feat(anthropic): implement Anthropic memory tool in provider package

Author: christian-bromann

examples/src/provider/anthropic/memory.ts

@@ -0,0 +1,45 @@
+import { ChatAnthropic, tools, StateFileSystem } from "@langchain/anthropic";
+
+import { createAgent } from "langchain";
+
+const model = new ChatAnthropic({
+  model: "claude-sonnet-4-5-20250929",
+  temperature: 0,
+  clientOptions: {
+    defaultHeaders: {
+      "anthropic-beta": "context-management-2025-06-27",
+    },
+  },
+});
+
+const files = {
+  "/memories/weather_in_tokyo.txt": {
+    content: JSON.stringify({
+      weather: "sunny",
+      temperature: 20,
+      humidity: 50,
+      wind_speed: 10,
+      wind_direction: "N",
+      wind_gust: 15,
+      wind_gust_direction: "N",
+      wind_gust_speed: 20,
+      time: new Date().toISOString(),
+    }),
+    created_at: new Date().toISOString(),
+    modified_at: new Date().toISOString(),
+  },
+};
+const filesystem = new StateFileSystem(files, [], (files) => {
+  Object.assign(files, files);
+});
+
+const agent = createAgent({
+  model,
+  tools: [tools.memory({ filesystem })],
+});
+
+const result = await agent.invoke({
+  messages: "What is the weather in Tokyo?",
+});
+
+console.log(result);

libs/providers/langchain-anthropic/package.json

@@ -95,4 +95,4 @@
     "README.md",
     "LICENSE"
   ]
-}
+}

libs/providers/langchain-anthropic/src/chat_models.ts

@@ -798,6 +798,11 @@ export class ChatAnthropicMessages<
       return undefined;
     }
     return tools.map((tool) => {
+      // @ts-expect-error - tool.metadata is not typed
+      if (isLangChainTool(tool) && tool.metadata?.providerToolDefinition) {
+        // @ts-expect-error - tool.metadata is not typed
+        return tool.metadata.providerToolDefinition;
+      }
       if (isBuiltinTool(tool)) {
         return tool;
       }

libs/providers/langchain-anthropic/src/index.ts

@@ -1,3 +1,4 @@
 export * from "./chat_models.js";
 export { convertPromptToAnthropic } from "./utils/prompts.js";
 export { type ChatAnthropicContentBlock } from "./types.js";
+export * from "./tools/index.js";

libs/providers/langchain-anthropic/src/tools/index.ts

@@ -0,0 +1,9 @@
+import { memory, memory_20250818 } from "./memory.js";
+
+export type { FileSystem } from "./utils/FileSystem.js";
+export { StateFileSystem } from "./utils/StateFileSystem.js";
+
+export const tools = {
+  memory_20250818,
+  memory,
+};

libs/providers/langchain-anthropic/src/tools/memory.ts

@@ -0,0 +1,106 @@
+import { tool } from "@langchain/core/tools";
+import type { DynamicStructuredTool, ToolRuntime } from "@langchain/core/tools";
+
+import { StateFileSystem } from "./utils/StateFileSystem.js";
+import { CommandHandler } from "./utils/CommandHandler.js";
+import { handleMemoryCommand } from "./utils/index.js";
+import type { FileData } from "./utils/FileData.js";
+import type { FileSystem } from "./utils/FileSystem.js";
+import type { MemoryTool20250818Options } from "./types.js";
+
+/**
+ * Creates an Anthropic memory tool that can be used with ChatAnthropic.
+ *
+ * The memory tool enables Claude to store and retrieve information across conversations
+ * through a memory file directory. Claude can create, read, update, and delete files that
+ * persist between sessions, allowing it to build knowledge over time without keeping
+ * everything in the context window.
+ *
+ * @example
+ * ```typescript
+ * import { ChatAnthropic, memory_20250818 } from "@langchain/anthropic";
+ *
+ * const llm = new ChatAnthropic({
+ *   model: "claude-sonnet-4-5-20250929",
+ *   clientOptions: {
+ *     defaultHeaders: {
+ *       "anthropic-beta": "context-management-2025-06-27",
+ *     },
+ *   },
+ * });
+ *
+ * const memory = memory_20250818();
+ * const llmWithMemory = llm.bindTools([memory]);
+ *
+ * const response = await llmWithMemory.invoke("Remember that I like Python");
+ * ```
+ *
+ * @param options - Optional configuration for the memory tool (currently unused)
+ * @returns The memory tool object that can be passed to `bindTools`
+ *
+ * @see https://docs.anthropic.com/en/docs/agents-and-tools/tool-use/memory-tool
+ */
+export function memory_20250818(
+  options?: MemoryTool20250818Options
+): DynamicStructuredTool {
+  const memoryTool = tool(
+    options?.execute as (
+      input: unknown,
+      runtime: ToolRuntime<unknown, unknown>
+    ) => string | Promise<string>,
+    {
+      name: "memory",
+      description: "Memory tool",
+      schema: {
+        type: "object",
+        properties: {
+          command: {
+            type: "string",
+            enum: [
+              "view",
+              "create",
+              "str_replace",
+              "insert",
+              "delete",
+              "rename",
+            ],
+          },
+        },
+        required: ["command"],
+      },
+    }
+  );
+
+  memoryTool.metadata = {
+    providerToolDefinition: {
+      type: "memory_20250818",
+      name: "memory",
+    },
+  };
+
+  return memoryTool;
+}
+
+interface MemoryToolOptions {
+  allowedPrefixes?: string[];
+  filesystem?: FileSystem;
+}
+
+/**
+ * useful implementation
+ */
+export function memory(options?: MemoryToolOptions): DynamicStructuredTool {
+  const filesystem: Record<string, FileData> = {};
+  return memory_20250818({
+    execute: async (args) => {
+      const updates: Record<string, FileData | null> = {};
+      const fileSystem =
+        options?.filesystem ??
+        new StateFileSystem(filesystem, options?.allowedPrefixes, (files) => {
+          Object.assign(updates, files);
+        });
+      const commandHandler = new CommandHandler(fileSystem);
+      return await handleMemoryCommand(commandHandler, args);
+    },
+  });
+}

libs/providers/langchain-anthropic/src/tools/types.ts

@@ -0,0 +1,46 @@
+import Anthropic from "@anthropic-ai/sdk";
+
+/**
+ * Memory tool command types as defined by Anthropic's memory tool API.
+ * @see https://docs.anthropic.com/en/docs/agents-and-tools/tool-use/memory-tool
+ */
+export type MemoryCommand =
+  | MemoryViewCommand
+  | MemoryCreateCommand
+  | MemoryStrReplaceCommand
+  | MemoryInsertCommand
+  | MemoryDeleteCommand
+  | MemoryRenameCommand;
+
+export type MemoryViewCommand =
+  Anthropic.Beta.BetaMemoryTool20250818ViewCommand;
+export type MemoryCreateCommand =
+  Anthropic.Beta.BetaMemoryTool20250818CreateCommand;
+export type MemoryStrReplaceCommand =
+  Anthropic.Beta.BetaMemoryTool20250818StrReplaceCommand;
+export type MemoryInsertCommand =
+  Anthropic.Beta.BetaMemoryTool20250818InsertCommand;
+export type MemoryDeleteCommand =
+  Anthropic.Beta.BetaMemoryTool20250818DeleteCommand;
+export type MemoryRenameCommand =
+  Anthropic.Beta.BetaMemoryTool20250818RenameCommand;
+
+/**
+ * Options for creating a memory tool.
+ */
+export interface MemoryTool20250818Options {
+  /**
+   * Optional execute function that handles memory command execution.
+   * In LangChain, this is typically handled separately when processing tool calls,
+   * but this option is provided for compatibility with the AI SDK pattern.
+   * Note: This option is currently unused but reserved for future use.
+   */
+  execute?: (
+    action: Anthropic.Beta.BetaMemoryTool20250818Command
+  ) => Promise<string> | string;
+}
+
+/**
+ * Memory tool type definition.
+ */
+export type MemoryTool = Anthropic.Beta.BetaMemoryTool20250818;