Memory/QMD: skip unchanged session export writes

CHANGELOG.md

@@ -72,6 +72,7 @@ Docs: https://docs.openclaw.ai
 - Memory/QMD: make QMD result JSON parsing resilient to noisy command output by extracting the first JSON array from noisy `stdout`.
 - Memory/QMD: pass result limits to `search`/`vsearch` commands so QMD can cap results earlier.
 - Memory/QMD: avoid reading full markdown files when a `from/lines` window is requested in QMD reads.
+- Memory/QMD: skip rewriting unchanged session export markdown files during sync to reduce disk churn.
 - Models/CLI: guard `models status` string trimming paths to prevent crashes from malformed non-string config values. (#16395) Thanks @BinHPdev.
 
 ## 2026.2.14

src/memory/qmd-manager.test.ts

@@ -809,6 +809,58 @@ describe("QmdMemoryManager", () => {
     readFileSpy.mockRestore();
   });
 
+  it("reuses exported session markdown files when inputs are unchanged", async () => {
+    const writeFileSpy = vi.spyOn(fs, "writeFile");
+    const sessionsDir = path.join(stateDir, "agents", agentId, "sessions");
+    await fs.mkdir(sessionsDir, { recursive: true });
+    const sessionFile = path.join(sessionsDir, "session-1.jsonl");
+    await fs.writeFile(
+      sessionFile,
+      '{"type":"message","message":{"role":"user","content":"hello"}}\n',
+      "utf-8",
+    );
+
+    cfg = {
+      ...cfg,
+      memory: {
+        ...cfg.memory,
+        qmd: {
+          ...cfg.memory.qmd,
+          sessions: {
+            enabled: true,
+          },
+        },
+      },
+    } as OpenClawConfig;
+
+    const resolved = resolveMemoryBackendConfig({ cfg, agentId });
+    const manager = await QmdMemoryManager.create({ cfg, agentId, resolved });
+    expect(manager).toBeTruthy();
+    if (!manager) {
+      throw new Error("manager missing");
+    }
+
+    const reasonCount = writeFileSpy.mock.calls.length;
+    await manager.sync({ reason: "manual" });
+    const firstExportWrites = writeFileSpy.mock.calls.length;
+    expect(firstExportWrites).toBe(reasonCount + 1);
+
+    await manager.sync({ reason: "manual" });
+    expect(writeFileSpy.mock.calls.length).toBe(firstExportWrites);
+
+    await new Promise((resolve) => setTimeout(resolve, 5));
+    await fs.writeFile(
+      sessionFile,
+      '{"type":"message","message":{"role":"user","content":"follow-up update"}}\n',
+      "utf-8",
+    );
+    await manager.sync({ reason: "manual" });
+    expect(writeFileSpy.mock.calls.length).toBe(firstExportWrites + 1);
+
+    await manager.close();
+    writeFileSpy.mockRestore();
+  });
+
   it("throws when sqlite index is busy", async () => {
     const resolved = resolveMemoryBackendConfig({ cfg, agentId });
     const manager = await QmdMemoryManager.create({ cfg, agentId, resolved });

src/memory/qmd-manager.ts

@@ -76,6 +76,14 @@ export class QmdMemoryManager implements MemorySearchManager {
     string,
     { rel: string; abs: string; source: MemorySource }
   >();
+  private readonly exportedSessionState = new Map<
+    string,
+    {
+      hash: string;
+      mtimeMs: number;
+      target: string;
+    }
+  >();
   private readonly maxQmdOutputChars = MAX_QMD_OUTPUT_CHARS;
   private readonly sessionExporter: SessionExporterConfig | null;
   private updateTimer: NodeJS.Timeout | null = null;
@@ -662,6 +670,7 @@ export class QmdMemoryManager implements MemorySearchManager {
     await fs.mkdir(exportDir, { recursive: true });
     const files = await listSessionFilesForAgent(this.agentId);
     const keep = new Set<string>();
+    const tracked = new Set<string>();
     const cutoff = this.sessionExporter.retentionMs
       ? Date.now() - this.sessionExporter.retentionMs
       : null;
@@ -674,7 +683,16 @@ export class QmdMemoryManager implements MemorySearchManager {
         continue;
       }
       const target = path.join(exportDir, `${path.basename(sessionFile, ".jsonl")}.md`);
-      await fs.writeFile(target, this.renderSessionMarkdown(entry), "utf-8");
+      tracked.add(sessionFile);
+      const state = this.exportedSessionState.get(sessionFile);
+      if (!state || state.hash !== entry.hash || state.mtimeMs !== entry.mtimeMs) {
+        await fs.writeFile(target, this.renderSessionMarkdown(entry), "utf-8");
+      }
+      this.exportedSessionState.set(sessionFile, {
+        hash: entry.hash,
+        mtimeMs: entry.mtimeMs,
+        target,
+      });
       keep.add(target);
     }
     const exported = await fs.readdir(exportDir).catch(() => []);
@@ -687,6 +705,11 @@ export class QmdMemoryManager implements MemorySearchManager {
         await fs.rm(full, { force: true });
       }
     }
+    for (const [sessionFile, state] of this.exportedSessionState) {
+      if (!tracked.has(sessionFile) || !state.target.startsWith(exportDir + path.sep)) {
+        this.exportedSessionState.delete(sessionFile);
+      }
+    }
   }
 
   private renderSessionMarkdown(entry: SessionFileEntry): string {