fix(logs): report line-limit truncation (#123358)

src/cli/logs-cli.test.ts

@@ -208,7 +208,9 @@ describe("logs cli", () => {
 
     expect(stdoutWrites.join("")).toContain("Log file:");
     expect(stdoutWrites.join("")).toContain("raw line");
-    expect(stderrWrites.join("")).toContain("Log tail truncated");
+    expect(stderrWrites.join("")).toContain(
+      "Log tail truncated (increase --limit or --max-bytes).",
+    );
     expect(stderrWrites.join("")).toContain("Log cursor reset");
   });
 

src/cli/logs-cli.ts

@@ -725,7 +725,7 @@ export function registerLogsCli(program: Command) {
           if (
             !emitJsonLine({
               type: "notice",
-              message: "Log tail truncated (increase --max-bytes).",
+              message: "Log tail truncated (increase --limit or --max-bytes).",
             })
           ) {
             return;
@@ -785,7 +785,7 @@ export function registerLogsCli(program: Command) {
           }
         }
         if (payload.truncated) {
-          if (!errorLine("Log tail truncated (increase --max-bytes).")) {
+          if (!errorLine("Log tail truncated (increase --limit or --max-bytes).")) {
             return;
           }
         }

src/logging/log-tail.test.ts

@@ -85,6 +85,26 @@ describe("readConfiguredLogTail", () => {
     expect(result.lines).toEqual(["old line", "recent one", "recent two"]);
   });
 
+  it("reports truncation when the line limit omits complete records", async () => {
+    const { readConfiguredLogTail } = await import("./log-tail.js");
+    const tempDir = tempDirs.make("openclaw-log-tail-");
+    const file = path.join(tempDir, "openclaw-2026-01-22.log");
+    const content = "one\ntwo\nthree\n";
+
+    await fs.writeFile(file, content);
+    setLoggerOverride({ file });
+
+    const result = await readConfiguredLogTail({ limit: 2, maxBytes: 100 });
+
+    expect(result).toMatchObject({
+      lines: ["two", "three"],
+      cursor: Buffer.byteLength(content),
+      size: Buffer.byteLength(content),
+      truncated: true,
+      reset: false,
+    });
+  });
+
   it("falls back only within the active profile's rolling log family", async () => {
     const tempDir = tempDirs.make("openclaw-log-tail-");
     const missing = path.join(tempDir, "openclaw-dev-2026-01-22.log");

src/logging/log-tail.ts

@@ -138,6 +138,7 @@ async function readLogSlice(params: {
       lines = lines.slice(0, -1);
     }
     if (lines.length > limit) {
+      truncated = true;
       lines = lines.slice(lines.length - limit);
     }
 

test/e2e/qa-lab/runtime/remote-log-tailing-runtime.ts

@@ -100,7 +100,11 @@ export async function runRemoteLogTailing(repoRoot: string, outputRoot: string)
       lines: string[];
       truncated: boolean;
     };
-    if (first.lines.length !== 2 || !first.lines.some((line) => line.includes("qa-line-three"))) {
+    if (
+      first.lines.length !== 2 ||
+      !first.lines.some((line) => line.includes("qa-line-three")) ||
+      !first.truncated
+    ) {
       throw new Error(`logs.tail did not honor limit: ${JSON.stringify(first)}`);
     }
     const bounded = (await gateway.call("logs.tail", { limit: 20, maxBytes: 96 })) as {