cacheplane · blove · May 8, 2026 · May 7, 2026 · May 7, 2026 · May 7, 2026
diff --git a/apps/website/content/docs/agent/api/api-docs.json b/apps/website/content/docs/agent/api/api-docs.json
@@ -173,7 +173,7 @@
       },
       {
         "name": "updateState",
-        "signature": "updateState(threadId: string, values: Record<string, unknown>, _signal: AbortSignal)",
+        "signature": "updateState(threadId: string, values: Record<string, unknown>, _signal: AbortSignal, options: object)",
         "description": "Update server-side thread state, e.g. to remove messages for regenerate rollback.",
         "params": [
           {
@@ -193,6 +193,12 @@
             "type": "AbortSignal",
             "description": "",
             "optional": false
+          },
+          {
+            "name": "options",
+            "type": "object",
+            "description": "",
+            "optional": true
           }
         ]
       }

diff --git a/libs/a2ui/package.json b/libs/a2ui/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@ngaf/a2ui",
-  "version": "0.0.28",
+  "version": "0.0.29",
   "license": "MIT",
   "repository": {
     "type": "git",

diff --git a/libs/ag-ui/package.json b/libs/ag-ui/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@ngaf/ag-ui",
-  "version": "0.0.28",
+  "version": "0.0.29",
   "peerDependencies": {
     "@ngaf/chat": "*",
     "@ngaf/licensing": "*",

diff --git a/libs/chat/package.json b/libs/chat/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@ngaf/chat",
-  "version": "0.0.28",
+  "version": "0.0.29",
   "exports": {
     ".": {
       "types": "./index.d.ts",
@@ -13,7 +13,7 @@
     "./chat.css": "./chat.css"
   },
   "dependencies": {
-    "@cacheplane/partial-json": "^0.1.1",
+    "@cacheplane/partial-json": ">=0.1.1 <0.3.0",
     "@cacheplane/partial-markdown": "^0.3.0"
   },
   "peerDependencies": {

diff --git a/libs/cockpit-docs/package.json b/libs/cockpit-docs/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@ngaf/cockpit-docs",
-  "version": "0.0.28",
+  "version": "0.0.29",
   "license": "MIT",
   "repository": {
     "type": "git",

diff --git a/libs/cockpit-registry/package.json b/libs/cockpit-registry/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@ngaf/cockpit-registry",
-  "version": "0.0.28",
+  "version": "0.0.29",
   "license": "MIT",
   "repository": {
     "type": "git",

diff --git a/libs/cockpit-shell/package.json b/libs/cockpit-shell/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@ngaf/cockpit-shell",
-  "version": "0.0.28",
+  "version": "0.0.29",
   "license": "MIT",
   "repository": {
     "type": "git",

diff --git a/libs/cockpit-testing/package.json b/libs/cockpit-testing/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@ngaf/cockpit-testing",
-  "version": "0.0.28",
+  "version": "0.0.29",
   "license": "MIT",
   "repository": {
     "type": "git",

diff --git a/libs/cockpit-ui/package.json b/libs/cockpit-ui/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@ngaf/cockpit-ui",
-  "version": "0.0.28",
+  "version": "0.0.29",
   "license": "MIT",
   "repository": {
     "type": "git",

diff --git a/libs/db/package.json b/libs/db/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@ngaf/db",
-  "version": "0.0.28",
+  "version": "0.0.29",
   "license": "MIT",
   "repository": {
     "type": "git",

diff --git a/libs/design-tokens/package.json b/libs/design-tokens/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@ngaf/design-tokens",
-  "version": "0.0.28",
+  "version": "0.0.29",
   "license": "MIT",
   "repository": {
     "type": "git",

diff --git a/libs/example-layouts/package.json b/libs/example-layouts/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@ngaf/example-layouts",
-  "version": "0.0.28",
+  "version": "0.0.29",
   "peerDependencies": {
     "@angular/core": "^20.0.0 || ^21.0.0",
     "@angular/common": "^20.0.0 || ^21.0.0"

diff --git a/libs/langgraph/package.json b/libs/langgraph/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@ngaf/langgraph",
-  "version": "0.0.28",
+  "version": "0.0.29",
   "peerDependencies": {
     "@ngaf/chat": "*",
     "@ngaf/licensing": "*",

diff --git a/libs/langgraph/src/lib/agent.fn.spec.ts b/libs/langgraph/src/lib/agent.fn.spec.ts
@@ -747,6 +747,60 @@ describe('agent', () => {
       expect(seen[1]?.payload).toBeNull();
     });
 
+    it("forwards asNode: '__start__' to transport.updateState so the next submit(null) can resume", async () => {
+      // After the original run the LangGraph thread sits at __end__ with
+      // `next: []`. submit(null) is a no-op in that position. The regenerate
+      // flow has to reposition the thread via `as_node='__start__'` before
+      // re-running, so the transport must receive that option.
+      const updateCalls: Array<{
+        threadId: string;
+        values: Record<string, unknown>;
+        options?: { asNode?: string };
+      }> = [];
+      const transport = new MockAgentTransport();
+      // Augment the mock with an updateState capture.
+      (transport as unknown as {
+        updateState: (
+          threadId: string,
+          values: Record<string, unknown>,
+          signal: AbortSignal,
+          options?: { asNode?: string },
+        ) => Promise<void>;
+      }).updateState = async (threadId, values, _signal, options) => {
+        updateCalls.push({ threadId, values, options });
+      };
+
+      const ref = withInjectionContext(() =>
+        agent({ apiUrl: '', assistantId: 'a', threadId: 't-1', transport, throttle: false })
+      );
+
+      ref.submit({ message: 'hello' });
+      transport.emit([{
+        type: 'messages',
+        messages: [
+          { id: 'u-1', type: 'human', content: 'hello' },
+          { id: 'a-1', type: 'ai', content: 'hi there' },
+        ],
+      }]);
+      transport.close();
+      await new Promise(r => setTimeout(r, 30));
+
+      const regeneratePromise = ref.regenerate(1);
+      transport.close();
+      await regeneratePromise;
+
+      // updateState invoked exactly once — with the RemoveMessage payload
+      // AND asNode set to '__start__'. Without asNode, regenerate would
+      // submit(null) against a terminal thread and produce no new assistant.
+      expect(updateCalls).toHaveLength(1);
+      expect(updateCalls[0]?.threadId).toBe('t-1');
+      expect(updateCalls[0]?.options?.asNode).toBe('__start__');
+      const removeMessages = (updateCalls[0]?.values?.['messages'] as Array<Record<string, unknown>>) ?? [];
+      expect(removeMessages).toHaveLength(1);
+      expect(removeMessages[0]?.['type']).toBe('remove');
+      expect(removeMessages[0]?.['id']).toBe('a-1');
+    });
+
     it('throws when target index is not an assistant message', async () => {
       const transport = new MockAgentTransport();
       const ref = withInjectionContext(() =>

diff --git a/libs/langgraph/src/lib/agent.fn.ts b/libs/langgraph/src/lib/agent.fn.ts
@@ -310,15 +310,26 @@ export function agent<
         })
         .filter((rm): rm is RemoveMessageInstruction => rm !== null);
 
-      if (removeList.length > 0) {
-        // updateState is a no-op when the transport doesn't support it
-        // (e.g. mock transport in unit tests) — safe to call unconditionally.
-        await manager.updateState({ messages: removeList });
-      }
-
-      // Re-run the graph with no new input so LangGraph executes from the
-      // current (trimmed) thread state. The trailing user message becomes the
-      // active prompt without being re-appended.
+      // RemoveMessage rollback + reposition the graph to the entry node
+      // via `as_node: '__start__'`. After the original run, the thread is
+      // at `__end__` with `next: []` — submitting `null` would be a no-op
+      // because there is nothing pending to execute. Setting `asNode` to
+      // the start node tells LangGraph to treat the update as if `__start__`
+      // had just produced the values, so the next pull resumes at the entry
+      // node and runs `generate` against the rolled-back state.
+      //
+      // We always pass `asNode` even when removeList is empty (rare, but
+      // possible if the assistant message had no id) so the regenerate
+      // submit below still runs the graph.
+      await manager.updateState(
+        { messages: removeList },
+        { asNode: '__start__' },
+      );
+
+      // Re-run the graph with no new input. With the thread now repositioned
+      // at `__start__`, this resumes at the entry node and produces a fresh
+      // assistant message — the trailing user message becomes the active
+      // prompt without being re-appended.
       await manager.submit(null, undefined);
     },
 

diff --git a/libs/langgraph/src/lib/agent.types.ts b/libs/langgraph/src/lib/agent.types.ts
@@ -212,11 +212,18 @@ export interface AgentTransport {
    * Optional: update server-side thread state (e.g. to emit RemoveMessage
    * entries for regenerate rollback). Forwards to the LangGraph
    * `threads.updateState` API.
+   *
+   * `options.asNode` corresponds to LangGraph's `as_node` parameter — the
+   * server treats the update as if that node had just produced the values,
+   * which determines what the next pull resumes. `regenerate()` passes
+   * `asNode: '__start__'` so the next `submit(null)` resumes at the entry
+   * node and re-runs `generate` against the rolled-back state.
    */
   updateState?(
     threadId: string,
     values: Record<string, unknown>,
     signal: AbortSignal,
+    options?: { asNode?: string },
   ): Promise<void>;
 }
 
@@ -312,11 +319,13 @@ export interface LangGraphAgent<T = unknown, ResolvedBag extends BagTemplate = B
   reload: () => void;
 
   /**
-   * Truncate the thread at the given assistant-message index and re-submit the
-   * preceding user message. Used by `<ngaf-chat>`'s regenerate action and any
-   * custom UI that wants the same semantics. Rejects if the agent is currently
-   * loading, if the index does not point at an assistant message, or if no
-   * preceding user message exists.
+   * Discards the assistant message at the given index AND all messages after
+   * it, then re-runs the agent against the trimmed conversation tail. The
+   * preceding user message (at index - 1) is preserved and re-submitted as
+   * the agent's input. No new user message is added to the history.
+   *
+   * Throws if the message at `index` is not 'assistant' role, or if the
+   * agent is currently loading another response.
    */
   regenerate: (assistantMessageIndex: number) => Promise<void>;
 

diff --git a/libs/langgraph/src/lib/internals/stream-manager.bridge.ts b/libs/langgraph/src/lib/internals/stream-manager.bridge.ts
@@ -55,7 +55,7 @@ export interface StreamManagerBridge {
   resubmitLast:          () => Promise<void>;
   getReasoningDurationMs:(id: string) => number | undefined;
   /** Update server-side thread state (e.g. RemoveMessage for regenerate rollback). */
-  updateState:           (values: Record<string, unknown>) => Promise<void>;
+  updateState:           (values: Record<string, unknown>, opts?: { asNode?: string }) => Promise<void>;
   /** The current thread ID tracked by the bridge (null if not yet known). */
   readonly currentThreadId: string | null;
 }
@@ -665,13 +665,21 @@ export function createStreamManagerBridge<T, ResolvedBag extends BagTemplate = B
       return entry.endedAt - entry.startedAt;
     },
 
-    updateState: async (values: Record<string, unknown>): Promise<void> => {
+    updateState: async (
+      values: Record<string, unknown>,
+      opts?: { asNode?: string },
+    ): Promise<void> => {
       // No-op when there is no thread yet or the transport doesn't support
       // updateState (e.g. MockAgentTransport in unit tests without a threadId).
       if (!currentThreadId || !transport.updateState) {
         return;
       }
-      await transport.updateState(currentThreadId, values, new AbortController().signal);
+      await transport.updateState(
+        currentThreadId,
+        values,
+        new AbortController().signal,
+        opts,
+      );
     },
 
     get currentThreadId(): string | null {

diff --git a/libs/langgraph/src/lib/transport/fetch-stream.transport.ts b/libs/langgraph/src/lib/transport/fetch-stream.transport.ts
@@ -115,8 +115,17 @@ export class FetchStreamTransport implements AgentTransport {
   }
 
   /** Update server-side thread state, e.g. to remove messages for regenerate rollback. */
-  async updateState(threadId: string, values: Record<string, unknown>, _signal: AbortSignal): Promise<void> {
-    await this.client.threads.updateState(threadId, { values });
+  async updateState(
+    threadId: string,
+    values: Record<string, unknown>,
+    _signal: AbortSignal,
+    options?: { asNode?: string },
+  ): Promise<void> {
+    const body: { values: Record<string, unknown>; asNode?: string } = { values };
+    if (options?.asNode !== undefined) {
+      body.asNode = options.asNode;
+    }
+    await this.client.threads.updateState(threadId, body);
   }
 }
 

diff --git a/libs/licensing/package.json b/libs/licensing/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@ngaf/licensing",
-  "version": "0.0.28",
+  "version": "0.0.29",
   "license": "MIT",
   "repository": {
     "type": "git",

diff --git a/libs/partial-json/package.json b/libs/partial-json/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@ngaf/partial-json",
-  "version": "0.0.28",
+  "version": "0.0.29",
   "deprecated": "Replaced by @cacheplane/partial-json. No further versions will be published from this package.",
   "license": "MIT",
   "repository": {

diff --git a/libs/render/package.json b/libs/render/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@ngaf/render",
-  "version": "0.0.28",
+  "version": "0.0.29",
   "peerDependencies": {
     "@angular/core": "^20.0.0 || ^21.0.0",
     "@angular/common": "^20.0.0 || ^21.0.0",

diff --git a/libs/ui-react/package.json b/libs/ui-react/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@ngaf/ui-react",
-  "version": "0.0.28",
+  "version": "0.0.29",
   "license": "MIT",
   "repository": {
     "type": "git",