diff --git a/CLAUDE.md b/CLAUDE.md
index 02d400e..cb01347 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -70,7 +70,7 @@ Auth uses timing-safe token comparison. Origin allowlisting supports `"*"` wildc
 | `remember_context` | Single write tool for chat and admin clients: save durable memory with optional topic, draft flag or explicit branch state, image input, and artifact refs |
 | `search_context` | Query → embedding → Firestore vector similarity search (cosine, top-K) with metadata filters |
 | `fetch_context` | Retrieve one stored memory by document ID after search |
-| `deprecate_context` | Soft-delete: mark document as deprecated, record superseding document ID |
+| `deprecate_context` | Soft-delete: mark document as deprecated, record superseding document ID, and record supersession_reason ("changed" sets valid_until, "corrected" does not) |
 | `consolidate_context` | Merge N related memories into one canonical active memory via LLM; deprecates all sources with `superseded_by` pointing to the merged result. Defaults to WIP queue for a topic; accepts explicit `source_ids` for targeted consolidation |
 
 ### Key Source Files (all under `functions/src/`)
@@ -95,11 +95,11 @@ Auth uses timing-safe token comparison. Origin allowlisting supports `"*"` wildc
 
 **remember_context**: Chat/admin input → server defaults/inference for metadata and lifecycle state → Gemini multimodal normalization (if image) → canonical `content` + internal `retrieval_text` → Gemini embedding (deployment currently pinned to 768-dim) → Firestore document with vector + metadata
 
-**search_context**: Query text → Gemini embedding → Firestore `findNearest()` (cosine distance, top-K) with required `branch_state` and optional topic filter
+**search_context**: Query text → Gemini embedding → Firestore `findNearest()` (cosine distance, top-K) with required `branch_state` and optional topic filter; optional `valid_at` post-filters results in the service layer by temporal validity window
 
 **fetch_context**: Document ID → direct Firestore read of one stored memory
 
-**deprecate_context**: Document ID + superseding ID → update `branch_state` to "deprecated", set `superseded_by`
+**deprecate_context**: Document ID + superseding ID → update `branch_state` to "deprecated", set `superseded_by`; `supersession_reason` ("changed" default sets `valid_until` to now, "corrected" does not) and optional `initiator` are recorded on the deprecated document
 
 **consolidate_context**: Topic (default WIP queue) or explicit `source_ids` → gather source memories → Gemini merge of N contents into one → store merged result as `active` → deprecate every source with `superseded_by` pointing to the merged ID
 
diff --git a/functions/src/mcpServer.ts b/functions/src/mcpServer.ts
index 7006a7f..c65c647 100644
--- a/functions/src/mcpServer.ts
+++ b/functions/src/mcpServer.ts
@@ -18,6 +18,7 @@ import {
 } from "./service.js";
 import {
   BRANCH_STATES,
+  SUPERSESSION_REASONS,
   type BranchState,
   type McpToolName
 } from "./types.js";
@@ -281,7 +282,11 @@ export function createMetaCortexMcpServer(
             .min(1)
             .max(20)
             .optional()
-            .describe("Max results to return. Defaults to 5.")
+            .describe("Max results to return. Defaults to 5."),
+          valid_at: z
+            .number()
+            .optional()
+            .describe("Optional epoch-ms timestamp. When provided, only returns memories valid at that point in time (valid_from <= valid_at < valid_until, excluding corrected records).")
         }
       },
       async args => {
@@ -293,7 +298,8 @@ export function createMetaCortexMcpServer(
           query_length: args.query.trim().length,
           filter_topic: normalizedFilterTopic,
           filter_state: requestedFilterState,
-          limit: args.limit
+          limit: args.limit,
+          valid_at: args.valid_at
         };
         const result = await observeToolCall(
           "search_context",
@@ -424,13 +430,23 @@ export function createMetaCortexMcpServer(
           superseding_id: z
             .string()
             .min(1)
-            .describe("The id of the new memory that replaces it.")
+            .describe("The id of the new memory that replaces it."),
+          supersession_reason: z
+            .enum(SUPERSESSION_REASONS)
+            .optional()
+            .describe("Why the memory is being superseded. 'changed' (default) means the old fact was true of its era, records valid_until. 'corrected' means the old record was never true, excluded from valid-time results but kept for audit."),
+          initiator: z
+            .enum(["user", "agent"])
+            .optional()
+            .describe("Who initiated this deprecation, for audit purposes.")
         }
       },
       async args => {
         const requestSummary = {
           id: args.id,
-          superseding_id: args.superseding_id
+          superseding_id: args.superseding_id,
+          supersession_reason: args.supersession_reason,
+          initiator: args.initiator
         };
         const result = await observeToolCall(
           "deprecate_context",
@@ -439,7 +455,8 @@ export function createMetaCortexMcpServer(
           record => ({
             id: record.id,
             superseding_id: record.superseding_id,
-            previous_state: record.previous_state
+            previous_state: record.previous_state,
+            supersession_reason: record.supersession_reason
           })
         );
 
diff --git a/functions/src/memoryRepository.ts b/functions/src/memoryRepository.ts
index 3c8b75e..6f84191 100644
--- a/functions/src/memoryRepository.ts
+++ b/functions/src/memoryRepository.ts
@@ -5,7 +5,8 @@ import type {
   BranchState,
   MemoryDocument,
   MemoryMedia,
-  MemoryMetadata
+  MemoryMetadata,
+  SupersessionReason
 } from "./types.js";
 
 export interface StoreMemoryParams {
@@ -28,7 +29,11 @@ export interface MemoryRepository {
   store(params: StoreMemoryParams): Promise<{ document: MemoryDocument; created: boolean }>;
   search(params: SearchMemoryParams): Promise<MemoryDocument[]>;
   get(documentId: string): Promise<MemoryDocument | null>;
-  deprecate(documentId: string, supersedingDocumentId: string): Promise<{ previousState: BranchState }>;
+  deprecate(
+    documentId: string,
+    supersedingDocumentId: string,
+    options?: { supersessionReason?: SupersessionReason; initiator?: "user" | "agent" }
+  ): Promise<{ previousState: BranchState }>;
   getConsolidationQueue(moduleName?: string): Promise<MemoryDocument[]>;
 }
 
@@ -162,7 +167,8 @@ export class FirestoreMemoryRepository implements MemoryRepository {
 
   async deprecate(
     documentId: string,
-    supersedingDocumentId: string
+    supersedingDocumentId: string,
+    options?: { supersessionReason?: SupersessionReason; initiator?: "user" | "agent" }
   ): Promise<{ previousState: BranchState }> {
     const docRef = this.firestore
       .collection(this.collectionName)
@@ -177,11 +183,25 @@ export class FirestoreMemoryRepository implements MemoryRepository {
     const data = snapshot.data() as FirestoreMemoryDocument;
     const previousState = data.metadata.branch_state;
 
-    await docRef.update({
+    const now = Date.now();
+    const resolvedReason = options?.supersessionReason ?? "changed";
+
+    const updates: Record<string, unknown> = {
       "metadata.branch_state": "deprecated",
       "metadata.superseded_by": supersedingDocumentId,
-      "metadata.updated_at": Date.now()
-    });
+      "metadata.updated_at": now,
+      "metadata.supersession_reason": resolvedReason
+    };
+
+    if (resolvedReason === "changed") {
+      updates["metadata.valid_until"] = now;
+    }
+
+    if (options?.initiator) {
+      updates["metadata.initiator"] = options.initiator;
+    }
+
+    await docRef.update(updates);
 
     return { previousState };
   }
diff --git a/functions/src/service.ts b/functions/src/service.ts
index 4622902..5e9bcbd 100644
--- a/functions/src/service.ts
+++ b/functions/src/service.ts
@@ -18,11 +18,13 @@ import type {
   FetchContextInput,
   FetchContextResult,
   MemoryDocument,
+  MemoryMetadata,
   RememberContextInput,
   SearchContextInput,
   SearchContextResult,
   StoreContextInput,
-  StoreContextResult
+  StoreContextResult,
+  SupersessionReason
 } from "./types.js";
 import type { MemoryRepository } from "./memoryRepository.js";
 
@@ -62,6 +64,12 @@ export class MetaCortexService {
       modality: preparedContent.modality,
       ...(normalizedArtifactRefs.length > 0
         ? { artifact_refs: normalizedArtifactRefs }
+        : {}),
+      ...(typeof input.valid_from === "number"
+        ? { valid_from: input.valid_from }
+        : {}),
+      ...(typeof input.valid_until === "number"
+        ? { valid_until: input.valid_until }
         : {})
     } as const;
 
@@ -101,7 +109,9 @@ export class MetaCortexService {
       branch_state: branchState,
       artifact_refs: input.artifact_refs,
       image_base64: normalizeOptionalText(input.image_base64),
-      image_mime_type: normalizeOptionalText(input.image_mime_type)
+      image_mime_type: normalizeOptionalText(input.image_mime_type),
+      valid_from: input.valid_from,
+      valid_until: input.valid_until
     });
   }
 
@@ -113,13 +123,17 @@ export class MetaCortexService {
       text: normalizedQuery,
       taskType: "RETRIEVAL_QUERY"
     });
-    const matches = await this.repository.search({
+    let matches = await this.repository.search({
       queryVector,
       limit: input.limit ?? this.config.topK,
       filterModule: filterTopic,
       filterState
     });
 
+    if (typeof input.valid_at === "number") {
+      matches = matches.filter(match => matchesValidAt(match.metadata, input.valid_at!));
+    }
+
     return {
       matches,
       appliedFilters: {
@@ -141,15 +155,21 @@ export class MetaCortexService {
   }
 
   async deprecateContext(input: DeprecateContextInput): Promise<DeprecateContextResult> {
+    const resolvedReason: SupersessionReason = input.supersession_reason ?? "changed";
     const { previousState } = await this.repository.deprecate(
       input.id,
-      input.superseding_id
+      input.superseding_id,
+      {
+        supersessionReason: resolvedReason,
+        initiator: input.initiator
+      }
     );
 
     return {
       id: input.id,
       superseding_id: input.superseding_id,
-      previous_state: previousState
+      previous_state: previousState,
+      supersession_reason: resolvedReason
     };
   }
 
@@ -300,7 +320,8 @@ export function buildDeprecatePayload(
     item: {
       id: result.id,
       branch_state: "deprecated",
-      superseded_by: result.superseding_id
+      superseded_by: result.superseding_id,
+      supersession_reason: result.supersession_reason
     },
     previous_state: result.previous_state
   };
@@ -406,3 +427,11 @@ function normalizePublicModality(value: string): "text" | "image" | "mixed" {
 
   return "text";
 }
+
+function matchesValidAt(metadata: MemoryMetadata, validAt: number): boolean {
+  const validFromOk = typeof metadata.valid_from === "undefined" || metadata.valid_from <= validAt;
+  const validUntilOk = typeof metadata.valid_until === "undefined" || metadata.valid_until > validAt;
+  const reasonOk = metadata.supersession_reason !== "corrected";
+
+  return validFromOk && validUntilOk && reasonOk;
+}
diff --git a/functions/src/types.ts b/functions/src/types.ts
index 359f0be..03406bc 100644
--- a/functions/src/types.ts
+++ b/functions/src/types.ts
@@ -13,6 +13,8 @@ export const BRANCH_STATES = [
   "wip"
 ] as const;
 
+export const SUPERSESSION_REASONS = ["changed", "corrected"] as const;
+
 export const MEMORY_MODALITIES = [
   "text",
   "image",
@@ -20,6 +22,7 @@ export const MEMORY_MODALITIES = [
 ] as const;
 
 export type BranchState = (typeof BRANCH_STATES)[number];
+export type SupersessionReason = (typeof SUPERSESSION_REASONS)[number];
 export type MemoryModality = (typeof MEMORY_MODALITIES)[number];
 export type McpToolName = (typeof MCP_TOOL_NAMES)[number];
 
@@ -36,6 +39,10 @@ export interface MemoryMetadata {
   modality: MemoryModality;
   artifact_refs?: string[];
   superseded_by?: string;
+  valid_from?: number;
+  valid_until?: number;
+  supersession_reason?: SupersessionReason;
+  initiator?: "user" | "agent";
 }
 
 export interface MemoryDocument {
@@ -54,6 +61,8 @@ export interface StoreContextInput {
   artifact_refs?: string[];
   image_base64?: string;
   image_mime_type?: string;
+  valid_from?: number;
+  valid_until?: number;
 }
 
 export interface SearchContextInput {
@@ -61,6 +70,7 @@ export interface SearchContextInput {
   filter_topic?: string;
   filter_state?: BranchState;
   limit?: number;
+  valid_at?: number;
 }
 
 export interface RememberContextInput {
@@ -71,6 +81,8 @@ export interface RememberContextInput {
   artifact_refs?: string[];
   image_base64?: string;
   image_mime_type?: string;
+  valid_from?: number;
+  valid_until?: number;
 }
 
 export interface StoreContextResult {
@@ -102,12 +114,15 @@ export interface FetchContextResult {
 export interface DeprecateContextInput {
   id: string;
   superseding_id: string;
+  supersession_reason?: SupersessionReason;
+  initiator?: "user" | "agent";
 }
 
 export interface DeprecateContextResult {
   id: string;
   superseding_id: string;
   previous_state: BranchState;
+  supersession_reason: SupersessionReason;
 }
 
 export interface ConsolidationQueueInput {
diff --git a/functions/test/mcp.integration.test.ts b/functions/test/mcp.integration.test.ts
index c863678..64be376 100644
--- a/functions/test/mcp.integration.test.ts
+++ b/functions/test/mcp.integration.test.ts
@@ -218,6 +218,157 @@ describe("MCP integration", () => {
     );
   });
 
+  it("supports temporal validity fields on deprecate_context and search_context", async () => {
+    const runtime = createTestRuntime();
+    const baseUrl = await startServer(
+      createMetaCortexApp({
+        getConfig: () => runtime.config,
+        getObserver: () => runtime.observer,
+        getRuntime: () => runtime
+      }),
+      cleanup
+    );
+
+    const client = new Client({
+      name: "test-client",
+      version: "1.0.0"
+    });
+    const transport = new StreamableHTTPClientTransport(new URL(`${baseUrl}/mcp`), {
+      requestInit: {
+        headers: {
+          [authorizationHeaderName]: bearerHeader("test")
+        }
+      }
+    });
+
+    cleanup.push(async () => {
+      await client.close();
+    });
+
+    await client.connect(transport);
+
+    // Call remember_context to create a memory
+    const rememberResult = await client.callTool({
+      name: "remember_context",
+      arguments: {
+        content: "We are using Ktor for networking.",
+        topic: "kmp-networking"
+      }
+    });
+
+    const rememberPayload = parseJsonTextContent(rememberResult) as any;
+    expect(rememberPayload).toMatchObject({
+      write_status: "created"
+    });
+    const firstId = rememberPayload.item.id;
+
+    // Call remember_context again to create a second "replacement" memory
+    const replacementResult = await client.callTool({
+      name: "remember_context",
+      arguments: {
+        content: "We standardized on Ktor 3 for shared networking.",
+        topic: "kmp-networking"
+      }
+    });
+
+    const replacementPayload = parseJsonTextContent(replacementResult) as any;
+    expect(replacementPayload).toMatchObject({
+      write_status: "created"
+    });
+    const secondId = replacementPayload.item.id;
+
+    // Call deprecate_context with corrected reason and initiator user
+    const deprecateResult = await client.callTool({
+      name: "deprecate_context",
+      arguments: {
+        id: firstId,
+        superseding_id: secondId,
+        supersession_reason: "corrected",
+        initiator: "user"
+      }
+    });
+
+    expect(parseJsonTextContent(deprecateResult)).toMatchObject({
+      item: {
+        id: firstId,
+        branch_state: "deprecated",
+        superseded_by: secondId,
+        supersession_reason: "corrected"
+      },
+      previous_state: "active"
+    });
+
+    // Call search_context with valid_at: Date.now() - firstId must not be in matches
+    const searchResult = await client.callTool({
+      name: "search_context",
+      arguments: {
+        query: "networking",
+        filter_state: "deprecated",
+        valid_at: Date.now()
+      }
+    });
+
+    const searchPayload = parseJsonTextContent(searchResult) as any;
+    expect(searchPayload.matches.map((m: any) => m.id)).not.toContain(firstId);
+
+    // Additionally call remember_context to create a third memory
+    const thirdResult = await client.callTool({
+      name: "remember_context",
+      arguments: {
+        content: "We use Ktor for Android and iOS networking.",
+        topic: "kmp-networking"
+      }
+    });
+
+    const thirdPayload = parseJsonTextContent(thirdResult) as any;
+    expect(thirdPayload).toMatchObject({
+      write_status: "created"
+    });
+    const thirdId = thirdPayload.item.id;
+
+    // Capture beforeDeprecation timestamp
+    const beforeDeprecation = Date.now();
+
+    // Call deprecate_context with supersession_reason "changed" (or omit, but we'll specify "changed" as requested)
+    const deprecateThirdResult = await client.callTool({
+      name: "deprecate_context",
+      arguments: {
+        id: thirdId,
+        superseding_id: secondId,
+        supersession_reason: "changed"
+      }
+    });
+
+    const deprecateThirdPayload = parseJsonTextContent(deprecateThirdResult) as any;
+    expect(deprecateThirdPayload.item.supersession_reason).toBe("changed");
+
+    // Search with valid_at before the deprecation - thirdId IS included
+    const searchBeforeResult = await client.callTool({
+      name: "search_context",
+      arguments: {
+        query: "networking",
+        filter_state: "deprecated",
+        valid_at: beforeDeprecation - 1000
+      }
+    });
+
+    const searchBeforePayload = parseJsonTextContent(searchBeforeResult) as any;
+    expect(searchBeforePayload.matches.map((m: any) => m.id)).toContain(thirdId);
+
+    // Search with valid_at after the deprecation - thirdId is NOT included
+    const searchAfterResult = await client.callTool({
+      name: "search_context",
+      arguments: {
+        query: "networking",
+        filter_state: "deprecated",
+        valid_at: Date.now() + 1000
+      }
+    });
+
+    const searchAfterPayload = parseJsonTextContent(searchAfterResult) as any;
+    expect(searchAfterPayload.matches.map((m: any) => m.id)).not.toContain(thirdId);
+  });
+
   it("enforces tool scoping on client-specific endpoints", async () => {
     const runtime = createTestRuntime({
       clientProfiles: [
diff --git a/functions/test/service.test.ts b/functions/test/service.test.ts
index 451f28b..17e9852 100644
--- a/functions/test/service.test.ts
+++ b/functions/test/service.test.ts
@@ -181,6 +181,157 @@ describe("MetaCortexService", () => {
     expect(result.previous_state).toBe("active");
   });
 
+  it("defaults supersession_reason to changed and sets valid_until on deprecate", async () => {
+    const { service, repository } = createService();
+    const stored = await service.storeContext({
+      content:
+        "We are using Ktor for the Android/iOS networking layer.",
+      module_name: "kmp-networking",
+      branch_state: "active"
+    });
+    const replacement = await service.storeContext({
+      content:
+        "We migrated from Ktor to OkHttp for the Android/iOS networking layer.",
+      module_name: "kmp-networking",
+      branch_state: "active"
+    });
+    const result = await service.deprecateContext({
+      id: stored.id,
+      superseding_id: replacement.id
+    });
+
+    expect(result.supersession_reason).toBe("changed");
+
+    const deprecatedDoc = await repository.get(stored.id);
+    expect(deprecatedDoc).not.toBeNull();
+    expect(typeof deprecatedDoc?.metadata.valid_until).toBe("number");
+  });
+
+  it("does not set valid_until when supersession_reason is corrected", async () => {
+    const { service, repository } = createService();
+    const stored = await service.storeContext({
+      content:
+        "We are using Ktor for the Android/iOS networking layer.",
+      module_name: "kmp-networking",
+      branch_state: "active"
+    });
+    const replacement = await service.storeContext({
+      content:
+        "We migrated from Ktor to OkHttp for the Android/iOS networking layer.",
+      module_name: "kmp-networking",
+      branch_state: "active"
+    });
+    const result = await service.deprecateContext({
+      id: stored.id,
+      superseding_id: replacement.id,
+      supersession_reason: "corrected"
+    });
+
+    expect(result.supersession_reason).toBe("corrected");
+
+    const deprecatedDoc = await repository.get(stored.id);
+    expect(deprecatedDoc).not.toBeNull();
+    expect(deprecatedDoc?.metadata.valid_until).toBeUndefined();
+  });
+
+  it("records initiator on deprecate when provided", async () => {
+    const { service, repository } = createService();
+    const stored = await service.storeContext({
+      content:
+        "We are using Ktor for the Android/iOS networking layer.",
+      module_name: "kmp-networking",
+      branch_state: "active"
+    });
+    const replacement = await service.storeContext({
+      content:
+        "We migrated from Ktor to OkHttp for the Android/iOS networking layer.",
+      module_name: "kmp-networking",
+      branch_state: "active"
+    });
+    await service.deprecateContext({
+      id: stored.id,
+      superseding_id: replacement.id,
+      initiator: "user"
+    });
+
+    const deprecatedDoc = await repository.get(stored.id);
+    expect(deprecatedDoc).not.toBeNull();
+    expect(deprecatedDoc?.metadata.initiator).toBe("user");
+  });
+
+  it("search with valid_at excludes documents outside their valid window", async () => {
+    const { service } = createService();
+    const stored = await service.storeContext({
+      content: "We are using Ktor for networking.",
+      module_name: "kmp-networking",
+      branch_state: "active",
+      valid_from: 1000,
+      valid_until: 2000
+    });
+
+    const inside = await service.searchContext({
+      query: "networking",
+      valid_at: 1500
+    });
+    expect(inside.matches.map(m => m.id)).toContain(stored.id);
+
+    const after = await service.searchContext({
+      query: "networking",
+      valid_at: 2500
+    });
+    expect(after.matches.map(m => m.id)).not.toContain(stored.id);
+
+    const before = await service.searchContext({
+      query: "networking",
+      valid_at: 500
+    });
+    expect(before.matches.map(m => m.id)).not.toContain(stored.id);
+  });
+
+  it("search with valid_at excludes corrected documents", async () => {
+    const { service } = createService();
+    const stored = await service.storeContext({
+      content: "We are using Ktor for networking.",
+      module_name: "kmp-networking",
+      branch_state: "active"
+    });
+    const replacement = await service.storeContext({
+      content: "We migrated to OkHttp.",
+      module_name: "kmp-networking",
+      branch_state: "active"
+    });
+
+    await service.deprecateContext({
+      id: stored.id,
+      superseding_id: replacement.id,
+      supersession_reason: "corrected"
+    });
+
+    const result = await service.searchContext({
+      query: "networking",
+      filter_state: "deprecated",
+      valid_at: 1500
+    });
+
+    expect(result.matches.map(m => m.id)).not.toContain(stored.id);
+  });
+
+  it("search with valid_at includes documents with no temporal fields set", async () => {
+    const { service } = createService();
+    const stored = await service.storeContext({
+      content: "We are using Ktor for networking.",
+      module_name: "kmp-networking",
+      branch_state: "active"
+    });
+
+    const result = await service.searchContext({
+      query: "networking",
+      valid_at: 1500
+    });
+
+    expect(result.matches.map(m => m.id)).toContain(stored.id);
+  });
+
   it("fetches a stored document by id", async () => {
     const { service } = createService();
     const stored = await service.storeContext({
diff --git a/functions/test/support/fakes.ts b/functions/test/support/fakes.ts
index 98878c8..06736a7 100644
--- a/functions/test/support/fakes.ts
+++ b/functions/test/support/fakes.ts
@@ -18,7 +18,8 @@ import type {
   BranchState,
   MemoryDocument,
   MemoryMedia,
-  MemoryMetadata
+  MemoryMetadata,
+  SupersessionReason
 } from "../../src/types.js";
 import { MCP_TOOL_NAMES } from "../../src/types.js";
 import {
@@ -189,7 +190,8 @@ export class InMemoryMemoryRepository implements MemoryRepository {
 
   async deprecate(
     documentId: string,
-    supersedingDocumentId: string
+    supersedingDocumentId: string,
+    options?: { supersessionReason?: SupersessionReason; initiator?: "user" | "agent" }
   ): Promise<{ previousState: BranchState }> {
     const record = this.records.find(r => r.id === documentId);
 
@@ -198,11 +200,17 @@ export class InMemoryMemoryRepository implements MemoryRepository {
     }
 
     const previousState = record.metadata.branch_state;
+    const resolvedReason = options?.supersessionReason ?? "changed";
+    const now = Date.now();
+
     record.metadata = {
       ...record.metadata,
       branch_state: "deprecated",
       superseded_by: supersedingDocumentId,
-      updated_at: Date.now()
+      updated_at: now,
+      supersession_reason: resolvedReason,
+      ...(resolvedReason === "changed" ? { valid_until: now } : {}),
+      ...(options?.initiator ? { initiator: options.initiator } : {})
     };
 
     return { previousState };
diff --git a/metacortexplan.md b/metacortexplan.md
index 2287e87..0cca7c9 100644
--- a/metacortexplan.md
+++ b/metacortexplan.md
@@ -56,7 +56,7 @@ The first hardening release addressed Firestore collection scaling, payload opti
 * **Effort:** Medium.
 
 ### 2. Temporal Validity / Fact Versioning
-* **Status:** Proposed
+* **Status:** Implemented 2026-07-11
 * **Goal:** Enable the agent to distinguish old facts from current ones beyond `branch_state`.
 * **Proposal:** Add optional `valid_from` and `valid_until` fields to stored memories. Search results can filter by temporal validity. Update deprecation to set `valid_until` automatically.
 
@@ -99,7 +99,7 @@ The first hardening release addressed Firestore collection scaling, payload opti
 | MCP native | ❌ | ❌ | ❌ | ❌ | ✅ (thin) | ✅ (full) |
 | Client/tenant scoping | Basic | ❌ | ❌ | ❌ | Basic (Spaces) | ✅ (profiles) |
 | Context tiering | ❌ | ❌ | ❌ | ✅ (L0/L1/L2) | ❌ | 🔜 (proposed) |
-| Temporal validity | ❌ | ❌ | ✅ (bi-temporal) | ❌ | ❌ | 🔜 (proposed) |
+| Temporal validity | ❌ | ❌ | ✅ (bi-temporal) | ❌ | ❌ | ✅ (bi-temporal-lite) |
 | Graph relationships | ✅ (hybrid) | ❌ | ✅ (core) | ❌ | ❌ | ❌ |
 | Auto memory evolution | ✅ | ✅ (self-edit) | ✅ | ✅ | ✅ | ❌ |
 | Serverless-native | ❌ | ❌ | ❌ | ❌ | ✅ (CF Workers) | ✅ (Firebase) |