diff --git a/packages/safe-chain/src/registryProxy/certUtils.js b/packages/safe-chain/src/registryProxy/certUtils.js
index abe4d05..f94bda9 100644
--- a/packages/safe-chain/src/registryProxy/certUtils.js
+++ b/packages/safe-chain/src/registryProxy/certUtils.js
@@ -12,17 +12,6 @@ export function getCaCertPath() {
   return path.join(certFolder, "ca-cert.pem");
 }
 
-/**
- * @param {forge.pki.PublicKey} publicKey
- * @returns {string}
- */
-function createKeyIdentifier(publicKey) {
-  return forge.pki.getPublicKeyFingerprint(publicKey, {
-    encoding: "binary",
-    md: forge.md.sha1.create(),
-  });
-}
-
 /**
  * @param {string} hostname
  * @returns {{privateKey: string, certificate: string}}
@@ -62,19 +51,39 @@ export function generateCertForHost(hostname) {
     },
     {
       /*
-        extKeyUsage serverAuth is required for TLS server authentication.
-        This is especially important for Python venv environments, which use their own
-        certificate validation logic and will reject certificates lacking the serverAuth EKU.
-        Adding serverAuth does not impact other usages
+        Extended Key Usage (EKU) serverAuth extension
+
+        Needed for TLS server authentication. This extension indicates the certificate's
+        public key may be used for TLS WWW server authentication.
+        Python virtualenv environments (like pipx-installed Poetry) enforce this strictly
+        https://www.rfc-editor.org/rfc/rfc5280#section-4.2.1.12
       */
       name: "extKeyUsage",
       serverAuth: true,
     },
     {
+      /*
+        Subject Key Identifier (SKI)
+        
+        Needed for Python virtualenv SSL validation and certificate chain building.
+        This extension provides a means of identifying certificates containing a particular public key.
+        Python virtualenv environments require this for proper certificate chain validation.
+        System Python installations may be more lenient.
+        https://www.rfc-editor.org/rfc/rfc5280#section-4.2.1.2
+      */
       name: "subjectKeyIdentifier",
       subjectKeyIdentifier: createKeyIdentifier(cert.publicKey),
     },
     {
+      /*
+        Authority Key Identifier (AKI)
+        
+        Needed for Python virtualenv SSL validation and certificate path validation.
+        This extension identifies the public key corresponding to the private key used to sign
+        this certificate. It links this certificate to its issuing CA certificate.
+        Without this, Python virtualenv certificate validation might fail
+        https://www.rfc-editor.org/rfc/rfc5280#section-4.2.1.1
+      */
       name: "authorityKeyIdentifier",
       keyIdentifier: authorityKeyIdentifier,
     },
@@ -142,7 +151,7 @@ function generateCa() {
 
   const attrs = [{ name: "commonName", value: "safe-chain proxy" }];
   cert.setSubject(attrs);
-  cert.setIssuer(attrs);
+  cert.setIssuer(attrs); // Self-signed: issuer === subject
   const keyIdentifier = createKeyIdentifier(cert.publicKey);
   cert.setExtensions([
     {
@@ -156,10 +165,28 @@ function generateCa() {
       digitalSignature: true,
       keyEncipherment: true,
     },
+      /*
+        Subject Key Identifier (SKI)
+        
+        Needed for Python virtualenv SSL validation and certificate chain building.
+        This extension provides a means of identifying certificates containing a particular public key.
+        Python virtualenv environments require this for proper certificate chain validation.
+        System Python installations may be more lenient.
+        https://www.rfc-editor.org/rfc/rfc5280#section-4.2.1.2
+      */
     {
       name: "subjectKeyIdentifier",
       subjectKeyIdentifier: keyIdentifier,
     },
+      /*
+        Authority Key Identifier (AKI)
+        
+        Needed for Python virtualenv SSL validation and certificate path validation.
+        This extension identifies the public key corresponding to the private key used to sign
+        this certificate. It links this certificate to its issuing CA certificate.
+        Without this, Python virtualenv certificate validation might fail
+        https://www.rfc-editor.org/rfc/rfc5280#section-4.2.1.1
+      */
     {
       name: "authorityKeyIdentifier",
       keyIdentifier,
@@ -172,3 +199,14 @@ function generateCa() {
     certificate: cert,
   };
 }
+
+/**
+ * @param {forge.pki.PublicKey} publicKey
+ * @returns {string}
+ */
+function createKeyIdentifier(publicKey) {
+  return forge.pki.getPublicKeyFingerprint(publicKey, {
+    encoding: "binary",
+    md: forge.md.sha1.create(),
+  });
+}
diff --git a/test/e2e/pip-ci.e2e.spec.js b/test/e2e/pip-ci.e2e.spec.js
index 63bfd90..a99b8d0 100644
--- a/test/e2e/pip-ci.e2e.spec.js
+++ b/test/e2e/pip-ci.e2e.spec.js
@@ -12,6 +12,10 @@ describe("E2E: safe-chain setup-ci command for pip/pip3", () => {
   beforeEach(async () => {
     container = new DockerTestContainer();
     await container.start();
+    
+    // Clear pip cache before each test to ensure fresh downloads through proxy
+    const shell = await container.openShell("zsh");
+    await shell.runCommand("pip3 cache purge");
   });
 
   afterEach(async () => {
diff --git a/test/e2e/pip.e2e.spec.js b/test/e2e/pip.e2e.spec.js
index 9a1adec..5d39d8c 100644
--- a/test/e2e/pip.e2e.spec.js
+++ b/test/e2e/pip.e2e.spec.js
@@ -16,6 +16,9 @@ describe("E2E: pip coverage", () => {
 
     const installationShell = await container.openShell("zsh");
     await installationShell.runCommand("safe-chain setup --include-python");
+    
+    // Clear pip cache before each test to ensure fresh downloads through proxy
+    await installationShell.runCommand("pip3 cache purge");
   });
 
   afterEach(async () => {
@@ -118,9 +121,6 @@ describe("E2E: pip coverage", () => {
 
   it(`safe-chain blocks installation of malicious Python packages`, async () => {
     const shell = await container.openShell("zsh");
-    // Clear pip cache to ensure network download through proxy
-    await shell.runCommand("pip3 cache purge");
-
     const result = await shell.runCommand(
       "pip3 install --break-system-packages safe-chain-pi-test"
     );
@@ -247,9 +247,6 @@ describe("E2E: pip coverage", () => {
 
   it(`pip3 successfully validates certificates for HTTPS downloads`, async () => {
     const shell = await container.openShell("zsh");
-    // Clear cache to force network download through proxy
-    await shell.runCommand("pip3 cache purge");
-
     const result = await shell.runCommand(
       "pip3 install --break-system-packages certifi"
     );