diff --git a/src/commands/agent.mjs b/src/commands/agent.mjs
index 8835605..f747413 100644
--- a/src/commands/agent.mjs
+++ b/src/commands/agent.mjs
@@ -1,6 +1,7 @@
 // Agent commands: run a coding agent headlessly + list supported agents.
 
 import { getRunProfile, AGENTS, RUN_PROFILES } from "../registry.mjs";
+import { classifyAgentExit } from "../exit-codes.mjs";
 import { runTask } from "../run.mjs";
 import { normalizeLine } from "../run-events.mjs";
 import { renderTextEvent, handleInlineHitl } from "../render.mjs";
@@ -61,7 +62,7 @@ export async function cmdAgentRun(runArgs) {
 
   const { code, signal } = await promise;
   if (timeoutHandle) clearTimeout(timeoutHandle);
-  return code ?? (signal ? 130 : 1);
+  return classifyAgentExit({ code, signal }).exitCode;
 }
 
 function parseRunArgs(argv) {
diff --git a/src/commands/workflow.mjs b/src/commands/workflow.mjs
index 9189404..b8d2aee 100644
--- a/src/commands/workflow.mjs
+++ b/src/commands/workflow.mjs
@@ -21,6 +21,7 @@ import {
   stateShow,
 } from "../factory/state.mjs";
 import { printWorkflowHelp } from "../help.mjs";
+import { classifyWorkflowStatus } from "../exit-codes.mjs";
 
 const RUNS_DIR = ".adlc/workflows/runs";
 
@@ -171,7 +172,10 @@ async function cmdWorkflowRun(rest, rawArgv) {
     if (state.status === RunStatus.PAUSED) {
       console.log(`\nPaused at gate. Resume with: adlc-cli workflow resume ${state.runId} --input <verdict>=<choice>`);
     }
-    return state.status === RunStatus.COMPLETED ? 0 : 1;
+    // Lane contract: PAUSED exits 3 so the Argo expression
+    // `asInt(lastRetry.exitCode) != 10 && asInt(lastRetry.exitCode) != 3`
+    // excludes it from retries.
+    return classifyWorkflowStatus(state.status).exitCode;
   } catch (exc) {
     if (exc instanceof LeaseHeldError) {
       console.error(`Error: ${exc.message}`);
@@ -212,7 +216,10 @@ async function cmdWorkflowResume(rest, rawArgv) {
     if (state.status === RunStatus.PAUSED) {
       console.log(`\nStill paused. Resume with: adlc-cli workflow resume ${state.runId} --input <verdict>=<choice>`);
     }
-    return state.status === RunStatus.COMPLETED ? 0 : 1;
+    // Lane contract: PAUSED exits 3 so the Argo expression
+    // `asInt(lastRetry.exitCode) != 10 && asInt(lastRetry.exitCode) != 3`
+    // excludes it from retries.
+    return classifyWorkflowStatus(state.status).exitCode;
   } catch (exc) {
     if (exc instanceof LeaseHeldError) {
       console.error(`Error: ${exc.message}`);
diff --git a/src/dispatch.mjs b/src/dispatch.mjs
index 07350f1..0ec7c8e 100644
--- a/src/dispatch.mjs
+++ b/src/dispatch.mjs
@@ -40,9 +40,12 @@ function runLegacyTree({ command, args, flags }) {
     case "agents":
       return cmdAgentList();
     case "help":
-    default:
       printHelp();
       return 0;
+    default:
+      console.error(`Unknown command: "${command}"`);
+      printHelp();
+      return 1;
   }
 }
 
@@ -155,6 +158,7 @@ function runNewTree({ command, args, flags }, argv) {
       printCliHelp();
       return 0;
     default:
+      console.error(`Unknown command: "${command}"`);
       printCliHelp();
       return 1;
   }
diff --git a/src/exit-codes.mjs b/src/exit-codes.mjs
new file mode 100644
index 0000000..57fac53
--- /dev/null
+++ b/src/exit-codes.mjs
@@ -0,0 +1,26 @@
+// Machine-readable CLI exit codes (mission tikalk/adlc-cli#22).
+//
+// Pure classifiers — no side effects, no imports. Callers:
+//   - src/commands/agent.mjs    → classifyAgentExit (post-spawn child result)
+//   - src/commands/workflow.mjs → classifyWorkflowStatus (terminal run status)
+
+export function classifyAgentExit({ code, signal } = {}) {
+  if (signal) return { exitCode: 130 };
+  if (code === 0) return { exitCode: 0 };
+  return { exitCode: 10 };
+}
+
+export function classifyWorkflowStatus(status) {
+  switch (status) {
+    case "COMPLETED":
+      return { exitCode: 0 };
+    case "PAUSED":
+      return { exitCode: 3 };
+    case "FAILED":
+      return { exitCode: 10 };
+    case "ABORTED":
+      return { exitCode: 1 };
+    default:
+      return { exitCode: 1 };
+  }
+}
diff --git a/tests/cli-failsafe.test.mjs b/tests/cli-failsafe.test.mjs
new file mode 100644
index 0000000..4bbb941
--- /dev/null
+++ b/tests/cli-failsafe.test.mjs
@@ -0,0 +1,117 @@
+// cli-failsafe contract (mission tikalk/adlc-cli#22): unknown verbs fail safe,
+// agent/workflow exit codes are machine-readable.
+//
+// ASSUMED M2 IMPORT SURFACE (for the implementer — static form):
+//   import { classifyAgentExit } from "../src/exit-codes.mjs";
+//     classifyAgentExit({ code, signal }) -> { exitCode }
+//       { code: 0 }                    -> { exitCode: 0 }
+//       { code: 1..125, no signal }    -> { exitCode: 10 }
+//       { signal: "SIGTERM" }          -> { exitCode: 130 }
+//       { code: null, signal: "SIGKILL" } -> { exitCode: 130 }
+//   import { classifyWorkflowStatus } from "../src/exit-codes.mjs";
+//     classifyWorkflowStatus(status) -> { exitCode }
+//       "COMPLETED" -> { exitCode: 0 }
+//       "PAUSED"    -> { exitCode: 3 }
+//       "FAILED"    -> { exitCode: 10 }
+//       "ABORTED"   -> { exitCode: 1 }
+// Loaded dynamically below (same path + signatures) so the M1 CLI-behavior
+// tests still execute pre-fix while the seam is missing — each M2 test then
+// fails with "seam missing" until src/exit-codes.mjs exists.
+import { test } from "node:test";
+import assert from "node:assert/strict";
+import { execFile } from "node:child_process";
+import { promisify } from "node:util";
+import { fileURLToPath } from "node:url";
+import path from "node:path";
+
+const exec = promisify(execFile);
+const WORKTREE = path.dirname(path.dirname(fileURLToPath(import.meta.url)));
+const run = (...args) =>
+  exec(process.execPath, ["bin/adlc-cli.mjs", ...args], { cwd: WORKTREE }).catch((e) => e);
+const exitCodeOf = (r) => r.code ?? r.exitCode ?? 0;
+const outputOf = (r) => `${r.stdout ?? ""}\n${r.stderr ?? ""}\n${r.message ?? ""}`;
+
+// Lazily load the (not-yet-implemented) exit-code seam. Pre-fix this throws
+// MODULE_NOT_FOUND and the calling test fails as M2-seam-missing RED.
+async function loadExitCodes() {
+  try {
+    return await import("../src/exit-codes.mjs");
+  } catch (err) {
+    assert.fail(
+      `seam missing: src/exit-codes.mjs not implemented ` +
+        `(expected exports classifyAgentExit({code, signal}) and classifyWorkflowStatus(status)). ` +
+        `Original error: ${err && err.message ? err.message : err}`,
+    );
+  }
+}
+
+// ── M1: unknown top-level verb must fail safe ─────────────────────────────
+
+test("M1: unknown top-level verb exits 1 with a usage hint", async () => {
+  const r = await run("factory-mission", "--issue", "x");
+  assert.equal(exitCodeOf(r), 1, `expected exit 1 for unknown verb, got ${exitCodeOf(r)}`);
+  assert.match(outputOf(r), /unknown|usage|help/i);
+});
+
+// ── M1 guards: existing behavior the fix must not break ───────────────────
+
+test("M1 guard: bare invocation exits 0", async () => {
+  const r = await run();
+  assert.equal(exitCodeOf(r), 0);
+});
+
+test("M1 guard: help exits 0", async () => {
+  const r = await run("help");
+  assert.equal(exitCodeOf(r), 0);
+});
+
+test("M1 guard: run with no prompt exits 1 (existing behavior)", async () => {
+  const r = await run("run");
+  assert.equal(exitCodeOf(r), 1);
+  assert.match(outputOf(r), /task is required/i);
+});
+
+// ── M2: agent child exit classification ───────────────────────────────────
+
+test("M2: classifyAgentExit maps clean exit {code:0} to 0", async () => {
+  const { classifyAgentExit } = await loadExitCodes();
+  assert.equal(classifyAgentExit({ code: 0 }).exitCode, 0);
+});
+
+test("M2: classifyAgentExit maps non-zero child code to 10", async () => {
+  const { classifyAgentExit } = await loadExitCodes();
+  assert.equal(classifyAgentExit({ code: 1 }).exitCode, 10);
+  assert.equal(classifyAgentExit({ code: 125 }).exitCode, 10);
+});
+
+test("M2: classifyAgentExit maps SIGTERM kill to 130", async () => {
+  const { classifyAgentExit } = await loadExitCodes();
+  assert.equal(classifyAgentExit({ code: null, signal: "SIGTERM" }).exitCode, 130);
+});
+
+test("M2: classifyAgentExit maps SIGKILL kill to 130", async () => {
+  const { classifyAgentExit } = await loadExitCodes();
+  assert.equal(classifyAgentExit({ code: null, signal: "SIGKILL" }).exitCode, 130);
+});
+
+// ── M2: workflow terminal-status classification ───────────────────────────
+
+test("M2: classifyWorkflowStatus maps COMPLETED to 0", async () => {
+  const { classifyWorkflowStatus } = await loadExitCodes();
+  assert.equal(classifyWorkflowStatus("COMPLETED").exitCode, 0);
+});
+
+test("M2: classifyWorkflowStatus maps PAUSED to 3", async () => {
+  const { classifyWorkflowStatus } = await loadExitCodes();
+  assert.equal(classifyWorkflowStatus("PAUSED").exitCode, 3);
+});
+
+test("M2: classifyWorkflowStatus maps FAILED to 10", async () => {
+  const { classifyWorkflowStatus } = await loadExitCodes();
+  assert.equal(classifyWorkflowStatus("FAILED").exitCode, 10);
+});
+
+test("M2: classifyWorkflowStatus maps ABORTED to 1", async () => {
+  const { classifyWorkflowStatus } = await loadExitCodes();
+  assert.equal(classifyWorkflowStatus("ABORTED").exitCode, 1);
+});