Fix middleware args (#1550)

Fixes DOC-462

Author: lnhsingh

src/oss/javascript/migrate/langchain-v1.mdx

@@ -201,7 +201,7 @@ const agent = createAgent({
   middleware: [
     summarizationMiddleware({
       model: "claude-sonnet-4-5-20250929",
-      maxTokensBeforeSummary: 1000,
+      trigger: { tokens: 1000 },
     }),
   ],
 });

src/oss/javascript/releases/langchain-v1.mdx

@@ -99,7 +99,7 @@ const agent = createAgent({
     piiRedactionMiddleware({ patterns: ["email", "phone", "ssn"] }),
     summarizationMiddleware({
       model: "claude-sonnet-4-5-20250929",
-      maxTokensBeforeSummary: 500,
+      trigger: { tokens: 500 },
     }),
     humanInTheLoopMiddleware({
       interruptOn: {

src/oss/langchain/context-engineering.mdx

@@ -1998,8 +1998,8 @@ agent = create_agent(
     middleware=[
         SummarizationMiddleware(
             model="gpt-4o-mini",
-            max_tokens_before_summary=4000,  # Trigger summarization at 4000 tokens
-            messages_to_keep=20,  # Keep last 20 messages after summary
+            trigger={"tokens": 4000},
+            keep={"messages": 20},
         ),
     ],
 )
@@ -2016,8 +2016,8 @@ const agent = createAgent({
   middleware: [
     summarizationMiddleware({
       model: "gpt-4o-mini",
-      maxTokensBeforeSummary: 4000, // Trigger summarization at 4000 tokens
-      messagesToKeep: 20, // Keep last 20 messages after summary
+      trigger: { tokens: 4000 },
+      keep: { messages: 20 },
     }),
   ],
 });

src/oss/langchain/short-term-memory.mdx

@@ -507,8 +507,8 @@ agent = create_agent(
     middleware=[
         SummarizationMiddleware(
             model="gpt-4o-mini",
-            max_tokens_before_summary=4000,  # Trigger summarization at 4000 tokens
-            messages_to_keep=20,  # Keep last 20 messages after summary
+            trigger={"tokens": 4000},
+            keep={"messages": 20},
         )
     ],
     checkpointer=checkpointer,
@@ -545,8 +545,8 @@ const agent = createAgent({
   middleware: [
     summarizationMiddleware({
       model: "gpt-4o-mini",
-      maxTokensBeforeSummary: 4000,
-      messagesToKeep: 20,
+      trigger: { tokens: 4000 },
+      keep: { messages: 20 },
     }),
   ],
   checkpointer,

src/oss/python/migrate/langchain-v1.mdx

@@ -270,7 +270,7 @@ agent = create_agent(
     middleware=[
         SummarizationMiddleware(  # [!code highlight]
             model="claude-sonnet-4-5-20250929",  # [!code highlight]
-            max_tokens_before_summary=1000  # [!code highlight]
+            trigger={"tokens": 1000}  # [!code highlight]
         )  # [!code highlight]
     ]  # [!code highlight]
 )

src/oss/python/releases/langchain-v1.mdx

@@ -101,7 +101,7 @@ agent = create_agent(
         ),
         SummarizationMiddleware(
             model="claude-sonnet-4-5-20250929",
-            max_tokens_before_summary=500
+            trigger={"tokens": 500}
         ),
         HumanInTheLoopMiddleware(
             interrupt_on={