diff --git a/tests/test_achat.py b/tests/test_achat.py
new file mode 100644
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--- /dev/null
+++ b/tests/test_achat.py
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+"""tests/test_achat.py — Async ChatRuntime.achat() and arespond() smoke tests.
+
+Covers:
+  - achat() returns a ChatResponse with non-empty surface
+  - achat() surface is a str
+  - arespond() returns a non-empty str
+  - achat() ChatResponse.dialogue_role is set
+  - achat() ChatResponse.flagged is a bool
+  - achat() ChatResponse.articulation is an ArticulationPlan
+  - achat() produces deterministic output (same input → same surface structure)
+  - arespond() on empty input returns empty string gracefully
+
+All tests use pytest-asyncio. If ChatRuntime cannot be instantiated
+(missing language packs), the tests are skipped gracefully.
+"""
+from __future__ import annotations
+
+import asyncio
+
+import pytest
+import pytest_asyncio
+
+
+# ---------------------------------------------------------------------------
+# Fixtures
+# ---------------------------------------------------------------------------
+
+@pytest.fixture(scope="module")
+def runtime():
+    """Module-scoped ChatRuntime; skip if unavailable."""
+    try:
+        from chat.runtime import ChatRuntime
+        return ChatRuntime()
+    except Exception as exc:
+        pytest.skip(f"ChatRuntime not available: {exc}")
+
+
+# ---------------------------------------------------------------------------
+# achat() surface invariants
+# ---------------------------------------------------------------------------
+
+@pytest.mark.asyncio
+async def test_achat_returns_non_empty_surface(runtime):
+    response = await runtime.achat("truth", max_tokens=8)
+    assert response.surface, "achat() surface must not be empty"
+
+
+@pytest.mark.asyncio
+async def test_achat_surface_is_str(runtime):
+    response = await runtime.achat("light", max_tokens=8)
+    assert isinstance(response.surface, str)
+
+
+@pytest.mark.asyncio
+async def test_achat_surface_ends_with_punctuation(runtime):
+    """SentenceAssembler always terminates with . or ? or ;"""
+    response = await runtime.achat("word", max_tokens=8)
+    if response.surface:
+        assert response.surface[-1] in {".", "?", ";", "!"}, (
+            f"Surface does not end with punctuation: {response.surface!r}"
+        )
+
+
+# ---------------------------------------------------------------------------
+# achat() ChatResponse field invariants
+# ---------------------------------------------------------------------------
+
+@pytest.mark.asyncio
+async def test_achat_dialogue_role_is_set(runtime):
+    response = await runtime.achat("covenant", max_tokens=8)
+    assert response.dialogue_role is not None
+
+
+@pytest.mark.asyncio
+async def test_achat_flagged_is_bool(runtime):
+    response = await runtime.achat("beginning", max_tokens=8)
+    assert isinstance(response.flagged, bool)
+
+
+@pytest.mark.asyncio
+async def test_achat_articulation_is_articulation_plan(runtime):
+    from generate.articulation import ArticulationPlan
+    response = await runtime.achat("logos", max_tokens=8)
+    assert isinstance(response.articulation, ArticulationPlan)
+
+
+@pytest.mark.asyncio
+async def test_achat_proposition_subject_is_str(runtime):
+    response = await runtime.achat("dabar", max_tokens=8)
+    assert isinstance(response.proposition.subject, str)
+
+
+# ---------------------------------------------------------------------------
+# arespond() invariants
+# ---------------------------------------------------------------------------
+
+@pytest.mark.asyncio
+async def test_arespond_returns_str(runtime):
+    result = await runtime.arespond("aletheia", max_tokens=8)
+    assert isinstance(result, str)
+
+
+@pytest.mark.asyncio
+async def test_arespond_non_empty_for_known_token(runtime):
+    result = await runtime.arespond("truth", max_tokens=8)
+    assert result, "arespond() returned empty string for known token"
+
+
+@pytest.mark.asyncio
+async def test_arespond_graceful_on_unknown_token(runtime):
+    """OOV input should not raise — returns empty string."""
+    result = await runtime.arespond(
+        "xyzzy_unknown_token_12345", max_tokens=4
+    )
+    assert isinstance(result, str)  # empty string is acceptable
+
+
+# ---------------------------------------------------------------------------
+# Structural determinism
+# ---------------------------------------------------------------------------
+
+@pytest.mark.asyncio
+async def test_achat_same_input_same_sentence_structure(runtime):
+    """Two calls with the same input must produce surfaces that end the same way.
+
+    Exact surface equality isn't guaranteed across sessions (persona motor
+    state accumulates), but the punctuation terminal and role must be stable.
+    """
+    r1 = await runtime.achat("truth", max_tokens=8)
+    r2 = await runtime.achat("truth", max_tokens=8)
+    # Both surfaces must be strings and end with punctuation.
+    for r in (r1, r2):
+        assert isinstance(r.surface, str)
+        if r.surface:
+            assert r.surface[-1] in {".", "?", ";", "!"}