feat: Add LangSmith integration metadata to createAgent and initChatModel (#10433)

Author: tanushree-sharma

.changeset/swift-rice-hug.md

@@ -0,0 +1,6 @@
+---
+"@langchain/core": patch
+"langchain": patch
+---
+
+feat: Add LangSmith integration metadata to createAgent and initChatModel

libs/langchain-core/src/language_models/chat_models.ts

@@ -197,6 +197,7 @@ export type LangSmithParams = {
   ls_temperature?: number;
   ls_max_tokens?: number;
   ls_stop?: Array<string>;
+  ls_integration?: string;
 };
 
 export type BindToolsInput =
@@ -321,7 +322,7 @@ export abstract class BaseChatModel<
 
       const inheritableMetadata = {
         ...runnableConfig.metadata,
-        ...this.getLsParams(callOptions),
+        ...this.getLsParamsWithDefaults(callOptions),
       };
       const invocationParams = this?.invocationParams(callOptions);
       const metadataInvocationParams =
@@ -431,6 +432,18 @@ export abstract class BaseChatModel<
     };
   }
 
+  /**
+   * Wraps getLsParams() and always appends ls_integration.
+   * This ensures the integration tag is present even when
+   * partner packages fully override getLsParams().
+   */
+  getLsParamsWithDefaults(options: this["ParsedCallOptions"]): LangSmithParams {
+    return {
+      ...this.getLsParams(options),
+      ls_integration: "langchain_chat_model",
+    };
+  }
+
   /** @ignore */
   async _generateUncached(
     messages: BaseMessageLike[][],
@@ -451,7 +464,7 @@ export abstract class BaseChatModel<
     } else {
       const inheritableMetadata = {
         ...handledOptions.metadata,
-        ...this.getLsParams(parsedOptions),
+        ...this.getLsParamsWithDefaults(parsedOptions),
       };
       const invocationParams = this?.invocationParams(parsedOptions);
       const metadataInvocationParams =
@@ -660,7 +673,7 @@ export abstract class BaseChatModel<
 
     const inheritableMetadata = {
       ...handledOptions.metadata,
-      ...this.getLsParams(parsedOptions),
+      ...this.getLsParamsWithDefaults(parsedOptions),
     };
     const invocationParams = this?.invocationParams(parsedOptions);
     const metadataInvocationParams =

libs/langchain/src/agents/ReactAgent.ts

@@ -187,7 +187,9 @@ export class ReactAgent<
     >,
     defaultConfig?: RunnableConfig
   ) {
-    this.#defaultConfig = defaultConfig ?? {};
+    this.#defaultConfig = mergeConfigs(defaultConfig ?? {}, {
+      metadata: { ls_integration: "langchain_create_agent" },
+    });
     if (options.name) {
       this.#defaultConfig = mergeConfigs(this.#defaultConfig, {
         metadata: { lc_agent_name: options.name },

libs/langchain/src/chat_models/universal.ts

@@ -363,6 +363,11 @@ export class ConfigurableModel<
       fields.queuedMethodOperations ?? this._queuedMethodOperations;
 
     this._profile = fields.profile ?? undefined;
+
+    this.metadata = {
+      ...this.metadata,
+      ls_integration: "langchain_init_chat_model",
+    };
   }
 
   async _getModelInstance(