refactor: migrate thread history from JSONL to ocas variable store (Phase 4c)

packages/cli-workflow/src/__tests__/current-role.test.ts

@@ -7,7 +7,7 @@ import type { CasRef, ThreadId } from "@united-workforce/protocol";
 import { createMarker, deleteMarker } from "../background/index.js";
 import { cmdThreadList, cmdThreadShow, cmdThreadStart } from "../commands/thread.js";
 import {
-  appendThreadHistory,
+  addHistoryEntry,
   createUwfStore,
   deleteThread,
   loadAllThreads,
@@ -288,7 +288,7 @@ describe("currentRole field", () => {
       const uwfForIndex = await createUwfStore(storageRoot);
       const head = loadAllThreads(uwfForIndex.varStore)[tid]!.head;
       deleteThread(uwfForIndex.varStore, tid);
-      await appendThreadHistory(storageRoot, {
+      addHistoryEntry(uwfForIndex.varStore, {
         thread: tid,
         workflow,
         head,
@@ -316,7 +316,7 @@ describe("currentRole field", () => {
       const uwfForIndex = await createUwfStore(storageRoot);
       const head = loadAllThreads(uwfForIndex.varStore)[tid]!.head;
       deleteThread(uwfForIndex.varStore, tid);
-      await appendThreadHistory(storageRoot, {
+      addHistoryEntry(uwfForIndex.varStore, {
         thread: tid,
         workflow,
         head,
@@ -377,7 +377,7 @@ describe("currentRole field", () => {
       const uwfForIndex = await createUwfStore(storageRoot);
       const compHead = loadAllThreads(uwfForIndex.varStore)[compId]!.head;
       deleteThread(uwfForIndex.varStore, compId);
-      await appendThreadHistory(storageRoot, {
+      addHistoryEntry(uwfForIndex.varStore, {
         thread: compId,
         workflow: comp.workflow,
         head: compHead,

packages/cli-workflow/src/__tests__/resolve-head-hash.test.ts

@@ -1,15 +1,18 @@
 import { afterEach, beforeEach, describe, expect, test } from "bun:test";
-import { mkdtemp, rm } from "node:fs/promises";
+import { mkdir, mkdtemp, rm } from "node:fs/promises";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
 import { type CasRef, createThreadIndexEntry, type ThreadId } from "@united-workforce/protocol";
 import { resolveHeadHash } from "../commands/shared.js";
-import { appendThreadHistory } from "../store.js";
+import { addHistoryEntry, createUwfStore, setThread } from "../store.js";
 
 let tmpDir: string;
 
 beforeEach(async () => {
   tmpDir = await mkdtemp(join(tmpdir(), "cli-uwf-resolve-head-"));
+  const casDir = join(tmpDir, "cas");
+  await mkdir(casDir, { recursive: true });
+  process.env.UNCAGED_CAS_DIR = casDir;
 });
 
 afterEach(async () => {
@@ -19,7 +22,6 @@ afterEach(async () => {
 describe("resolveHeadHash", () => {
   test("returns head hash from variable store for active thread", async () => {
     const threadId = "01JTEST0000000000000000001" as ThreadId;
-    const { createUwfStore, setThread } = await import("../store.js");
     const uwf = await createUwfStore(tmpDir);
     const headHash = (await uwf.store.put(uwf.schemas.text, "active")) as CasRef;
     setThread(uwf.varStore, threadId, createThreadIndexEntry(headHash as CasRef));
@@ -29,13 +31,13 @@ describe("resolveHeadHash", () => {
     expect(result).toBe(headHash);
   });
 
-  test("falls back to history.jsonl when thread not in threads.yaml", async () => {
+  test("falls back to history variable when thread not in active index", async () => {
     const threadId = "01JTEST0000000000000000002" as ThreadId;
-    const headHash = "completed_hash_456" as CasRef;
     const workflowHash = "workflow_hash_789" as CasRef;
 
-    // No entry in threads.yaml, only in history.jsonl
+    const uwf = await createUwfStore(tmpDir);
-    await appendThreadHistory(tmpDir, {
+    const headHash = (await uwf.store.put(uwf.schemas.text, "completed-head")) as CasRef;
+    addHistoryEntry(uwf.varStore, {
       thread: threadId,
       workflow: workflowHash,
       head: headHash,
@@ -54,15 +56,13 @@ describe("resolveHeadHash", () => {
 
   test("prioritizes active thread over history when thread exists in both", async () => {
     const threadId = "01JTEST0000000000000000004" as ThreadId;
-    const historicalHash = "historical_hash_v1" as CasRef;
     const workflowHash = "workflow_hash_xyz" as CasRef;
 
-    const { createUwfStore, setThread } = await import("../store.js");
-    const { createThreadIndexEntry } = await import("@united-workforce/protocol");
     const uwf = await createUwfStore(tmpDir);
     const activeHead = (await uwf.store.put(uwf.schemas.text, "active-v2")) as CasRef;
+    const historicalHash = (await uwf.store.put(uwf.schemas.text, "historical-v1")) as CasRef;
     setThread(uwf.varStore, threadId, createThreadIndexEntry(activeHead));
-    await appendThreadHistory(tmpDir, {
+    addHistoryEntry(uwf.varStore, {
       thread: threadId,
       workflow: workflowHash,
       head: historicalHash,
@@ -80,25 +80,26 @@ describe("resolveHeadHash", () => {
     const threadId1 = "01JTEST0000000000000000005" as ThreadId;
     const threadId2 = "01JTEST0000000000000000006" as ThreadId;
     const threadId3 = "01JTEST0000000000000000007" as ThreadId;
-    const hash1 = "hash_thread1" as CasRef;
-    const hash2 = "hash_thread2" as CasRef;
-    const hash3 = "hash_thread3" as CasRef;
     const workflowHash = "workflow_hash_abc" as CasRef;
-    await appendThreadHistory(tmpDir, {
+    const uwf = await createUwfStore(tmpDir);
+    const hash1 = (await uwf.store.put(uwf.schemas.text, "hash-thread1")) as CasRef;
+    const hash2 = (await uwf.store.put(uwf.schemas.text, "hash-thread2")) as CasRef;
+    const hash3 = (await uwf.store.put(uwf.schemas.text, "hash-thread3")) as CasRef;
+    addHistoryEntry(uwf.varStore, {
       thread: threadId1,
       workflow: workflowHash,
       head: hash1,
       completedAt: Date.now() - 2000,
       reason: null,
     });
-    await appendThreadHistory(tmpDir, {
+    addHistoryEntry(uwf.varStore, {
       thread: threadId2,
       workflow: workflowHash,
       head: hash2,
       completedAt: Date.now() - 1000,
       reason: null,
     });
-    await appendThreadHistory(tmpDir, {
+    addHistoryEntry(uwf.varStore, {
       thread: threadId3,
       workflow: workflowHash,
       head: hash3,

packages/cli-workflow/src/__tests__/store-global-cas.test.ts

@@ -238,35 +238,78 @@ describe("Global CAS directory", () => {
     await expect(readFile(threadsPath, "utf8")).rejects.toThrow();
   });
 
-  test("history remains in storageRoot", async () => {
+  test("history is stored in global CAS variable store", async () => {
     const globalCasDir = join(tmpDir, "global-cas");
     process.env.UNCAGED_CAS_DIR = globalCasDir;
 
     const storageRoot = join(tmpDir, "storage");
     await mkdir(storageRoot, { recursive: true });
 
-    await createUwfStore(storageRoot);
+    const uwf = await createUwfStore(storageRoot);
-
+    const threadId = "thread-123" as ThreadId;
-    // Write history
+    const headHash = await uwf.store.put(uwf.schemas.text, "history-head");
-    const { appendThreadHistory } = await import("../store.js");
+    const { addHistoryEntry, findHistoryEntry } = await import("../store.js");
-    await appendThreadHistory(storageRoot, {
+    addHistoryEntry(uwf.varStore, {
-      thread: "thread-123" as any,
+      thread: threadId,
       workflow: "workflow-456",
-      head: "hash-789",
+      head: headHash,
       completedAt: Date.now(),
       reason: "completed",
     });
 
-    // Verify history.jsonl is in storageRoot, not global CAS
+    const entry = findHistoryEntry(uwf.varStore, threadId);
-    const { readFile } = await import("node:fs/promises");
+    expect(entry?.thread).toBe(threadId);
-    const historyPath = join(storageRoot, "history.jsonl");
+    expect(entry?.workflow).toBe("workflow-456");
-    const content = await readFile(historyPath, "utf8");
+    expect(entry?.head).toBe(headHash);
-    expect(content).toContain("thread-123");
-    expect(content).toContain("workflow-456");
 
-    // Verify history.jsonl is NOT in global CAS directory
+    const { access } = await import("node:fs/promises");
-    const globalHistoryPath = join(globalCasDir, "history.jsonl");
+    await access(join(globalCasDir, "variables.db"));
-    await expect(readFile(globalHistoryPath, "utf8")).rejects.toThrow();
+
+    const historyPath = join(storageRoot, "history.jsonl");
+    await expect(access(historyPath)).rejects.toThrow();
+  });
+
+  test("migrates history.jsonl to variable store and renames file", async () => {
+    const globalCasDir = join(tmpDir, "global-cas-history");
+    process.env.UNCAGED_CAS_DIR = globalCasDir;
+
+    const storageRoot = join(tmpDir, "storage-history-migrate");
+    await mkdir(storageRoot, { recursive: true });
+
+    const threadId = "01JTEST0000000000000000CD" as ThreadId;
+    const uwfSeed = await createUwfStore(storageRoot);
+    const workflowHash = await uwfSeed.store.put(uwfSeed.schemas.text, "migrated-workflow");
+    const headHash = await uwfSeed.store.put(uwfSeed.schemas.text, "migrated-head");
+    const completedAt = 1780410000000;
+    const { writeFile, access, readFile } = await import("node:fs/promises");
+    const historyPath = join(storageRoot, "history.jsonl");
+    await writeFile(
+      historyPath,
+      `${JSON.stringify({
+        thread: threadId,
+        workflow: workflowHash,
+        head: headHash,
+        completedAt,
+        reason: "cancelled",
+      })}\n`,
+      "utf8",
+    );
+
+    const uwf = await createUwfStore(storageRoot);
+    const { findHistoryEntry } = await import("../store.js");
+    const entry = findHistoryEntry(uwf.varStore, threadId);
+    expect(entry).toEqual({
+      thread: threadId,
+      workflow: workflowHash,
+      head: headHash,
+      completedAt,
+      reason: "cancelled",
+    });
+
+    await expect(access(historyPath)).rejects.toThrow();
+    const migratedContent = await readFile(`${historyPath}.migrated`, "utf8");
+    expect(migratedContent).toContain(threadId);
+    expect(migratedContent).toContain(workflowHash);
   });
 
   test("CAS nodes are stored in global directory", async () => {

packages/cli-workflow/src/__tests__/thread-cancel-status.test.ts

@@ -1,24 +1,40 @@
 import { describe, expect, test } from "bun:test";
-import { mkdtemp } from "node:fs/promises";
+import { mkdir, mkdtemp } from "node:fs/promises";
 import { tmpdir } from "node:os";
 import { join } from "node:path";
 import type { CasRef, ThreadId } from "@united-workforce/protocol";
-import { appendThreadHistory, loadThreadHistory } from "../store.js";
+import { addHistoryEntry, createUwfStore, loadAllHistory } from "../store.js";
+
+async function makeUwfStore(storageRoot: string) {
+  const casDir = join(storageRoot, "cas");
+  await mkdir(casDir, { recursive: true });
+  process.env.UNCAGED_CAS_DIR = casDir;
+  return createUwfStore(storageRoot);
+}
+
+async function seedHistoryHead(
+  uwf: Awaited<ReturnType<typeof createUwfStore>>,
+  label: string,
+): Promise<CasRef> {
+  return (await uwf.store.put(uwf.schemas.text, label)) as CasRef;
+}
 
 describe("thread cancel status", () => {
   test("cancelled history entry has reason 'cancelled'", async () => {
     const tmpDir = await mkdtemp(join(tmpdir(), "uwf-cancel-test-"));
     const threadId = "01JTEST000000000000CANCEL1" as ThreadId;
+    const uwf = await makeUwfStore(tmpDir);
+    const head = await seedHistoryHead(uwf, "cancelled-head");
 
-    await appendThreadHistory(tmpDir, {
+    addHistoryEntry(uwf.varStore, {
       thread: threadId,
       workflow: "test-workflow",
-      head: "test-head-hash" as CasRef,
+      head,
       completedAt: Date.now(),
       reason: "cancelled",
     });
 
-    const history = await loadThreadHistory(tmpDir);
+    const history = loadAllHistory(uwf.varStore);
     expect(history).toHaveLength(1);
     expect(history[0]?.reason).toBe("cancelled");
   });
@@ -26,60 +42,66 @@ describe("thread cancel status", () => {
   test("completed history entry has reason 'completed'", async () => {
     const tmpDir = await mkdtemp(join(tmpdir(), "uwf-cancel-test-"));
     const threadId = "01JTEST000000000000CANCEL2" as ThreadId;
+    const uwf = await makeUwfStore(tmpDir);
+    const head = await seedHistoryHead(uwf, "completed-head");
 
-    await appendThreadHistory(tmpDir, {
+    addHistoryEntry(uwf.varStore, {
       thread: threadId,
       workflow: "test-workflow",
-      head: "test-head-hash" as CasRef,
+      head,
       completedAt: Date.now(),
       reason: "completed",
     });
 
-    const history = await loadThreadHistory(tmpDir);
+    const history = loadAllHistory(uwf.varStore);
     expect(history).toHaveLength(1);
     expect(history[0]?.reason).toBe("completed");
   });
 
-  test("legacy history entry without reason parses as null", async () => {
+  test("history entry with null reason is stored as completed", async () => {
     const tmpDir = await mkdtemp(join(tmpdir(), "uwf-cancel-test-"));
     const threadId = "01JTEST000000000000CANCEL3" as ThreadId;
+    const uwf = await makeUwfStore(tmpDir);
+    const head = await seedHistoryHead(uwf, "legacy-head");
 
-    // Simulate legacy entry without reason field
+    addHistoryEntry(uwf.varStore, {
-    await appendThreadHistory(tmpDir, {
       thread: threadId,
       workflow: "test-workflow",
-      head: "test-head-hash" as CasRef,
+      head,
       completedAt: Date.now(),
       reason: null,
     });
 
-    const history = await loadThreadHistory(tmpDir);
+    const history = loadAllHistory(uwf.varStore);
     expect(history).toHaveLength(1);
-    expect(history[0]?.reason).toBeNull();
+    expect(history[0]?.reason).toBe("completed");
   });
 
   test("mixed completed and cancelled entries preserve distinct reasons", async () => {
     const tmpDir = await mkdtemp(join(tmpdir(), "uwf-cancel-test-"));
+    const uwf = await makeUwfStore(tmpDir);
+    const head1 = await seedHistoryHead(uwf, "head1");
+    const head2 = await seedHistoryHead(uwf, "head2");
 
-    await appendThreadHistory(tmpDir, {
+    addHistoryEntry(uwf.varStore, {
       thread: "01JTEST000000000000CANCEL4" as ThreadId,
       workflow: "test-workflow",
-      head: "head1" as CasRef,
+      head: head1,
       completedAt: Date.now(),
       reason: "completed",
     });
 
-    await appendThreadHistory(tmpDir, {
+    addHistoryEntry(uwf.varStore, {
       thread: "01JTEST000000000000CANCEL5" as ThreadId,
       workflow: "test-workflow",
-      head: "head2" as CasRef,
+      head: head2,
       completedAt: Date.now(),
       reason: "cancelled",
     });
 
-    const history = await loadThreadHistory(tmpDir);
+    const history = loadAllHistory(uwf.varStore);
     expect(history).toHaveLength(2);
-    expect(history[0]?.reason).toBe("completed");
+    const reasons = history.map((entry) => entry.reason).sort();
-    expect(history[1]?.reason).toBe("cancelled");
+    expect(reasons).toEqual(["cancelled", "completed"]);
   });
 });

packages/cli-workflow/src/__tests__/thread-list-filters.test.ts

@@ -10,7 +10,7 @@ import { cmdThreadList } from "../commands/thread.js";
 import { parseTimeInput } from "../commands/thread-time-parser.js";
 import type { UwfStore } from "../store.js";
 import {
-  appendThreadHistory,
+  addHistoryEntry,
   createUwfStore,
   deleteThread,
   loadAllThreads,
@@ -78,7 +78,7 @@ async function completeThread(
 ) {
   const uwfIdx = await createUwfStore(storageRoot);
   deleteThread(uwfIdx.varStore, threadId);
-  await appendThreadHistory(storageRoot, {
+  addHistoryEntry(uwfIdx.varStore, {
     thread: threadId,
     workflow: workflowHash,
     head: headHash,

packages/cli-workflow/src/__tests__/thread-show-status.test.ts

@@ -7,7 +7,7 @@ import type { CasRef, ThreadId } from "@united-workforce/protocol";
 import { createMarker, deleteMarker } from "../background/index.js";
 import { cmdThreadShow, cmdThreadStart } from "../commands/thread.js";
 import {
-  appendThreadHistory,
+  addHistoryEntry,
   createUwfStore,
   deleteThread,
   loadAllThreads,
@@ -210,7 +210,7 @@ describe("thread show status field", () => {
 
     deleteThread(uwfForIndex.varStore, threadId);
 
-    await appendThreadHistory(storageRoot, {
+    addHistoryEntry(uwfForIndex.varStore, {
       thread: threadId,
       workflow,
       head,
@@ -247,7 +247,7 @@ describe("thread show status field", () => {
 
     deleteThread(uwfForIndex.varStore, threadId);
 
-    await appendThreadHistory(storageRoot, {
+    addHistoryEntry(uwfForIndex.varStore, {
       thread: threadId,
       workflow,
       head,
@@ -284,7 +284,7 @@ describe("thread show status field", () => {
 
     deleteThread(uwfForIndex.varStore, threadId);
 
-    await appendThreadHistory(storageRoot, {
+    addHistoryEntry(uwfForIndex.varStore, {
       thread: threadId,
       workflow,
       head,

packages/cli-workflow/src/__tests__/thread.test.ts

@@ -12,7 +12,7 @@ import {
   THREAD_READ_DEFAULT_QUOTA,
 } from "../commands/thread.js";
 import type { UwfStore } from "../store.js";
-import { appendThreadHistory, createUwfStore } from "../store.js";
+import { addHistoryEntry, createUwfStore } from "../store.js";
 import { seedThreads } from "./thread-test-helpers.js";
 
 // ── schemas used in tests ────────────────────────────────────────────────────
@@ -744,9 +744,9 @@ describe("cmdStepList with completed threads", () => {
     });
 
     const threadId = "01JTEST0000000000000000A2" as ThreadId;
-    // Thread is NOT in threads.yaml (simulating completed thread)
+    // Thread is NOT in active index (simulating completed thread)
-    // But it IS in history.jsonl
+    // But it IS in history variable store
-    await appendThreadHistory(tmpDir, {
+    addHistoryEntry(uwf.varStore, {
       thread: threadId,
       workflow: workflowHash,
       head: step2Hash,
@@ -872,9 +872,9 @@ describe("cmdStepShow with completed threads", () => {
     });
 
     const threadId = "01JTEST0000000000000000B2" as ThreadId;
-    // Thread is NOT in threads.yaml
+    // Thread is NOT in active index
-    // But it IS in history.jsonl
+    // But it IS in history variable store
-    await appendThreadHistory(tmpDir, {
+    addHistoryEntry(uwf.varStore, {
       thread: threadId,
       workflow: workflowHash,
       head: stepHash,
@@ -935,9 +935,9 @@ describe("cmdThreadRead with completed threads", () => {
     });
 
     const threadId = "01JTEST0000000000000000C1" as ThreadId;
-    // Thread is NOT in threads.yaml
+    // Thread is NOT in active index
-    // But it IS in history.jsonl
+    // But it IS in history variable store
-    await appendThreadHistory(tmpDir, {
+    addHistoryEntry(uwf.varStore, {
       thread: threadId,
       workflow: workflowHash,
       head: stepHash,
@@ -999,7 +999,7 @@ describe("cmdThreadRead with completed threads", () => {
     });
 
     const threadId = "01JTEST0000000000000000C2" as ThreadId;
-    await appendThreadHistory(tmpDir, {
+    addHistoryEntry(uwf.varStore, {
       thread: threadId,
       workflow: workflowHash,
       head: step3Hash,

packages/cli-workflow/src/commands/shared.ts

@@ -6,7 +6,7 @@ import type {
   StepNodePayload,
   ThreadId,
 } from "@united-workforce/protocol";
-import { createUwfStore, findThreadInHistory, getThread, type UwfStore } from "../store.js";
+import { createUwfStore, findHistoryEntry, getThread, type UwfStore } from "../store.js";
 
 type ChainState = {
   startHash: CasRef;
@@ -207,7 +207,7 @@ async function resolveHeadHash(storageRoot: string, threadId: ThreadId): Promise
   if (entry !== null) {
     return entry.head;
   }
-  const hist = await findThreadInHistory(storageRoot, threadId);
+  const hist = findHistoryEntry(uwf.varStore, threadId);
   if (hist !== null) {
     return hist.head;
   }

packages/cli-workflow/src/commands/thread.ts

@@ -38,13 +38,13 @@ import { createMarker, deleteMarker, isThreadRunning } from "../background/index
 import { createIncludeTag } from "../include.js";
 import { evaluate, isSuspendResult } from "../moderator/index.js";
 import {
-  appendThreadHistory,
+  addHistoryEntry,
   createUwfStore,
   deleteThread,
-  findThreadInHistory,
+  findHistoryEntry,
   getThread,
+  loadAllHistory,
   loadAllThreads,
-  loadThreadHistory,
   loadWorkflowRegistry,
   resolveWorkflowHash,
   setThread,
@@ -521,7 +521,7 @@ export async function cmdThreadShow(
     };
   }
 
-  const hist = await findThreadInHistory(storageRoot, threadId);
+  const hist = findHistoryEntry(uwf.varStore, threadId);
   if (hist !== null) {
     const status: ThreadStatus = hist.reason === "cancelled" ? "cancelled" : "completed";
 
@@ -593,12 +593,12 @@ async function collectActiveThreads(
   return items;
 }
 
-async function collectCompletedThreads(
+function collectCompletedThreads(
-  storageRoot: string,
+  varStore: VariableStore,
   activeIds: Set<ThreadId>,
-): Promise<ThreadListItemWithStatus[]> {
+): ThreadListItemWithStatus[] {
   const items: ThreadListItemWithStatus[] = [];
-  const history = await loadThreadHistory(storageRoot);
+  const history = loadAllHistory(varStore);
   const seen = new Set<ThreadId>(); // Deduplication (issue #470)
   for (const entry of history) {
     if (!activeIds.has(entry.thread) && !seen.has(entry.thread)) {
@@ -671,7 +671,7 @@ export async function cmdThreadList(
     statusFilter.includes("cancelled");
   if (includeCompleted) {
     const activeIds = new Set(items.map((i) => i.thread));
-    const completedItems = await collectCompletedThreads(storageRoot, activeIds);
+    const completedItems = collectCompletedThreads(uwf.varStore, activeIds);
     items = items.concat(completedItems);
   }
 
@@ -1035,15 +1035,9 @@ function spawnAgent(
   return obj as unknown as AdapterOutput;
 }
 
-async function archiveThread(
+function archiveThread(uwf: UwfStore, threadId: ThreadId, workflow: CasRef, head: CasRef): void {
-  uwf: UwfStore,
-  storageRoot: string,
-  threadId: ThreadId,
-  workflow: CasRef,
-  head: CasRef,
-): Promise<void> {
   deleteThread(uwf.varStore, threadId);
-  await appendThreadHistory(storageRoot, {
+  addHistoryEntry(uwf.varStore, {
     thread: threadId,
     workflow,
     head,
@@ -1302,7 +1296,7 @@ async function resolveModeratorStepTarget(
 
   if (nextResult.value.role === END_ROLE) {
     plog.log(PL_THREAD_ARCHIVED, `thread archived head=${headHash}`, null);
-    await archiveThread(uwf, storageRoot, threadId, workflowHash, headHash);
+    archiveThread(uwf, threadId, workflowHash, headHash);
     return {
       workflow: workflowHash,
       thread: threadId,
@@ -1368,7 +1362,7 @@ async function finalizeAgentStep(
   const done = afterResult.value.role === END_ROLE;
   if (done) {
     plog.log(PL_THREAD_ARCHIVED, `thread archived head=${newHead}`, null);
-    await archiveThread(uwfAfter, storageRoot, threadId, workflowHash, newHead);
+    archiveThread(uwfAfter, threadId, workflowHash, newHead);
   }
 
   const status: ThreadStatus = done ? "completed" : "idle";
@@ -1456,7 +1450,7 @@ async function resolveHeadHash(storageRoot: string, threadId: ThreadId): Promise
   if (entry !== null) {
     return entry.head;
   }
-  const hist = await findThreadInHistory(storageRoot, threadId);
+  const hist = findHistoryEntry(uwf.varStore, threadId);
   if (hist !== null) {
     return hist.head;
   }
@@ -1566,7 +1560,7 @@ export async function cmdThreadCancel(
     completedAt: Date.now(),
     reason: "cancelled",
   };
-  await appendThreadHistory(storageRoot, historyEntry);
+  addHistoryEntry(uwf.varStore, historyEntry);
 
   return { thread: threadId, cancelled: true };
 }

packages/cli-workflow/src/store.ts

@@ -1,6 +1,6 @@
 import type { Dirent } from "node:fs";
 import { existsSync, symlinkSync } from "node:fs";
-import { access, appendFile, mkdir, readdir, readFile, rename } from "node:fs/promises";
+import { access, mkdir, readdir, readFile, rename } from "node:fs/promises";
 import { homedir } from "node:os";
 import { join } from "node:path";
 
@@ -27,6 +27,9 @@ export const REGISTRY_VAR_PREFIX = "@uwf/registry/";
 /** Variable name prefix for active thread entries (`@uwf/thread/<thread-id>`). */
 export const THREAD_VAR_PREFIX = "@uwf/thread/";
 
+/** Variable name prefix for completed/cancelled thread history (`@uwf/history/<thread-id>`). */
+export const HISTORY_VAR_PREFIX = "@uwf/history/";
+
 /** A workflow entry discovered from the project-local .workflows/ directory. */
 export type ProjectWorkflowEntry = {
   /** Workflow name (from YAML `name` field, equals filename stem). */
@@ -190,10 +193,6 @@ export function getThreadsPath(storageRoot: string): string {
   return join(storageRoot, "threads.yaml");
 }
 
-export function getHistoryPath(storageRoot: string): string {
-  return join(storageRoot, "history.jsonl");
-}
-
 export type ThreadHistoryLine = ThreadListItem & {
   completedAt: number;
   reason: "completed" | "cancelled" | null;
@@ -214,6 +213,7 @@ export async function createUwfStore(storageRoot: string): Promise<UwfStore> {
   const varStore = createVariableStore(join(casDir, "variables.db"), store);
   await migrateWorkflowRegistryIfNeeded(storageRoot, varStore);
   await migrateThreadsIndexIfNeeded(storageRoot, varStore);
+  await migrateHistoryIfNeeded(storageRoot, varStore);
   return { storageRoot, store, schemas, varStore };
 }
 
@@ -384,24 +384,15 @@ export function deleteThread(varStore: VariableStore, threadId: ThreadId): void
   varStore.remove(threadVarName(threadId));
 }
 
-export async function loadThreadHistory(storageRoot: string): Promise<ThreadHistoryLine[]> {
+function parseHistoryJsonlLine(trimmed: string): ThreadHistoryLine | null {
-  const path = getHistoryPath(storageRoot);
-  try {
-    const text = await readFile(path, "utf8");
-    const lines: ThreadHistoryLine[] = [];
-    for (const line of text.split("\n")) {
-      const trimmed = line.trim();
-      if (trimmed === "") {
-        continue;
-      }
   let raw: unknown;
   try {
     raw = JSON.parse(trimmed) as unknown;
   } catch {
-        continue;
+    return null;
   }
   if (raw === null || typeof raw !== "object" || Array.isArray(raw)) {
-        continue;
+    return null;
   }
   const rec = raw as Record<string, unknown>;
   const thread = rec.thread;
@@ -416,45 +407,77 @@ export async function loadThreadHistory(storageRoot: string): Promise<ThreadHist
   ) {
     const reason = rec.reason;
     const parsedReason = reason === "completed" || reason === "cancelled" ? reason : null;
-        lines.push({
+    return {
       thread: thread as ThreadId,
       workflow,
       head,
       completedAt,
       reason: parsedReason,
-        });
+    };
-      }
-    }
-    return lines;
-  } catch (e) {
-    const err = e as NodeJS.ErrnoException;
-    if (err.code === "ENOENT") {
-      return [];
-    }
-    throw e;
-  }
-}
-
-export async function findThreadInHistory(
-  storageRoot: string,
-  threadId: ThreadId,
-): Promise<ThreadHistoryLine | null> {
-  const history = await loadThreadHistory(storageRoot);
-  for (let i = history.length - 1; i >= 0; i--) {
-    const entry = history[i];
-    if (entry !== undefined && entry.thread === threadId) {
-      return entry;
-    }
   }
   return null;
 }
 
-export async function appendThreadHistory(
+/** One-time migration: `~/.uwf/history.jsonl` → `@uwf/history/*` variables. */
+export async function migrateHistoryIfNeeded(
   storageRoot: string,
-  entry: ThreadHistoryLine,
+  varStore: VariableStore,
 ): Promise<void> {
-  const path = getHistoryPath(storageRoot);
+  const path = join(storageRoot, "history.jsonl");
-  await mkdir(storageRoot, { recursive: true });
+  if (!existsSync(path)) {
-  const line = `${JSON.stringify(entry)}\n`;
+    return;
-  await appendFile(path, line, "utf8");
+  }
+
+  const text = await readFile(path, "utf8");
+  for (const line of text.split("\n")) {
+    const trimmed = line.trim();
+    if (trimmed === "") {
+      continue;
+    }
+    const entry = parseHistoryJsonlLine(trimmed);
+    if (entry !== null) {
+      addHistoryEntry(varStore, entry);
+    }
+  }
+
+  await rename(path, `${path}.migrated`);
+}
+
+export function loadAllHistory(varStore: VariableStore): ThreadHistoryLine[] {
+  const vars = varStore.list({ namePrefix: HISTORY_VAR_PREFIX });
+  return vars.map((v) => ({
+    thread: v.name.slice(HISTORY_VAR_PREFIX.length) as ThreadId,
+    workflow: v.tags.workflow ?? "",
+    head: v.value as CasRef,
+    completedAt: Number(v.tags.completedAt ?? "0"),
+    reason: v.tags.reason === "completed" || v.tags.reason === "cancelled" ? v.tags.reason : null,
+  }));
+}
+
+export function findHistoryEntry(
+  varStore: VariableStore,
+  threadId: ThreadId,
+): ThreadHistoryLine | null {
+  const vars = varStore.list({ namePrefix: `${HISTORY_VAR_PREFIX}${threadId}` });
+  const v = vars.find((entry) => entry.name === `${HISTORY_VAR_PREFIX}${threadId}`);
+  if (v === undefined) {
+    return null;
+  }
+  return {
+    thread: threadId,
+    workflow: v.tags.workflow ?? "",
+    head: v.value as CasRef,
+    completedAt: Number(v.tags.completedAt ?? "0"),
+    reason: v.tags.reason === "completed" || v.tags.reason === "cancelled" ? v.tags.reason : null,
+  };
+}
+
+export function addHistoryEntry(varStore: VariableStore, entry: ThreadHistoryLine): void {
+  varStore.set(`${HISTORY_VAR_PREFIX}${entry.thread}`, entry.head, {
+    tags: {
+      workflow: entry.workflow,
+      completedAt: String(entry.completedAt),
+      reason: entry.reason ?? "completed",
+    },
+  });
 }