diff --git a/.agents/skills/lib_py/agents/__main__.py b/.agents/skills/lib_py/agents/__main__.py
index 760eb35..e9162f9 100644
--- a/.agents/skills/lib_py/agents/__main__.py
+++ b/.agents/skills/lib_py/agents/__main__.py
@@ -117,6 +117,15 @@ def main():
         print(adapter.resume_spec(binary, uuid, materialized=mat))
         sys.exit(0)
 
+    elif cmd == 'auth-ok':
+        # auth-ok <agent>: exit 0 when the adapter's auth_ok() holds, else 1.
+        agent_name = sys.argv[2] if len(sys.argv) > 2 else ''
+        adapter = get_adapter(agent_name)
+        if not adapter:
+            print(f"ERROR: unknown agent {agent_name!r}", file=sys.stderr)
+            sys.exit(1)
+        sys.exit(0 if adapter.auth_ok() else 1)
+
     elif cmd == 'exit-key':
         agent_name = sys.argv[2] if len(sys.argv) > 2 else ''
         adapter = get_adapter(agent_name)
diff --git a/.agents/skills/lib_py/agents/adapters/opencode.py b/.agents/skills/lib_py/agents/adapters/opencode.py
index 628e7ee..bb8ff9b 100644
--- a/.agents/skills/lib_py/agents/adapters/opencode.py
+++ b/.agents/skills/lib_py/agents/adapters/opencode.py
@@ -39,13 +39,6 @@ def _ro_connect(db: str):
 # (binary, HOME, XDG_DATA_HOME) -> the db `debug paths` printed for them.
 _DB_PATHS = {}
 
-_PROVIDER_ENV_VARS = (
-    'ANTHROPIC_API_KEY',
-    'OPENAI_API_KEY',
-    'GEMINI_API_KEY',
-    'GROQ_API_KEY'
-)
-
 class OpenCodeAgentAdapter(BaseAgentAdapter):
     @property
     def name(self) -> str:
@@ -322,11 +315,10 @@ class OpenCodeAgentAdapter(BaseAgentAdapter):
         return f"{binary} --auto --standalone"
 
     def auth_ok(self, run_cmd: Optional[Any] = None) -> bool:
-        if any(os.environ.get(v) for v in _PROVIDER_ENV_VARS):
-            return True
+        # opencode 2.x needs no login: a fresh HOME runs a free default model
+        # and local providers have no key, so the binary is the whole check.
         home = os.environ.get("HOME_DIR") or os.environ.get("HOME") or os.path.expanduser("~")
-        auth_file = f"{home}/.local/share/opencode/auth.json"
-        return os.path.exists(auth_file)
+        return bool(shutil.which("opencode")) or os.path.exists(f"{home}/.opencode/bin/opencode")
 
     def discover(self, ctx: DiscoveryContext) -> list:
         db = self._resolve_db(ctx)
diff --git a/.agents/skills/multi-agent-mux-create/scripts/create_session.sh b/.agents/skills/multi-agent-mux-create/scripts/create_session.sh
index aa3525f..7e9c131 100755
--- a/.agents/skills/multi-agent-mux-create/scripts/create_session.sh
+++ b/.agents/skills/multi-agent-mux-create/scripts/create_session.sh
@@ -143,9 +143,9 @@ elif [ "$AGENT" = "grok" ]; then
     exit 1
   fi
 elif [ "$AGENT" = "opencode" ]; then
-  if [ -f "$HOME/.local/share/opencode/auth.json" ] || [ -n "${ANTHROPIC_API_KEY:-}" ] || [ -n "${OPENAI_API_KEY:-}" ] || [ -n "${GEMINI_API_KEY:-}" ] || [ -n "${GROQ_API_KEY:-}" ]; then
-    true
-  elif ! opencode --version >/dev/null 2>&1; then
+  # opencode needs no login (2.x: a free default model, keyless local
+  # providers); the adapter's auth_ok is the one verdict.
+  if ! "$(_delegate_py_bin)" -m lib_py.agents auth-ok opencode >/dev/null 2>&1; then
     echo "ERROR: opencode is not functional or configured." >&2
     exit 1
   fi
diff --git a/tests/test_a4_adapter_contract.py b/tests/test_a4_adapter_contract.py
index 2affd53..da66364 100644
--- a/tests/test_a4_adapter_contract.py
+++ b/tests/test_a4_adapter_contract.py
@@ -311,16 +311,24 @@ def test_adapter_auth_ok(tmp_path, monkeypatch):
     # Hermes always True
     assert get_adapter('hermes').auth_ok() is True
 
-    # OpenCode auth check (provider env var or auth.json file)
+    # OpenCode auth check: the binary alone (2.x needs no login, Issue #60);
+    # keys and auth.json do not count
     opencode = get_adapter('opencode')
+    path = os.environ["PATH"]
+    monkeypatch.setenv("PATH", str(tmp_path / "empty-bin"))
     assert opencode.auth_ok() is False
     monkeypatch.setenv("ANTHROPIC_API_KEY", "test-key")
-    assert opencode.auth_ok() is True
-    monkeypatch.delenv("ANTHROPIC_API_KEY", raising=False)
     opencode_auth = tmp_path / ".local" / "share" / "opencode" / "auth.json"
     opencode_auth.parent.mkdir(parents=True, exist_ok=True)
     opencode_auth.write_text("{}")
+    assert opencode.auth_ok() is False
+    monkeypatch.delenv("ANTHROPIC_API_KEY", raising=False)
+    opencode_bin = tmp_path / ".opencode" / "bin" / "opencode"
+    opencode_bin.parent.mkdir(parents=True)
+    opencode_bin.write_text("#!/bin/sh\n")
+    opencode_bin.chmod(0o755)
     assert opencode.auth_ok() is True
+    monkeypatch.setenv("PATH", path)
 
     # Codex auth check (env var, auth.json file, or CLI)
     codex = get_adapter('codex')
diff --git a/tests/test_issue60_linux_fixes.py b/tests/test_issue60_linux_fixes.py
index e03ffa3..0b47d9b 100644
--- a/tests/test_issue60_linux_fixes.py
+++ b/tests/test_issue60_linux_fixes.py
@@ -9,6 +9,8 @@
    (binary, HOME, XDG_DATA_HOME) in a process.
 2. A graceful stop whose `/exit` worked says so: the agent exits instead of
    turning `working`, so the delivery is unconfirmed, and no kill step ran.
+3. opencode's auth check is the binary alone (2.x needs no login), and create
+   takes the adapter's verdict instead of running `opencode --version`.
 """
 
 from __future__ import annotations
@@ -279,3 +281,75 @@ def test_the_graceful_stop_reports_what_happened(mam_sandbox, mock_herdr, mock_a
     else:
         # The kill step runs, so it is named.
         assert "still alive → kill-session" in out, out
+
+
+# ---------------------------------------------------------------------------
+# 3. opencode's auth check is the binary
+# ---------------------------------------------------------------------------
+def _executable(path: Path) -> Path:
+    path.parent.mkdir(parents=True, exist_ok=True)
+    path.write_text("#!/bin/sh\n")
+    path.chmod(0o755)
+    return path
+
+
+@pytest.fixture
+def bare_home(tmp_path, monkeypatch):
+    """An empty HOME_DIR and a PATH with no opencode."""
+    monkeypatch.setenv("HOME_DIR", str(tmp_path / "home"))
+    monkeypatch.setenv("PATH", str(tmp_path / "empty-bin"))
+    for var in ("ANTHROPIC_API_KEY", "OPENAI_API_KEY", "GEMINI_API_KEY", "GROQ_API_KEY"):
+        monkeypatch.delenv(var, raising=False)
+    return tmp_path
+
+
+def test_keys_and_auth_json_without_the_binary_are_not_enough(bare_home, monkeypatch):
+    opencode = get_adapter("opencode")
+    assert opencode.auth_ok() is False
+    monkeypatch.setenv("ANTHROPIC_API_KEY", "test-key")
+    assert opencode.auth_ok() is False
+    auth = bare_home / "home" / ".local" / "share" / "opencode" / "auth.json"
+    auth.parent.mkdir(parents=True)
+    auth.write_text("{}")
+    assert opencode.auth_ok() is False
+
+
+@pytest.mark.parametrize("where", ["path", "home"])
+def test_the_binary_alone_is_enough(bare_home, monkeypatch, where):
+    if where == "path":
+        _executable(bare_home / "bin" / "opencode")
+        monkeypatch.setenv("PATH", str(bare_home / "bin"))
+    else:
+        _executable(bare_home / "home" / ".opencode" / "bin" / "opencode")
+    assert get_adapter("opencode").auth_ok() is True
+
+
+def test_the_auth_ok_command_exits_with_the_verdict(bare_home):
+    def rc(*args):
+        env = dict(os.environ, PYTHONPATH=str(SKILLS))
+        return subprocess.run([sys.executable, "-m", "lib_py.agents", "auth-ok", *args],
+                              capture_output=True, text=True, env=env).returncode
+
+    assert rc("opencode") == 1
+    _executable(bare_home / "home" / ".opencode" / "bin" / "opencode")
+    assert rc("opencode") == 0
+    assert rc("no-such-agent") == 1
+
+
+def test_create_decides_opencode_auth_without_running_it(mam_sandbox, mock_herdr, mock_agents, monkeypatch):
+    # Every opencode call create makes is logged; --version was the old check.
+    log = mam_sandbox / "opencode-calls.log"
+    wrap = mam_sandbox / "logbin" / "opencode"
+    wrap.parent.mkdir()
+    wrap.write_text(f'#!/bin/sh\necho "$*" >> "{log}"\nexec "{shutil.which("opencode")}" "$@"\n')
+    wrap.chmod(0o755)
+    monkeypatch.setenv("PATH", f"{wrap.parent}:{os.environ['PATH']}")
+    for var in ("ANTHROPIC_API_KEY", "OPENAI_API_KEY", "GEMINI_API_KEY", "GROQ_API_KEY"):
+        monkeypatch.delenv(var, raising=False)
+    create = mam_sandbox / ".agents" / "skills" / "multi-agent-mux-create" / "scripts" / "create_session.sh"
+    res = subprocess.run(["bash", str(create), "--workspace", str(mam_sandbox), "--agent", "opencode",
+                          "--role", "creator", "--no-onboard"],
+                         capture_output=True, text=True, cwd=str(mam_sandbox), timeout=300)
+    assert res.returncode == 0, res.stdout + res.stderr
+    calls = log.read_text().splitlines() if log.exists() else []
+    assert "--version" not in calls, calls