Memory/QMD: cap qmd command output buffering

CHANGELOG.md

@@ -67,6 +67,7 @@ Docs: https://docs.openclaw.ai
 - Cron: repair missing/corrupt `nextRunAtMs` for the updated job without globally recomputing unrelated due jobs during `cron update`. (#15750)
 - Discord: prefer gateway guild id when logging inbound messages so cached-miss guilds do not appear as `guild=dm`. Thanks @thewilloftheshadow.
 - TUI: refactor searchable select list description layout and add regression coverage for ANSI-highlight width bounds.
+- Memory/QMD: cap QMD command output buffering to prevent memory exhaustion from pathological `qmd` command output.
 - 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

@@ -829,6 +829,30 @@ describe("QmdMemoryManager", () => {
     await manager.close();
   });
 
+  it("errors when qmd output exceeds command output safety cap", async () => {
+    const noisyPayload = "x".repeat(240_000);
+    spawnMock.mockImplementation((_cmd: string, args: string[]) => {
+      if (args[0] === "search") {
+        const child = createMockChild({ autoClose: false });
+        emitAndClose(child, "stdout", noisyPayload);
+        return child;
+      }
+      return createMockChild();
+    });
+
+    const resolved = resolveMemoryBackendConfig({ cfg, agentId });
+    const manager = await QmdMemoryManager.create({ cfg, agentId, resolved });
+    expect(manager).toBeTruthy();
+    if (!manager) {
+      throw new Error("manager missing");
+    }
+
+    await expect(
+      manager.search("noise", { sessionKey: "agent:main:slack:dm:u123" }),
+    ).rejects.toThrow(/too much output/);
+    await manager.close();
+  });
+
   it("treats plain-text no-results stdout as an empty result set", async () => {
     spawnMock.mockImplementation((_cmd: string, args: string[]) => {
       if (args[0] === "search") {

src/memory/qmd-manager.ts

@@ -30,6 +30,7 @@ const log = createSubsystemLogger("memory");
 
 const SNIPPET_HEADER_RE = /@@\s*-([0-9]+),([0-9]+)/;
 const SEARCH_PENDING_UPDATE_WAIT_MS = 500;
+const MAX_QMD_OUTPUT_CHARS = 200_000;
 
 type CollectionRoot = {
   path: string;
@@ -74,6 +75,7 @@ export class QmdMemoryManager implements MemorySearchManager {
     string,
     { rel: string; abs: string; source: MemorySource }
   >();
+  private readonly maxQmdOutputChars = MAX_QMD_OUTPUT_CHARS;
   private readonly sessionExporter: SessionExporterConfig | null;
   private updateTimer: NodeJS.Timeout | null = null;
   private pendingUpdate: Promise<void> | null = null;
@@ -562,6 +564,8 @@ export class QmdMemoryManager implements MemorySearchManager {
       });
       let stdout = "";
       let stderr = "";
+      let stdoutTruncated = false;
+      let stderrTruncated = false;
       const timer = opts?.timeoutMs
         ? setTimeout(() => {
             child.kill("SIGKILL");
@@ -569,10 +573,14 @@ export class QmdMemoryManager implements MemorySearchManager {
           }, opts.timeoutMs)
         : null;
       child.stdout.on("data", (data) => {
-        stdout += data.toString();
+        const next = appendOutputWithCap(stdout, data.toString("utf8"), this.maxQmdOutputChars);
+        stdout = next.text;
+        stdoutTruncated = stdoutTruncated || next.truncated;
       });
       child.stderr.on("data", (data) => {
-        stderr += data.toString();
+        const next = appendOutputWithCap(stderr, data.toString("utf8"), this.maxQmdOutputChars);
+        stderr = next.text;
+        stderrTruncated = stderrTruncated || next.truncated;
       });
       child.on("error", (err) => {
         if (timer) {
@@ -584,6 +592,14 @@ export class QmdMemoryManager implements MemorySearchManager {
         if (timer) {
           clearTimeout(timer);
         }
+        if (stdoutTruncated || stderrTruncated) {
+          reject(
+            new Error(
+              `qmd ${args.join(" ")} produced too much output (limit ${this.maxQmdOutputChars} chars)`,
+            ),
+          );
+          return;
+        }
         if (code === 0) {
           resolve({ stdout, stderr });
         } else {
@@ -951,3 +967,15 @@ export class QmdMemoryManager implements MemorySearchManager {
     return [command, query, "--json"];
   }
 }
+
+function appendOutputWithCap(
+  current: string,
+  chunk: string,
+  maxChars: number,
+): { text: string; truncated: boolean } {
+  const appended = current + chunk;
+  if (appended.length <= maxChars) {
+    return { text: appended, truncated: false };
+  }
+  return { text: appended.slice(-maxChars), truncated: true };
+}