diff --git a/src/host/host-commands.test.ts b/src/host/host-commands.test.ts
index a9e05b5..943c041 100644
--- a/src/host/host-commands.test.ts
+++ b/src/host/host-commands.test.ts
@@ -113,6 +113,24 @@ describe('parseTimeout', () => {
     expect(() => parseTimeout('abc', 5000)).toThrow(/Invalid timeout/);
     expect(() => parseTimeout('Infinity', 5000)).toThrow(/Invalid timeout/);
   });
+
+  // The tenant-side hm.command dispatcher (agentic-hosting
+  // command-registry.ts) now rejects timeout_ms < 100 with
+  // `invalid_params`. Pre-flight at the CLI surface so the operator
+  // gets a clear local error instead of a confusing two-hop reply.
+  it('rejects values below MIN_TIMEOUT_MS=100ms', () => {
+    expect(() => parseTimeout('99', 5000)).toThrow(/minimum 100ms/);
+    expect(() => parseTimeout('50', 5000)).toThrow(/minimum 100ms/);
+    expect(() => parseTimeout('1', 5000)).toThrow(/minimum 100ms/);
+    // Decimal that floors below the floor still rejected.
+    expect(() => parseTimeout('99.9', 5000)).toThrow(/minimum 100ms/);
+  });
+
+  it('accepts values at and above MIN_TIMEOUT_MS=100ms', () => {
+    expect(parseTimeout('100', 5000)).toBe(100);
+    expect(parseTimeout('100.5', 5000)).toBe(100);  // floor stays at 100
+    expect(parseTimeout('30000', 5000)).toBe(30000);
+  });
 });
 
 describe('targetPayload', () => {
diff --git a/src/host/host-commands.ts b/src/host/host-commands.ts
index f755aaf..73f20a0 100644
--- a/src/host/host-commands.ts
+++ b/src/host/host-commands.ts
@@ -81,13 +81,25 @@ function parseGlobalOpts(cmd: Command): GlobalOpts {
   return cmd.optsWithGlobals<GlobalOpts>();
 }
 
+// Floor used by tenant-side hm.command dispatcher (agentic-hosting
+// command-registry.ts MIN_TIMEOUT_MS). Pre-flighting at the CLI surface
+// avoids the confusing two-hop error path: CLI → manager → tenant rejects
+// with `invalid_params`. Keep aligned with agentic-hosting's constant.
+const MIN_TIMEOUT_MS = 100;
+
 function parseTimeout(raw: string | undefined, fallback: number): number {
   if (!raw) return fallback;
   const n = Number(raw);
   if (!Number.isFinite(n) || n <= 0) {
     throw new Error(`Invalid timeout: ${raw}`);
   }
-  return Math.floor(n);
+  const floored = Math.floor(n);
+  if (floored < MIN_TIMEOUT_MS) {
+    throw new Error(
+      `Invalid timeout: ${raw} (minimum ${MIN_TIMEOUT_MS}ms — values below this are rejected by the tenant dispatcher)`,
+    );
+  }
+  return floored;
 }
 
 function parseEnvPairs(pairs: readonly string[] | undefined): Record<string, string> | undefined {