diff --git a/packages/core/src/context/graph/toGraph.ts b/packages/core/src/context/graph/toGraph.ts
index 51012fed04..454c867fb8 100644
--- a/packages/core/src/context/graph/toGraph.ts
+++ b/packages/core/src/context/graph/toGraph.ts
@@ -6,7 +6,7 @@
 
 import type { Part } from '@google/genai';
 import { type ConcreteNode, NodeType } from './types.js';
-import { randomUUID, createHash } from 'node:crypto';
+import { createHash } from 'node:crypto';
 import { debugLogger } from '../../utils/debugLogger.js';
 import type { NodeIdService } from './nodeIdService.js';
 import type { HistoryTurn } from '../../core/agentChatHistory.js';
@@ -157,7 +157,7 @@ export function getStableId(
     if (turnSalt && partIdx === -1) {
       id = `turn_${turnSalt}`;
     } else {
-      id = randomUUID();
+      id = `${turnSalt}_f_${partIdx}`;
     }
   }
 
diff --git a/packages/core/src/context/processors/blobDegradationProcessor.ts b/packages/core/src/context/processors/blobDegradationProcessor.ts
index c1cae0d0a6..663d26aba7 100644
--- a/packages/core/src/context/processors/blobDegradationProcessor.ts
+++ b/packages/core/src/context/processors/blobDegradationProcessor.ts
@@ -3,7 +3,7 @@
  * Copyright 2026 Google LLC
  * SPDX-License-Identifier: Apache-2.0
  */
-import { randomUUID } from 'node:crypto';
+import { deriveStableId } from '../../utils/cryptoUtils.js';
 import type { JSONSchemaType } from 'ajv';
 import type { ProcessArgs, ContextProcessor } from '../pipeline.js';
 import * as fs from 'node:fs/promises';
@@ -62,7 +62,8 @@ export function createBlobDegradationProcessor(
         if (payload.inlineData?.data && payload.inlineData?.mimeType) {
           await ensureDir();
           const ext = payload.inlineData.mimeType.split('/')[1] || 'bin';
-          const fileName = `blob_${Date.now()}_${randomUUID()}.${ext}`;
+          // Use a stable filename based on the node ID
+          const fileName = `blob_${deriveStableId([node.id])}.${ext}`;
           const filePath = path.join(blobOutputsDir, fileName);
 
           const buffer = Buffer.from(payload.inlineData.data, 'base64');
@@ -92,7 +93,7 @@ export function createBlobDegradationProcessor(
         if (newText && tokensSaved > 0) {
           returnedNodes.push({
             ...node,
-            id: randomUUID(),
+            id: deriveStableId([node.id, 'degraded']),
             payload: { text: newText },
             replacesId: node.id,
             turnId: node.turnId,
diff --git a/packages/core/src/context/processors/nodeDistillationProcessor.ts b/packages/core/src/context/processors/nodeDistillationProcessor.ts
index 5691ddf51b..a6a818ed56 100644
--- a/packages/core/src/context/processors/nodeDistillationProcessor.ts
+++ b/packages/core/src/context/processors/nodeDistillationProcessor.ts
@@ -3,7 +3,7 @@
  * Copyright 2026 Google LLC
  * SPDX-License-Identifier: Apache-2.0
  */
-import { randomUUID } from 'node:crypto';
+import { deriveStableId } from '../../utils/cryptoUtils.js';
 import type { JSONSchemaType } from 'ajv';
 import type { ContextProcessor, ProcessArgs } from '../pipeline.js';
 import { type ConcreteNode, NodeType } from '../graph/types.js';
@@ -99,9 +99,10 @@ export function createNodeDistillationProcessor(
               if (newTokens < oldTokens) {
                 const distilledPayload = updatePart(payload, { text: summary });
 
+                const newId = deriveStableId([node.id, 'distilled']);
                 returnedNodes.push({
                   ...node,
-                  id: randomUUID(),
+                  id: newId,
                   payload: distilledPayload,
                   replacesId: node.id,
                   timestamp: node.timestamp,
@@ -158,9 +159,10 @@ export function createNodeDistillationProcessor(
                     functionResponse: newFR,
                   });
 
+                  const newId = deriveStableId([node.id, 'distilled']);
                   returnedNodes.push({
                     ...node,
-                    id: randomUUID(),
+                    id: newId,
                     payload: distilledPayload,
                     replacesId: node.id,
                     timestamp: node.timestamp,
diff --git a/packages/core/src/context/processors/nodeTruncationProcessor.ts b/packages/core/src/context/processors/nodeTruncationProcessor.ts
index acb08e2022..75f74f60cf 100644
--- a/packages/core/src/context/processors/nodeTruncationProcessor.ts
+++ b/packages/core/src/context/processors/nodeTruncationProcessor.ts
@@ -3,7 +3,7 @@
  * Copyright 2026 Google LLC
  * SPDX-License-Identifier: Apache-2.0
  */
-import { randomUUID } from 'node:crypto';
+import { deriveStableId } from '../../utils/cryptoUtils.js';
 import type { JSONSchemaType } from 'ajv';
 import type { ContextProcessor, ProcessArgs } from '../pipeline.js';
 import type { ContextEnvironment } from '../pipeline/environment.js';
@@ -79,9 +79,10 @@ export function createNodeTruncationProcessor(
         if (text) {
           const squashResult = tryApplySquash(text, limitChars);
           if (squashResult) {
+            const newId = deriveStableId([node.id, 'truncated']);
             returnedNodes.push({
               ...node,
-              id: randomUUID(),
+              id: newId,
               payload: { ...payload, text: squashResult.text },
               replacesId: node.id,
               turnId: node.turnId,
diff --git a/packages/core/src/context/processors/rollingSummaryProcessor.ts b/packages/core/src/context/processors/rollingSummaryProcessor.ts
index fc6f5cb60a..5de111e0f8 100644
--- a/packages/core/src/context/processors/rollingSummaryProcessor.ts
+++ b/packages/core/src/context/processors/rollingSummaryProcessor.ts
@@ -3,7 +3,7 @@
  * Copyright 2026 Google LLC
  * SPDX-License-Identifier: Apache-2.0
  */
-import { randomUUID } from 'node:crypto';
+import { deriveStableId } from '../../utils/cryptoUtils.js';
 import type { JSONSchemaType } from 'ajv';
 import type {
   ContextProcessor,
@@ -112,7 +112,8 @@ export function createRollingSummaryProcessor(
       try {
         // Synthesize the rolling summary synchronously
         const snapshotText = await generateRollingSummary(nodesToSummarize);
-        const newId = randomUUID();
+        const consumedIds = nodesToSummarize.map((n) => n.id);
+        const newId = deriveStableId(consumedIds);
 
         const summaryNode: RollingSummary = {
           id: newId,
@@ -121,10 +122,9 @@ export function createRollingSummaryProcessor(
           timestamp: nodesToSummarize[nodesToSummarize.length - 1].timestamp,
           role: 'user',
           payload: { text: snapshotText },
-          abstractsIds: nodesToSummarize.map((n) => n.id),
+          abstractsIds: consumedIds,
         };
 
-        const consumedIds = nodesToSummarize.map((n) => n.id);
         const returnedNodes = targets.filter(
           (t) => !consumedIds.includes(t.id),
         );
diff --git a/packages/core/src/context/processors/stateSnapshotProcessor.ts b/packages/core/src/context/processors/stateSnapshotProcessor.ts
index 52ab8f5338..b57f4f7960 100644
--- a/packages/core/src/context/processors/stateSnapshotProcessor.ts
+++ b/packages/core/src/context/processors/stateSnapshotProcessor.ts
@@ -3,7 +3,7 @@
  * Copyright 2026 Google LLC
  * SPDX-License-Identifier: Apache-2.0
  */
-import { createHash } from 'node:crypto';
+import { deriveStableId } from '../../utils/cryptoUtils.js';
 import type { JSONSchemaType } from 'ajv';
 import type {
   ContextProcessor,
@@ -50,13 +50,6 @@ export function createStateSnapshotProcessor(
 ): ContextProcessor {
   const generator = new SnapshotGenerator(env);
 
-  const generateStableId = (consumedIds: string[]) => {
-    return createHash('sha256')
-      .update(consumedIds.sort().join(','))
-      .digest('hex')
-      .slice(0, 32);
-  };
-
   return {
     id,
     name: 'StateSnapshotProcessor',
@@ -101,7 +94,7 @@ export function createStateSnapshotProcessor(
               `[StateSnapshotProcessor] Successfully spliced PROPOSED_SNAPSHOT from Inbox into Graph. Consumed ${consumedIds.length} nodes.`,
             );
             // If valid, apply it!
-            const newId = generateStableId(consumedIds);
+            const newId = deriveStableId(consumedIds);
 
             const snapshotNode: Snapshot = {
               id: newId,
@@ -197,7 +190,7 @@ export function createStateSnapshotProcessor(
         if (baselineIdToConsume && !consumedIds.includes(baselineIdToConsume)) {
           consumedIds.push(baselineIdToConsume);
         }
-        const newId = generateStableId(consumedIds);
+        const newId = deriveStableId(consumedIds);
 
         const snapshotNode: Snapshot = {
           id: newId,
diff --git a/packages/core/src/context/processors/toolMaskingProcessor.ts b/packages/core/src/context/processors/toolMaskingProcessor.ts
index e62bb34e5d..43aba6e40b 100644
--- a/packages/core/src/context/processors/toolMaskingProcessor.ts
+++ b/packages/core/src/context/processors/toolMaskingProcessor.ts
@@ -3,7 +3,7 @@
  * Copyright 2026 Google LLC
  * SPDX-License-Identifier: Apache-2.0
  */
-import { randomUUID } from 'node:crypto';
+import { deriveStableId } from '../../utils/cryptoUtils.js';
 import type { JSONSchemaType } from 'ajv';
 import type { ContextProcessor, ProcessArgs } from '../pipeline.js';
 import * as fs from 'node:fs/promises';
@@ -120,7 +120,7 @@ export function createToolMaskingProcessor(
           directoryCreated = true;
         }
 
-        const fileName = `${sanitizeFilenamePart(toolName).toLowerCase()}_${sanitizeFilenamePart(callId).toLowerCase()}_${nodeType}_${randomUUID()}.txt`;
+        const fileName = `${sanitizeFilenamePart(toolName).toLowerCase()}_${sanitizeFilenamePart(callId).toLowerCase()}_${nodeType}_${deriveStableId([content])}.txt`;
         const filePath = path.join(toolOutputsDir, fileName);
 
         await fs.writeFile(filePath, content);
@@ -214,9 +214,10 @@ export function createToolMaskingProcessor(
                 functionCall: newFC,
               });
 
+              const newId = deriveStableId([node.id, 'masked']);
               returnedNodes.push({
                 ...node,
-                id: randomUUID(),
+                id: newId,
                 payload: maskedPart,
                 replacesId: node.id,
                 turnId: node.turnId,
@@ -242,9 +243,10 @@ export function createToolMaskingProcessor(
                 functionResponse: newFR,
               });
 
+              const newId = deriveStableId([node.id, 'masked']);
               returnedNodes.push({
                 ...node,
-                id: randomUUID(),
+                id: newId,
                 payload: maskedPart,
                 replacesId: node.id,
                 turnId: node.turnId,
diff --git a/packages/core/src/core/client.ts b/packages/core/src/core/client.ts
index ce99fb37bc..ef7188dbfc 100644
--- a/packages/core/src/core/client.ts
+++ b/packages/core/src/core/client.ts
@@ -296,13 +296,7 @@ export class GeminiClient {
   }
 
   setHistory(history: readonly (Content | HistoryTurn)[]) {
-    const turns = history.map((item) => {
-      if ('id' in item && 'content' in item) {
-        return item as HistoryTurn;
-      }
-      return { id: randomUUID(), content: item as Content };
-    });
-    this.getChat().setHistory(turns);
+    this.getChat().setHistory(history);
     this.updateTelemetryTokenCount();
     this.forceFullIdeContext = true;
   }
@@ -651,7 +645,11 @@ export class GeminiClient {
       if (this.contextManager) {
         const rawPendingRequest = createUserContent(request);
         const pendingRequest = {
-          id: randomUUID(),
+          id:
+            this.getChatRecordingService()?.recordSyntheticMessage(
+              'user',
+              rawPendingRequest.parts || [],
+            ) || randomUUID(),
           content: rawPendingRequest,
         };
         const {
@@ -678,11 +676,7 @@ export class GeminiClient {
           signal,
         );
         if (newHistory.length !== this.getHistory().length) {
-          const turns = newHistory.map((c) => ({
-            id: randomUUID(),
-            content: c,
-          }));
-          this.getChat().setHistory(turns);
+          this.getChat().setHistory(newHistory);
         }
       }
     } else {
@@ -1242,11 +1236,7 @@ export class GeminiClient {
       if (newHistory) {
         // We truncated content to save space, but summarization is still "failed".
         // We update the chat context directly without resetting the failure flag.
-        const turns = newHistory.map((c) => ({
-          id: randomUUID(),
-          content: c,
-        }));
-        this.getChat().setHistory(turns);
+        this.getChat().setHistory(newHistory);
         this.updateTelemetryTokenCount();
         // We don't reset the chat session fully like in COMPRESSED because
         // this is a lighter-weight intervention.
@@ -1265,11 +1255,7 @@ export class GeminiClient {
       this.config,
     );
     if (result.maskedCount > 0) {
-      const turns = result.newHistory.map((c) => ({
-        id: randomUUID(),
-        content: c,
-      }));
-      this.getChat().setHistory(turns);
+      this.getChat().setHistory(result.newHistory);
     }
   }
 
diff --git a/packages/core/src/core/geminiChat.ts b/packages/core/src/core/geminiChat.ts
index 5f6b8f6a69..bb90504f24 100644
--- a/packages/core/src/core/geminiChat.ts
+++ b/packages/core/src/core/geminiChat.ts
@@ -323,6 +323,9 @@ export class GeminiChat {
     kind: 'main' | 'subagent' = 'main',
   ) {
     await this.chatRecordingService.initialize(resumedSessionData, kind);
+    // Sync initial history with the recorder to ensure all turns (even bootstrapped ones)
+    // are durable and coordinated.
+    this.chatRecordingService.updateMessagesFromHistory(this.agentHistory.get());
   }
 
   setSystemInstruction(sysInstr: string) {
@@ -913,7 +916,11 @@ export class GeminiChat {
     if ('id' in content && 'content' in content) {
       this.agentHistory.push(content);
     } else {
-      this.agentHistory.push({ id: randomUUID(), content });
+      const id = this.chatRecordingService.recordSyntheticMessage(
+        content.role === 'user' ? 'user' : 'gemini',
+        content.parts || [],
+      );
+      this.agentHistory.push({ id, content });
     }
   }
 
@@ -921,11 +928,16 @@ export class GeminiChat {
     history: readonly (Content | HistoryTurn)[],
     options: { silent?: boolean } = {},
   ): void {
-    const wrappedHistory: HistoryTurn[] = history.map((item) =>
-      'id' in item && 'content' in item
-        ? item
-        : { id: randomUUID(), content: item },
-    );
+    const wrappedHistory: HistoryTurn[] = history.map((item) => {
+      if ('id' in item && 'content' in item) {
+        return item;
+      }
+      const id = this.chatRecordingService.recordSyntheticMessage(
+        item.role === 'user' ? 'user' : 'gemini',
+        item.parts || [],
+      );
+      return { id, content: item };
+    });
     this.agentHistory.set(wrappedHistory, options);
     this.lastPromptTokenCount = estimateTokenCountSync(
       this.agentHistory.flatMap((c) => c.content.parts || []),
diff --git a/packages/core/src/utils/cryptoUtils.ts b/packages/core/src/utils/cryptoUtils.ts
new file mode 100644
index 0000000000..6c9eff9cde
--- /dev/null
+++ b/packages/core/src/utils/cryptoUtils.ts
@@ -0,0 +1,20 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import { createHash } from 'node:crypto';
+
+/**
+ * Derives a stable, deterministic ID from a list of source IDs.
+ * Used for synthetic turns like summaries to ensure that re-summarizing the same
+ * content produces a consistent identity.
+ */
+export function deriveStableId(sourceIds: string[]): string {
+  const sortedIds = [...sourceIds].sort();
+  return createHash('sha256')
+    .update(sortedIds.join('|'))
+    .digest('hex')
+    .slice(0, 32);
+}
diff --git a/packages/core/src/utils/historyHardening.ts b/packages/core/src/utils/historyHardening.ts
index b635cbcb8f..bb577705d3 100644
--- a/packages/core/src/utils/historyHardening.ts
+++ b/packages/core/src/utils/historyHardening.ts
@@ -7,7 +7,7 @@
 import { type Part } from '@google/genai';
 import { debugLogger } from './debugLogger.js';
 import { type HistoryTurn } from '../core/agentChatHistory.js';
-import { randomUUID } from 'node:crypto';
+import { deriveStableId } from './cryptoUtils.js';
 
 export const SYNTHETIC_THOUGHT_SIGNATURE = 'skip_thought_signature_validator';
 
@@ -153,7 +153,7 @@ function pairToolsAndEnforceSignatures(
             targetUserTurn = nextTurn;
           } else {
             targetUserTurn = {
-              id: randomUUID(),
+              id: deriveStableId([turn.id, 'sentinel_resp']),
               content: { role: 'user', parts: [] },
             };
             work.splice(i + 1, 0, targetUserTurn);
@@ -278,7 +278,7 @@ function enforceRoleConstraints(
       '[HistoryHardener] Final history starts with model role. Prepending sentinel user turn.',
     );
     result.unshift({
-      id: randomUUID(),
+      id: deriveStableId([result[0].id, 'sentinel_start']),
       content: {
         role: 'user',
         parts: [{ text: sentinels.continuation }],
@@ -292,7 +292,7 @@ function enforceRoleConstraints(
       '[HistoryHardener] Final history ends with model role. Appending sentinel user turn.',
     );
     result.push({
-      id: randomUUID(),
+      id: deriveStableId([result[result.length - 1].id, 'sentinel_end']),
       content: {
         role: 'user',
         parts: [{ text: 'Please continue.' }],