diff --git a/lib/ccweb-mcp-server.js b/lib/ccweb-mcp-server.js
index 4ebf81e..654b183 100644
--- a/lib/ccweb-mcp-server.js
+++ b/lib/ccweb-mcp-server.js
@@ -38,15 +38,10 @@ const TOOLS = [
   },
   {
     name: 'ccweb_create_conversation',
-    description: '创建一个新的 ccweb 持久对话。只用于需要在会话列表中长期追踪、后续可继续对话的工作流；一次性并行研究应优先使用子代能力。',
+    description: '创建一个新的 ccweb 持久对话。Agent 固定继承来源对话，不作为参数指定；只用于需要在会话列表中长期追踪、后续可继续对话的工作流；一次性并行研究应优先使用子代能力。',
     inputSchema: {
       type: 'object',
       properties: {
-        agent: {
-          type: 'string',
-          enum: ['claude', 'codex', 'codexapp'],
-          description: '可选。新对话使用的 Agent，默认继承来源对话。',
-        },
         cwd: {
           type: 'string',
           description: '可选。新对话工作目录；指定时必须是已存在的绝对路径，默认继承来源对话 cwd。',
diff --git a/scripts/regression.js b/scripts/regression.js
index f0d98ac..cfc2b46 100644
--- a/scripts/regression.js
+++ b/scripts/regression.js
@@ -726,12 +726,13 @@ async function main() {
       sourceSessionId: codexSession.sessionId,
       sourceHopCount: 0,
       args: {
-        agent: 'codex',
+        agent: 'claude',
         title: 'MCP Created Conversation',
         initialMessage: 'mcp created initial prompt',
       },
     });
     assert(mcpCreate.status === 200 && mcpCreate.body?.ok, `MCP create conversation should succeed: ${JSON.stringify(mcpCreate.body)}`);
+    assert(mcpCreate.body.agent === 'codex', 'MCP create conversation should ignore agent args and inherit the source agent');
     assert(mcpCreate.body.cwd === codexInitCwd, 'MCP create conversation should inherit source cwd by default');
     assert(mcpCreate.body.mode === 'plan', 'MCP create conversation should inherit source mode by default');
     assert(mcpCreate.body.status === 'running', 'MCP create with initialMessage should start the new conversation');
@@ -739,6 +740,7 @@ async function main() {
     await nextMessage(messages, ws, (msg) => msg.type === 'background_done' && msg.sessionId === mcpCreate.body.conversationId);
     const storedMcpCreated = JSON.parse(fs.readFileSync(path.join(sessionsDir, `${mcpCreate.body.conversationId}.json`), 'utf8'));
     assert(storedMcpCreated.title === 'MCP Created Conversation', 'MCP created conversation should persist the requested title');
+    assert(storedMcpCreated.agent === 'codex', 'MCP created conversation should persist the inherited source agent');
     assert(storedMcpCreated.createdFrom?.sourceSessionId === codexSession.sessionId, 'MCP created conversation should persist source metadata');
     assert(storedMcpCreated.messages.some((message) => message.content === 'mcp created initial prompt' && message.crossConversation?.sourceSessionId === codexSession.sessionId), 'MCP created conversation should persist the initial cross-conversation message');
     assert(storedMcpCreated.messages.some((message) => message.role === 'assistant' && /mcp created initial prompt/.test(String(message.content || ''))), 'MCP created conversation should run the initial prompt');
@@ -750,7 +752,7 @@ async function main() {
       sourceSessionId: codexSession.sessionId,
       sourceHopCount: 0,
       args: {
-        agent: 'codex',
+        agent: 'claude',
         cwd: mcpReplyCreateCwd,
         title: 'MCP Reply Conversation',
         initialMessage: 'mcp create request reply',
@@ -758,6 +760,7 @@ async function main() {
       },
     });
     assert(mcpCreateReply.status === 200 && mcpCreateReply.body?.ok, `MCP create conversation with requestReply should succeed: ${JSON.stringify(mcpCreateReply.body)}`);
+    assert(mcpCreateReply.body.agent === 'codex', 'MCP create requestReply should inherit source agent even if args.agent is passed');
     assert(mcpCreateReply.body.cwd === mcpReplyCreateCwd, 'MCP create conversation should use an explicit absolute cwd');
     assert(mcpCreateReply.body.requestId && mcpCreateReply.body.replyStatus === 'waiting', 'MCP create requestReply should return a waiting request id');
     await nextMessage(messages, ws, (msg) => msg.type === 'background_done' && msg.sessionId === mcpCreateReply.body.conversationId);
diff --git a/server.js b/server.js
index 63517af..b58747c 100644
--- a/server.js
+++ b/server.js
@@ -3251,7 +3251,9 @@ function createMcpConversation(args = {}, sourceSessionId = '', sourceHopCount =
   }
 
   const now = new Date().toISOString();
-  const created = createPersistentConversationSession(args, {
+  const createArgs = { ...args };
+  delete createArgs.agent;
+  const created = createPersistentConversationSession(createArgs, {
     sourceSession,
     strict: true,
     requireAbsoluteCwd: true,
@@ -6324,15 +6326,10 @@ function codexAppCommunicationDynamicTools() {
     {
       name: 'ccweb_create_conversation',
       namespace: 'ccweb',
-      description: '创建新的 cc-web 持久对话。只用于需要长期追踪、后续继续对话或跨项目工作区管理的场景；一次性并行研究应使用子代能力。',
+      description: '创建新的 cc-web 持久对话。Agent 固定继承来源对话，不作为参数指定；只用于需要长期追踪、后续继续对话或跨项目工作区管理的场景；一次性并行研究应使用子代能力。',
       inputSchema: {
         type: 'object',
         properties: {
-          agent: {
-            type: 'string',
-            enum: ['claude', 'codex', 'codexapp'],
-            description: '可选。新对话 Agent，默认继承来源对话。',
-          },
           cwd: {
             type: 'string',
             description: '可选。新对话工作目录；指定时必须是已存在的绝对路径，默认继承来源对话 cwd。',