diff --git a/packages/coding-agent/CHANGELOG.md b/packages/coding-agent/CHANGELOG.md
index 814067a56..a5221a0d6 100644
--- a/packages/coding-agent/CHANGELOG.md
+++ b/packages/coding-agent/CHANGELOG.md
@@ -16,6 +16,7 @@
 - Fixed resumed sessions corrupting the next appended entry when their JSONL file lacks a trailing newline ([#8345](https://github.com/earendil-works/pi/issues/8345)).
 - Fixed extension messages sent with `triggerTurn: false` while the agent is running being inserted between a tool call and its result, which made providers that validate message order reject the replayed history. They are now appended once the turn's tool results are in ([#8537](https://github.com/earendil-works/pi/issues/8537)).
 - Fixed compaction and branch summaries forcing `toolChoice: "none"` ([#8649](https://github.com/earendil-works/pi/issues/8649), [#8638](https://github.com/earendil-works/pi/issues/8638)).
+- Fixed Google Vertex requests failing with `HttpsProxyAgent is not a constructor` when the bundled Node.js runtime uses an HTTP(S) proxy ([#8610](https://github.com/earendil-works/pi/issues/8610)).
 
 ## [0.84.3] - 2026-08-24
 
diff --git a/scripts/build-coding-agent-bundle.mjs b/scripts/build-coding-agent-bundle.mjs
index 1b6d233eb..c27e8d56d 100644
--- a/scripts/build-coding-agent-bundle.mjs
+++ b/scripts/build-coding-agent-bundle.mjs
@@ -49,6 +49,30 @@ export function createJiti(...args) {
 	},
 };
 
+const httpsProxyAgentNamedExportPlugin = {
+	name: "https-proxy-agent-named-export",
+	setup(build) {
+		build.onResolve({ filter: /^https-proxy-agent$/ }, (args) => {
+			if (args.kind !== "dynamic-import") return undefined;
+			return {
+				namespace: "https-proxy-agent-named-export",
+				path: args.path,
+			};
+		});
+		build.onLoad(
+			{
+				filter: /^https-proxy-agent$/,
+				namespace: "https-proxy-agent-named-export",
+			},
+			() => ({
+				contents: 'export { HttpsProxyAgent } from "https-proxy-agent";',
+				loader: "js",
+				resolveDir: repoRoot,
+			}),
+		);
+	},
+};
+
 function commonBuildOptions() {
 	return {
 		absWorkingDir: repoRoot,
@@ -67,7 +91,7 @@ function commonBuildOptions() {
 		// package replaces it with a synchronous lazy require so jiti loads only
 		// when importing an extension; Babel remains deferred until a cache miss
 		// needs transformation.
-		plugins: [lazyJitiPlugin],
+		plugins: [lazyJitiPlugin, httpsProxyAgentNamedExportPlugin],
 		sourcemap: false,
 		target: "node22.19",
 		// Do not apply the monorepo's source-oriented path aliases while bundling