feat(langgraph): add support for standard schema in state definition

Author: dqbd

libs/langgraph/package.json

@@ -34,6 +34,7 @@
   "dependencies": {
     "@langchain/langgraph-checkpoint": "^0.1.0",
     "@langchain/langgraph-sdk": "~0.0.105",
+    "@standard-schema/spec": "^1.0.0",
     "uuid": "^10.0.0",
     "zod": "^3.25.32"
   },

libs/langgraph/src/graph/annotation.ts

@@ -1,10 +1,20 @@
+import type { StandardSchemaV1 } from "@standard-schema/spec";
 import { RunnableLike } from "../pregel/runnable_types.js";
 import { BaseChannel } from "../channels/base.js";
 import { BinaryOperator, BinaryOperatorAggregate } from "../channels/binop.js";
 import { LastValue } from "../channels/last_value.js";
 
 export type SingleReducer<ValueType, UpdateType = ValueType> =
   | {
+      state?: StandardSchemaV1<ValueType>;
+      update?: StandardSchemaV1<UpdateType>;
+
+      jsonSchemaExtra?: {
+        langgraph_nodes?: string[];
+        langgraph_type?: "prompt" | "messages";
+        [key: string]: unknown;
+      };
+
       reducer: BinaryOperator<ValueType, UpdateType>;
       default?: () => ValueType;
     }
@@ -18,19 +28,23 @@ export type SingleReducer<ValueType, UpdateType = ValueType> =
   | null;
 
 export interface StateDefinition {
-  [key: string]: BaseChannel | (() => BaseChannel);
+  [key: string]: BaseChannel | (() => BaseChannel) | StandardSchemaV1;
 }
 
 type ExtractValueType<C> = C extends BaseChannel
   ? C["ValueType"]
   : C extends () => BaseChannel
   ? ReturnType<C>["ValueType"]
+  : C extends StandardSchemaV1
+  ? StandardSchemaV1.InferOutput<C>
   : never;
 
 type ExtractUpdateType<C> = C extends BaseChannel
   ? C["UpdateType"]
   : C extends () => BaseChannel
   ? ReturnType<C>["UpdateType"]
+  : C extends StandardSchemaV1
+  ? StandardSchemaV1.InferInput<C>
   : never;
 
 export type StateType<SD extends StateDefinition> = {

libs/langgraph/src/graph/state.ts

@@ -279,18 +279,18 @@ export class StateGraph<
     contextSchema?: C | AnnotationRoot<ToStateDefinition<C>>
   );
 
-  /** @deprecated Use `Annotation.Root` or `zod` for state definition instead. */
   constructor(
-    fields: SD extends StateDefinition
-      ? SD | StateGraphArgs<S>
-      : StateGraphArgs<S>,
+    fields: SD extends InteropZodObject
+      ? SD | ZodStateGraphArgsWithStateSchema<SD, I, O>
+      : never,
     contextSchema?: C | AnnotationRoot<ToStateDefinition<C>>
   );
 
+  /** @deprecated Use `Annotation.Root` or `zod` for state definition instead. */
   constructor(
-    fields: SD extends InteropZodObject
-      ? SD | ZodStateGraphArgsWithStateSchema<SD, I, O>
-      : never,
+    fields: SD extends StateDefinition
+      ? SD | StateGraphArgs<S>
+      : StateGraphArgs<S>,
     contextSchema?: C | AnnotationRoot<ToStateDefinition<C>>
   );
 

yarn.lock

@@ -2172,6 +2172,7 @@ __metadata:
     "@langchain/langgraph-sdk": "workspace:*"
     "@langchain/openai": "npm:^0.4.0"
     "@langchain/scripts": "npm:>=0.1.3 <0.2.0"
+    "@standard-schema/spec": "npm:^1.0.0"
     "@swc/core": "npm:^1.3.90"
     "@testing-library/dom": "npm:^10.4.0"
     "@tsconfig/recommended": "npm:^1.0.3"
@@ -3107,6 +3108,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"@standard-schema/spec@npm:^1.0.0":
+  version: 1.0.0
+  resolution: "@standard-schema/spec@npm:1.0.0"
+  checksum: 10/aee780cc1431888ca4b9aba9b24ffc8f3073fc083acc105e3951481478a2f4dc957796931b2da9e2d8329584cf211e4542275f188296c1cdff3ed44fd93a8bc8
+  languageName: node
+  linkType: hard
+
 "@swc/core-darwin-arm64@npm:1.4.16":
   version: 1.4.16
   resolution: "@swc/core-darwin-arm64@npm:1.4.16"