(HOME, 'git/codor');
 const checkout: RuntimePaths = {
   root: checkoutRoot,
@@ -95,8 +107,9 @@ function fakeIo(options: { existing?: string; failCopy?: boolean; incompleteCopy
 
 // harn:assume setup-installs-durable-per-user-runtime-atomically ref=durable-runtime-install-regression
 describe('isEphemeralRuntime', () => {
-  it('flags npx cache and temp paths, not stable locations', () => {
+  it('flags npx cache, pnpm dlx cache, and temp paths, not stable locations', () => {
     expect(isEphemeralRuntime(join(HOME, '.npm/_npx/abcd1234'))).toBe(true);
+    expect(isEphemeralRuntime(join(HOME, '.local/share/pnpm/pnpm-cache/dlx/abcd1234ef567890/1706000000000'))).toBe(true);
     expect(isEphemeralRuntime(join(tmpdir(), 'x'))).toBe(true);
     expect(isEphemeralRuntime('/opt/codor')).toBe(false);
     expect(isEphemeralRuntime(checkoutRoot)).toBe(false);
@@ -117,6 +130,17 @@ describe('installDurableRuntime', () => {
     expect(result.runtime.cliEntrypoint).not.toContain('_npx');
   });
 
+  it('stages, validates, and swaps an ephemeral pnpm dlx runtime into ~/.codor/runtime', () => {
+    const { io, moves } = fakeIo();
+    const result = installDurableRuntime({ runtime: dlxEphemeral, dataDir: DATA, version: '0.10.0', io });
+    expect(result.action).toBe('installed');
+    expect(result.location).toBe(LOCATION);
+    expect(moves).toContainEqual([`${LOCATION}.staging`, LOCATION]);
+    // Rooted at the durable location, not the dlx cache the source runtime lived in.
+    expect(result.runtime.cliEntrypoint).toContain(LOCATION);
+    expect(result.runtime.cliEntrypoint).not.toContain('dlx');
+  });
+
   it('uses a source checkout in place without copying', () => {
     const { io, copies } = fakeIo();
     const result = installDurableRuntime({ runtime: checkout, dataDir: DATA, version: '0.10.0', io });
diff --git a/packages/cli/src/runtime-install.ts b/packages/cli/src/runtime-install.ts
index 7fe57cda..43993fb5 100644
--- a/packages/cli/src/runtime-install.ts
+++ b/packages/cli/src/runtime-install.ts
@@ -52,10 +52,15 @@ export function durableRuntimeLocation(dataDir: string): string {
   return join(dataDir, 'runtime');
 }
 
-/** A path is ephemeral when it lives in an npx cache or the OS temp directory. */
+/** A path is ephemeral when it lives in an npx cache, a pnpm dlx cache, or the OS temp directory. */
 export function isEphemeralRuntime(path: string): boolean {
   const temp = tmpdir();
-  return path.includes(`${sep}_npx${sep}`) || path === temp || path.startsWith(temp + sep);
+  return (
+    path.includes(`${sep}_npx${sep}`) ||
+    path.includes(`${sep}dlx${sep}`) ||
+    path === temp ||
+    path.startsWith(temp + sep)
+  );
 }
 
 function installedWrapperPackageJson(location: string): string {
@@ -65,7 +70,8 @@ function installedWrapperPackageJson(location: string): string {
 // harn:assume setup-installs-durable-per-user-runtime-atomically ref=durable-runtime-install
 /** The self-contained module tree the running CLI resolves against, and whether
  *  it is already durable (a source checkout or a stable install) or ephemeral
- *  (an npx cache / temp dir that must be copied before a service points at it). */
+ *  (an npx cache, a pnpm dlx cache, or a temp dir that must be copied before a
+ *  service points at it). */
 export function resolveInstallSource(runtime: RuntimePaths): { installRoot: string; nodeModules: string; durable: boolean } {
   if (runtime.layout === 'source-checkout') {
     return { installRoot: runtime.root, nodeModules: join(runtime.root, 'node_modules'), durable: true };