diff --git a/apps/server/src/provider/jsoncParserPack.test.ts b/apps/server/src/provider/jsoncParserPack.test.ts
new file mode 100644
index 000000000000..ea3f5cfa22f3
--- /dev/null
+++ b/apps/server/src/provider/jsoncParserPack.test.ts
@@ -0,0 +1,77 @@
+// @effect-diagnostics nodeBuiltinImport:off - The packaging regression must execute the emitted module from a disposable filesystem fixture.
+import { assert, it } from "@effect/vitest";
+import { build } from "vite-plus/pack";
+import * as NodeChildProcess from "node:child_process";
+import * as NodeFSP from "node:fs/promises";
+import * as NodeOS from "node:os";
+import * as NodePath from "node:path";
+import * as NodeURL from "node:url";
+
+import { jsoncParserPackInputOptions } from "../../vite.config.ts";
+
+it("starts a bundled JSONC parser and preserves comment/trailing-comma parsing", async () => {
+  const workDir = await NodeFSP.mkdtemp(NodePath.join(NodeOS.tmpdir(), "t3-jsonc-pack-"));
+  const entry = NodePath.join(workDir, "entry.mjs");
+  const outDir = NodePath.join(workDir, "out");
+
+  try {
+    await NodeFSP.writeFile(
+      entry,
+      `import { parse as parseJsonc } from "jsonc-parser";
+const errors = [];
+const parsed = parseJsonc('{ /* comment */ "provider": "codex", "args": ["--flag",], }', errors, { allowTrailingComma: true });
+if (errors.length !== 0 || parsed.provider !== "codex" || parsed.args[0] !== "--flag") {
+  throw new Error(JSON.stringify({ errors, parsed }));
+}
+const malformedErrors = [];
+parseJsonc('{ "provider": }', malformedErrors);
+if (malformedErrors.length === 0) throw new Error("Malformed JSONC was accepted");
+export const jsoncBundleProbe = {
+  provider: parsed.provider,
+  argument: parsed.args[0],
+  malformedErrorCount: malformedErrors.length,
+  moduleUrl: import.meta.url,
+};
+console.log("JSONC_BUNDLE_OK", parsed.provider, parsed.args[0], malformedErrors.length);
+`,
+    );
+
+    const result = await build({
+      cwd: process.cwd(),
+      entry,
+      outDir,
+      format: "esm",
+      deps: { alwaysBundle: ["jsonc-parser"] },
+      inputOptions: jsoncParserPackInputOptions,
+    });
+    const entryChunk = result.bundles.flatMap((bundle) => bundle.chunks)[0];
+    assert(entryChunk, "The JSONC fixture should produce an entry bundle");
+    const bundlePath = NodePath.join(outDir, entryChunk.fileName);
+    const bundleSource = await NodeFSP.readFile(bundlePath, "utf8");
+
+    assert(!bundleSource.includes('require("./impl/format")'));
+    // Run the artifact with Node itself so the packaging regression exercises
+    // the emitted module, not a transformed or mocked source import.
+    const execution = NodeChildProcess.spawnSync(process.execPath, [bundlePath], {
+      encoding: "utf8",
+      timeout: 10_000,
+    });
+    const spawnError = execution.error as NodeJS.ErrnoException | undefined;
+    if (spawnError?.code === "EPERM") {
+      // The managed test sandbox may prohibit child processes. Load the emitted
+      // .mjs directly there; CI still gets the independent Node process above.
+      const emittedModule = await import(NodeURL.pathToFileURL(bundlePath).href);
+      assert.deepEqual(emittedModule.jsoncBundleProbe, {
+        provider: "codex",
+        argument: "--flag",
+        malformedErrorCount: 1,
+        moduleUrl: NodeURL.pathToFileURL(bundlePath).href,
+      });
+    } else {
+      assert.equal(execution.status, 0, execution.stderr ?? execution.error?.message);
+      assert(execution.stdout.includes("JSONC_BUNDLE_OK codex --flag 1"));
+    }
+  } finally {
+    await NodeFSP.rm(workDir, { recursive: true, force: true });
+  }
+});
diff --git a/apps/server/vite.config.ts b/apps/server/vite.config.ts
index 14b73d2f0223..da27299b0483 100644
--- a/apps/server/vite.config.ts
+++ b/apps/server/vite.config.ts
@@ -1,5 +1,6 @@
 import "vite-plus/test/config";
 import { defineConfig, mergeConfig } from "vite-plus";
+import * as NodeModule from "node:module";
 
 import baseConfig from "../../vite.config.ts";
 import { loadRepoEnv } from "../../scripts/lib/public-config.ts";
@@ -20,6 +21,18 @@ import {
 
 export { shouldBundleCliDependency };
 
+// jsonc-parser's package `main` is its UMD build, which leaves relative
+// CommonJS requires in a single-file SEA. Point only this package at its ESM
+// entry so Rolldown bundles the parser's implementation modules.
+const nodeRequire = NodeModule.createRequire(import.meta.url);
+export const jsoncParserPackInputOptions = {
+  resolve: {
+    alias: {
+      "jsonc-parser$": nodeRequire.resolve("jsonc-parser/lib/esm/main.js"),
+    },
+  },
+};
+
 const repoEnv = loadRepoEnv();
 const cliBuildChannel = /^[^-+]+-(?:nightly|preview)\./.test(packageJson.version)
   ? "nightly"
@@ -106,6 +119,7 @@ export default mergeConfig(
         neverBundle: (id: string) => isExternalCliDependency(id),
         onlyBundle: false,
       },
+      inputOptions: jsoncParserPackInputOptions,
       banner: {
         js: "#!/usr/bin/env node\n",
       },