diff --git a/plugins/aios-tenant-boundary/session-broker-client.js b/plugins/aios-tenant-boundary/session-broker-client.js
new file mode 100644
index 0000000..d3967aa
--- /dev/null
+++ b/plugins/aios-tenant-boundary/session-broker-client.js
@@ -0,0 +1,76 @@
+import fs from "node:fs";
+import path from "node:path";
+
+const ALLOWED_BROKER_HOSTS = new Set(["127.0.0.1", "localhost"]);
+const DEFAULT_TIMEOUT_MS = 3000;
+
+export function brokerCredentialFromPath(credentialPath) {
+  if (!path.isAbsolute(credentialPath)) throw new Error("broker_credential_path_invalid");
+  const stat = fs.lstatSync(credentialPath);
+  if (!stat.isFile() || stat.isSymbolicLink()) throw new Error("broker_credential_path_invalid");
+  if (process.platform !== "win32" && (stat.mode & 0o077) !== 0) {
+    throw new Error("broker_credential_permissions_invalid");
+  }
+  const token = fs.readFileSync(credentialPath, "utf8").trim();
+  if (!token) throw new Error("broker_credential_empty");
+  return token;
+}
+
+export function assertLocalBrokerEndpoint(endpoint) {
+  const safe = new URL(endpoint);
+  if (safe.protocol !== "http:") throw new Error("broker_endpoint_protocol_invalid");
+  if (!ALLOWED_BROKER_HOSTS.has(safe.hostname)) throw new Error("broker_endpoint_host_invalid");
+  if (safe.username || safe.password || safe.search || safe.hash) throw new Error("broker_endpoint_invalid");
+  if (safe.pathname === "/") safe.pathname = "/v1/sessions/provision";
+  return safe;
+}
+
+export async function callBrokerProvision({
+  endpoint,
+  credentialPath,
+  payload,
+  timeoutMs = DEFAULT_TIMEOUT_MS,
+}) {
+  const brokerUrl = assertLocalBrokerEndpoint(endpoint);
+  const credential = brokerCredentialFromPath(credentialPath);
+  const controller = new AbortController();
+  const timer = setTimeout(() => controller.abort(), Math.min(Math.max(Number(timeoutMs) || DEFAULT_TIMEOUT_MS, 500), 15_000));
+  try {
+    const response = await fetch(brokerUrl, {
+      method: "POST",
+      signal: controller.signal,
+      headers: {
+        "Content-Type": "application/json",
+        "Authorization": `Bearer ${credential}`,
+      },
+      body: JSON.stringify(payload),
+    });
+    const responseBody = await response.text();
+    let body;
+    try {
+      body = responseBody ? JSON.parse(responseBody) : {};
+    } catch {
+      throw new Error("broker_response_not_json");
+    }
+    if (!response.ok) {
+      const reason = typeof body?.error === "string" ? body.error : `http_${response.status}`;
+      const error = new Error(reason);
+      error.code = "broker_http_error";
+      error.status = response.status;
+      throw error;
+    }
+    return body;
+  } catch (error) {
+    if (error.name === "AbortError") {
+      const timeout = new Error("broker_timeout");
+      timeout.code = "broker_timeout";
+      throw timeout;
+    }
+    if (error.code) throw error;
+    const transport = new Error("broker_unreachable");
+    transport.code = "broker_unreachable";
+    throw transport;
+  } finally {
+    clearTimeout(timer);
+  }
+}