diff --git a/package-lock.json b/package-lock.json
index 73819222..6dfc6248 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -9,7 +9,7 @@
       "version": "0.105.0",
       "license": "Apache-2.0",
       "dependencies": {
-        "@agentclientprotocol/sdk": "2.5.0",
+        "@agentclientprotocol/sdk": "2.6.0",
         "@anthropic-ai/claude-agent-sdk": "0.3.322",
         "diff": "9.0.0",
         "zod": "4.6.7"
@@ -38,9 +38,9 @@
       }
     },
     "node_modules/@agentclientprotocol/sdk": {
-      "version": "2.5.0",
-      "resolved": "https://registry.npmjs.org/@agentclientprotocol/sdk/-/sdk-2.5.0.tgz",
-      "integrity": "sha512-MFlXeIuwN6nZSK45SAsSnVjbLgQ2r4fnthoF1lQoGJP3PdaPRpOZeCF2Dds8S4cN8yZP5QbxB1bkJccGskmcYw==",
+      "version": "2.6.0",
+      "resolved": "https://registry.npmjs.org/@agentclientprotocol/sdk/-/sdk-2.6.0.tgz",
+      "integrity": "sha512-3FtL6MkAV5F9qxg0FQV8wmBszIm2xuVPoDWOILIFSDQ+Vq3Twdh7Cw6Hk2GOPUbevgrTUpUAqZXQy7Geaj79mw==",
       "license": "Apache-2.0",
       "peerDependencies": {
         "@modelcontextprotocol/server": "^2.4.0",
diff --git a/package.json b/package.json
index 66c85b72..3b5c9acf 100644
--- a/package.json
+++ b/package.json
@@ -68,7 +68,7 @@
     "node": ">=22"
   },
   "dependencies": {
-    "@agentclientprotocol/sdk": "2.5.0",
+    "@agentclientprotocol/sdk": "2.6.0",
     "@anthropic-ai/claude-agent-sdk": "0.3.322",
     "diff": "9.0.0",
     "zod": "4.6.7"
diff --git a/src/v2/session-requests.ts b/src/v2/session-requests.ts
index de353897..2a2e90c4 100644
--- a/src/v2/session-requests.ts
+++ b/src/v2/session-requests.ts
@@ -19,8 +19,13 @@ import * as v2 from "@agentclientprotocol/sdk/experimental/v2/unstable";
 import { V2_SESSION_CAPABILITIES } from "./initialize.js";
 import { v1ContentBlock } from "./prompt.js";
 
+/**
+ * Without `configOptions`: a client sends them only to an agent that
+ * advertises `session.options`, which this one does not.
+ */
 export function v1NewSessionRequest(params: v2.NewSessionRequest): NewSessionRequest {
-  const { mcpServers, systemPrompt, ...request } = params;
+  // eslint-disable-next-line @typescript-eslint/no-unused-vars
+  const { mcpServers, systemPrompt, configOptions, ...request } = params;
   // v1 requires the list; v2 treats an omitted list as an empty one.
   return {
     ...request,