fix(langgraph): drop 'tools' stream_mode + content-match id preservation

libs/langgraph/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@ngaf/langgraph",
-  "version": "0.0.4",
+  "version": "0.0.6",
   "peerDependencies": {
     "@ngaf/chat": "*",
     "@ngaf/licensing": "*",

libs/langgraph/src/lib/internals/stream-manager.bridge.ts

@@ -337,7 +337,9 @@ export function createStreamManagerBridge<T, ResolvedBag extends BagTemplate = B
         // batch shouldn't tear down the entire UI (causes message DOM
         // teardown + streaming renderer reset = visible jank).
       } else {
-        subjects.messages$.next(normalized);
+        // Preserve existing ids by content so the final-id swap doesn't
+        // tear down the chat-message DOM (and its streaming-md renderer).
+        subjects.messages$.next(preserveIds(subjects.messages$.value, normalized));
       }
       storeMessageMetadata(normalized, event);
       syncSubagentsFromMessages(normalized);
@@ -363,11 +365,16 @@ export function createStreamManagerBridge<T, ResolvedBag extends BagTemplate = B
           if (Array.isArray(stateMessages) && stateMessages.length > 0) {
             // Defensive: only sync when state carries messages. An empty
             // values payload shouldn't wipe the UI mid-stream.
-            if (options.toMessage) {
-              subjects.messages$.next(stateMessages.map(options.toMessage));
-            } else {
-              subjects.messages$.next(stateMessages as BaseMessage[]);
-            }
+            const projected = options.toMessage
+              ? stateMessages.map(options.toMessage)
+              : (stateMessages as BaseMessage[]);
+            // Preserve existing message ids when content matches. Server-
+            // echoed human messages and final AI messages often arrive with
+            // different ids than the optimistic / partial we already have —
+            // letting that id swap reach chat-message-list's track-by-id
+            // tears down DOM mid-stream. preserveIds maps new messages to
+            // existing-id-by-content where possible.
+            subjects.messages$.next(preserveIds(subjects.messages$.value, projected));
             syncSubagentsFromMessages(stateMessages as BaseMessage[]);
             subagentManager.reconstructFromMessages(
               stateMessages as BaseMessage[],
@@ -670,16 +677,93 @@ function mergeMessages(existing: BaseMessage[], incoming: BaseMessage[]): BaseMe
   const merged = [...existing];
   for (const msg of incoming) {
     const id = (msg as unknown as Record<string, unknown>)['id'];
-    const idx = id ? merged.findIndex(m => (m as unknown as Record<string, unknown>)['id'] === id) : -1;
+    let idx = id ? merged.findIndex(m => (m as unknown as Record<string, unknown>)['id'] === id) : -1;
+    // Fallback: match by (role, content) when ids differ. This is the path
+    // that fires when the server echoes back our optimistic human message
+    // with a server-assigned id, or when partial AI tokens carry a chunk
+    // id but the final canonical message has a run id. Preserving the
+    // existing id here keeps track-by-id stable in the chat list and
+    // prevents DOM teardown + animation restarts mid-stream.
+    if (idx < 0) {
+      idx = findContentMatch(merged, msg);
+    }
     if (idx >= 0) {
-      merged[idx] = msg;
+      const existingId = (merged[idx] as unknown as Record<string, unknown>)['id'];
+      // Keep the *existing* id so downstream track-by-id sees stable identity.
+      // The replacement carries the latest content + metadata.
+      merged[idx] = existingId
+        ? ({ ...(msg as object), id: existingId } as BaseMessage)
+        : msg;
     } else {
       merged.push(msg);
     }
   }
   return merged;
 }
 
+/**
+ * Replace the incoming messages' ids with the existing array's ids whenever
+ * (role, content) matches positionally and the existing id differs. Keeps
+ * track-by-id stable across server echoes and final-id swaps.
+ */
+function preserveIds(existing: BaseMessage[], incoming: BaseMessage[]): BaseMessage[] {
+  if (existing.length === 0) return incoming;
+  const usedExisting = new Set<number>();
+  return incoming.map((msg, i) => {
+    const inRaw = msg as unknown as Record<string, unknown>;
+    const inId = inRaw['id'];
+    // First try same-position match (the dominant case).
+    let matchIdx = -1;
+    if (i < existing.length && !usedExisting.has(i) && sameRoleAndContent(existing[i], msg)) {
+      matchIdx = i;
+    } else {
+      // Fallback: any unused existing message with matching role+content.
+      matchIdx = existing.findIndex((m, j) => !usedExisting.has(j) && sameRoleAndContent(m, msg));
+    }
+    if (matchIdx < 0) return msg;
+    usedExisting.add(matchIdx);
+    const existingId = (existing[matchIdx] as unknown as Record<string, unknown>)['id'];
+    if (!existingId || existingId === inId) return msg;
+    return { ...(msg as object), id: existingId } as BaseMessage;
+  });
+}
+
+function sameRoleAndContent(a: BaseMessage, b: BaseMessage): boolean {
+  const aType = typeof a._getType === 'function' ? a._getType() : (a as unknown as Record<string, unknown>)['type'];
+  const bType = typeof b._getType === 'function' ? b._getType() : (b as unknown as Record<string, unknown>)['type'];
+  if (aType !== bType) return false;
+  const aContent = typeof a.content === 'string' ? a.content : JSON.stringify(a.content);
+  const bContent = typeof b.content === 'string' ? b.content : JSON.stringify(b.content);
+  if (aContent === bContent) return true;
+  // For AI messages we accept prefix relationships (streaming → final).
+  if (aType === 'ai' && typeof aContent === 'string' && typeof bContent === 'string') {
+    return aContent.length > 0 && (bContent.startsWith(aContent) || aContent.startsWith(bContent));
+  }
+  return false;
+}
+
+function findContentMatch(merged: BaseMessage[], incoming: BaseMessage): number {
+  const inRaw = incoming as unknown as Record<string, unknown>;
+  const inType = typeof incoming._getType === 'function' ? incoming._getType() : (inRaw['type'] as string | undefined);
+  const inContent = typeof incoming.content === 'string' ? incoming.content : JSON.stringify(incoming.content);
+  // Only worth matching for human messages (where the optimistic→echo
+  // mismatch happens) and for AI messages where content is a strict prefix
+  // of the existing (token-streaming + final-id swap pattern).
+  for (let i = merged.length - 1; i >= 0; i--) {
+    const m = merged[i] as unknown as Record<string, unknown>;
+    const mType = typeof (merged[i] as BaseMessage)._getType === 'function'
+      ? (merged[i] as BaseMessage)._getType()
+      : (m['type'] as string | undefined);
+    if (mType !== inType) continue;
+    const mContent = typeof (merged[i] as BaseMessage).content === 'string'
+      ? (merged[i] as BaseMessage).content as string
+      : JSON.stringify((merged[i] as BaseMessage).content);
+    if (inType === 'human' && mContent === inContent) return i;
+    if (inType === 'ai' && (mContent === inContent || (typeof mContent === 'string' && typeof inContent === 'string' && (inContent.startsWith(mContent) || mContent.startsWith(inContent))))) return i;
+  }
+  return -1;
+}
+
 function toSubagentRefs(
   subagents: Map<string, TrackedSubagent>,
 ): Map<string, SubagentStreamRef> {

libs/langgraph/src/lib/transport/fetch-stream.transport.spec.ts

@@ -69,7 +69,7 @@ describe('FetchStreamTransport', () => {
     ]);
   });
 
-  it('requests the stream modes required for values, messages, tools, and custom events', async () => {
+  it('requests the stream modes required for values, messages, and custom events', async () => {
     mocks.runsStream.mockReturnValue((async function* () {
       yield { event: 'metadata', data: { run_id: 'run-1', thread_id: 'thread-1' } };
     })());
@@ -87,7 +87,6 @@ describe('FetchStreamTransport', () => {
           'values',
           'messages-tuple',
           'updates',
-          'tools',
           'custom',
         ]),
       }),

libs/langgraph/src/lib/transport/fetch-stream.transport.ts

@@ -147,7 +147,11 @@ function buildRunPayload(
 }
 
 function defaultStreamMode(): StreamMode[] {
-  return ['values', 'messages-tuple', 'updates', 'tools', 'custom'];
+  // 'tools' is intentionally omitted: not supported by langgraph_api < 0.9.x
+  // Servers reject the entire request with HTTP 422 if any stream_mode in
+  // the array is unknown to them. Tool-call data is still derivable from
+  // the messages stream.
+  return ['values', 'messages-tuple', 'updates', 'custom'];
 }
 
 function normalizeSdkEvent(type: StreamEvent['type'], data: unknown): StreamEvent {