diff --git a/src/ix/genai/ollama_client.py b/src/ix/genai/ollama_client.py
new file mode 100644
index 0000000..21ca11e
--- /dev/null
+++ b/src/ix/genai/ollama_client.py
@@ -0,0 +1,203 @@
+"""OllamaClient — real :class:`GenAIClient` implementation (spec §6 GenAIStep).
+
+Wraps the Ollama ``/api/chat`` structured-output endpoint. Per spec:
+
+* POST ``{base_url}/api/chat`` with ``format = <pydantic JSON schema>``,
+  ``stream = false``, and ``options`` carrying provider-neutral knobs
+  (``temperature`` mapped, ``reasoning_effort`` dropped — Ollama ignores it).
+* Messages are passed through. Content-parts lists (``[{"type":"text",...}]``)
+  are joined to a single string because MVP models (``gpt-oss:20b`` /
+  ``qwen2.5:32b``) don't accept native content-parts.
+* Per-call timeout is enforced via ``httpx``. A connection refusal, read
+  timeout, or 5xx maps to ``IX_002_000``. A 2xx whose ``message.content`` is
+  not valid JSON for the schema maps to ``IX_002_001``.
+
+``selfcheck()`` targets ``/api/tags`` with a fixed 5 s timeout and is what
+``/healthz`` consumes.
+"""
+
+from __future__ import annotations
+
+from typing import Any, Literal
+
+import httpx
+from pydantic import BaseModel, ValidationError
+
+from ix.errors import IXErrorCode, IXException
+from ix.genai.client import GenAIInvocationResult, GenAIUsage
+
+_OLLAMA_TAGS_TIMEOUT_S: float = 5.0
+_BODY_SNIPPET_MAX_CHARS: int = 240
+
+
+class OllamaClient:
+    """Async Ollama backend satisfying :class:`~ix.genai.client.GenAIClient`.
+
+    Parameters
+    ----------
+    base_url:
+        Root URL of the Ollama server (e.g. ``http://host.docker.internal:11434``).
+        Trailing slashes are stripped.
+    per_call_timeout_s:
+        Hard per-call timeout for ``/api/chat``. Spec default: 1500 s.
+    """
+
+    def __init__(self, base_url: str, per_call_timeout_s: float) -> None:
+        self._base_url = base_url.rstrip("/")
+        self._per_call_timeout_s = per_call_timeout_s
+
+    async def invoke(
+        self,
+        request_kwargs: dict[str, Any],
+        response_schema: type[BaseModel],
+    ) -> GenAIInvocationResult:
+        """Run one structured-output chat call; parse into ``response_schema``."""
+
+        body = self._translate_request(request_kwargs, response_schema)
+        url = f"{self._base_url}/api/chat"
+
+        try:
+            async with httpx.AsyncClient(timeout=self._per_call_timeout_s) as http:
+                resp = await http.post(url, json=body)
+        except httpx.HTTPError as exc:
+            raise IXException(
+                IXErrorCode.IX_002_000,
+                detail=f"ollama {exc.__class__.__name__}: {exc}",
+            ) from exc
+        except (ConnectionError, TimeoutError) as exc:  # pragma: no cover - httpx wraps these
+            raise IXException(
+                IXErrorCode.IX_002_000,
+                detail=f"ollama {exc.__class__.__name__}: {exc}",
+            ) from exc
+
+        if resp.status_code >= 500:
+            raise IXException(
+                IXErrorCode.IX_002_000,
+                detail=(
+                    f"ollama HTTP {resp.status_code}: "
+                    f"{resp.text[:_BODY_SNIPPET_MAX_CHARS]}"
+                ),
+            )
+        if resp.status_code >= 400:
+            raise IXException(
+                IXErrorCode.IX_002_000,
+                detail=(
+                    f"ollama HTTP {resp.status_code}: "
+                    f"{resp.text[:_BODY_SNIPPET_MAX_CHARS]}"
+                ),
+            )
+
+        try:
+            payload = resp.json()
+        except ValueError as exc:
+            raise IXException(
+                IXErrorCode.IX_002_000,
+                detail=f"ollama non-JSON body: {resp.text[:_BODY_SNIPPET_MAX_CHARS]}",
+            ) from exc
+
+        content = (payload.get("message") or {}).get("content") or ""
+        try:
+            parsed = response_schema.model_validate_json(content)
+        except ValidationError as exc:
+            raise IXException(
+                IXErrorCode.IX_002_001,
+                detail=(
+                    f"{response_schema.__name__}: {exc.__class__.__name__}: "
+                    f"body={content[:_BODY_SNIPPET_MAX_CHARS]}"
+                ),
+            ) from exc
+        except ValueError as exc:
+            # ``model_validate_json`` raises ValueError on invalid JSON (not
+            # a ValidationError). Treat as structured-output failure.
+            raise IXException(
+                IXErrorCode.IX_002_001,
+                detail=(
+                    f"{response_schema.__name__}: invalid JSON: "
+                    f"body={content[:_BODY_SNIPPET_MAX_CHARS]}"
+                ),
+            ) from exc
+
+        usage = GenAIUsage(
+            prompt_tokens=int(payload.get("prompt_eval_count") or 0),
+            completion_tokens=int(payload.get("eval_count") or 0),
+        )
+        model_name = str(payload.get("model") or request_kwargs.get("model") or "")
+        return GenAIInvocationResult(parsed=parsed, usage=usage, model_name=model_name)
+
+    async def selfcheck(
+        self, expected_model: str
+    ) -> Literal["ok", "degraded", "fail"]:
+        """Probe ``/api/tags`` for ``/healthz``.
+
+        ``ok`` when the server answers 2xx and ``expected_model`` is listed;
+        ``degraded`` when reachable but the model is missing; ``fail``
+        otherwise. Spec §5, §11.
+        """
+
+        try:
+            async with httpx.AsyncClient(timeout=_OLLAMA_TAGS_TIMEOUT_S) as http:
+                resp = await http.get(f"{self._base_url}/api/tags")
+        except (httpx.HTTPError, ConnectionError, TimeoutError):
+            return "fail"
+
+        if resp.status_code != 200:
+            return "fail"
+
+        try:
+            payload = resp.json()
+        except ValueError:
+            return "fail"
+
+        models = payload.get("models") or []
+        names = {str(entry.get("name", "")) for entry in models}
+        if expected_model in names:
+            return "ok"
+        return "degraded"
+
+    def _translate_request(
+        self,
+        request_kwargs: dict[str, Any],
+        response_schema: type[BaseModel],
+    ) -> dict[str, Any]:
+        """Map provider-neutral kwargs to Ollama's /api/chat body."""
+
+        messages = self._translate_messages(
+            list(request_kwargs.get("messages") or [])
+        )
+        body: dict[str, Any] = {
+            "model": request_kwargs.get("model"),
+            "messages": messages,
+            "stream": False,
+            "format": response_schema.model_json_schema(),
+        }
+
+        options: dict[str, Any] = {}
+        if "temperature" in request_kwargs:
+            options["temperature"] = request_kwargs["temperature"]
+        # reasoning_effort intentionally dropped — Ollama doesn't support it.
+        if options:
+            body["options"] = options
+        return body
+
+    @staticmethod
+    def _translate_messages(
+        messages: list[dict[str, Any]],
+    ) -> list[dict[str, Any]]:
+        """Collapse content-parts lists into single strings for Ollama."""
+        out: list[dict[str, Any]] = []
+        for msg in messages:
+            content = msg.get("content")
+            if isinstance(content, list):
+                text_parts = [
+                    str(part.get("text", ""))
+                    for part in content
+                    if isinstance(part, dict) and part.get("type") == "text"
+                ]
+                new_content = "\n".join(text_parts)
+            else:
+                new_content = content
+            out.append({**msg, "content": new_content})
+        return out
+
+
+__all__ = ["OllamaClient"]
diff --git a/tests/live/__init__.py b/tests/live/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/live/test_ollama_client_live.py b/tests/live/test_ollama_client_live.py
new file mode 100644
index 0000000..dd9eb26
--- /dev/null
+++ b/tests/live/test_ollama_client_live.py
@@ -0,0 +1,70 @@
+"""Live tests for :class:`OllamaClient` — gated on ``IX_TEST_OLLAMA=1``.
+
+Never runs in CI (Forgejo runner has no LAN access to Ollama). Run locally::
+
+    IX_TEST_OLLAMA=1 uv run pytest tests/live/test_ollama_client_live.py -v
+
+Assumes the Ollama server at ``http://192.168.68.42:11434`` already has
+``gpt-oss:20b`` pulled.
+"""
+
+from __future__ import annotations
+
+import os
+
+import pytest
+
+from ix.genai.ollama_client import OllamaClient
+from ix.use_cases.bank_statement_header import BankStatementHeader
+
+pytestmark = [
+    pytest.mark.live,
+    pytest.mark.skipif(
+        os.environ.get("IX_TEST_OLLAMA") != "1",
+        reason="live: IX_TEST_OLLAMA=1 required",
+    ),
+]
+
+_OLLAMA_URL = "http://192.168.68.42:11434"
+_MODEL = "gpt-oss:20b"
+
+
+async def test_structured_output_round_trip() -> None:
+    """Real Ollama returns a parsed BankStatementHeader instance."""
+    client = OllamaClient(base_url=_OLLAMA_URL, per_call_timeout_s=300.0)
+    result = await client.invoke(
+        request_kwargs={
+            "model": _MODEL,
+            "messages": [
+                {
+                    "role": "system",
+                    "content": (
+                        "You extract bank statement header fields. "
+                        "Return valid JSON matching the given schema. "
+                        "Do not invent values."
+                    ),
+                },
+                {
+                    "role": "user",
+                    "content": (
+                        "Bank: Deutsche Kreditbank (DKB)\n"
+                        "Currency: EUR\n"
+                        "IBAN: DE89370400440532013000\n"
+                        "Period: 2025-01-01 to 2025-01-31"
+                    ),
+                },
+            ],
+        },
+        response_schema=BankStatementHeader,
+    )
+    assert isinstance(result.parsed, BankStatementHeader)
+    assert isinstance(result.parsed.bank_name, str)
+    assert result.parsed.bank_name  # non-empty
+    assert isinstance(result.parsed.currency, str)
+    assert result.model_name  # server echoes a model name
+
+
+async def test_selfcheck_ok_against_real_server() -> None:
+    """``selfcheck`` returns ``ok`` when the target model is pulled."""
+    client = OllamaClient(base_url=_OLLAMA_URL, per_call_timeout_s=5.0)
+    assert await client.selfcheck(expected_model=_MODEL) == "ok"
diff --git a/tests/unit/test_ollama_client.py b/tests/unit/test_ollama_client.py
new file mode 100644
index 0000000..bf6254a
--- /dev/null
+++ b/tests/unit/test_ollama_client.py
@@ -0,0 +1,258 @@
+"""Tests for :class:`OllamaClient` — hermetic, pytest-httpx-driven.
+
+Covers spec §6 GenAIStep Ollama call contract:
+
+* POST body shape (model / messages / format / stream / options).
+* Response parsing → :class:`GenAIInvocationResult`.
+* Error mapping: connection / timeout / 5xx → ``IX_002_000``;
+  schema-violating body → ``IX_002_001``.
+* ``selfcheck()``: tags-reachable + model-listed → ``ok``;
+  reachable-but-missing → ``degraded``; unreachable → ``fail``.
+"""
+
+from __future__ import annotations
+
+import httpx
+import pytest
+from pydantic import BaseModel
+from pytest_httpx import HTTPXMock
+
+from ix.errors import IXErrorCode, IXException
+from ix.genai.ollama_client import OllamaClient
+
+
+class _Schema(BaseModel):
+    """Trivial structured-output schema for the round-trip tests."""
+
+    bank_name: str
+    account_number: str | None = None
+
+
+def _ollama_chat_ok_body(content_json: str) -> dict:
+    """Build a minimal Ollama /api/chat success body."""
+    return {
+        "model": "gpt-oss:20b",
+        "message": {"role": "assistant", "content": content_json},
+        "done": True,
+        "eval_count": 42,
+        "prompt_eval_count": 17,
+    }
+
+
+class TestInvokeHappyPath:
+    async def test_posts_to_chat_endpoint_with_format_and_no_stream(
+        self, httpx_mock: HTTPXMock
+    ) -> None:
+        httpx_mock.add_response(
+            url="http://ollama.test:11434/api/chat",
+            method="POST",
+            json=_ollama_chat_ok_body('{"bank_name":"DKB","account_number":"DE89"}'),
+        )
+
+        client = OllamaClient(
+            base_url="http://ollama.test:11434", per_call_timeout_s=5.0
+        )
+        result = await client.invoke(
+            request_kwargs={
+                "model": "gpt-oss:20b",
+                "messages": [
+                    {"role": "system", "content": "You extract."},
+                    {"role": "user", "content": "Doc body"},
+                ],
+                "temperature": 0.2,
+                "reasoning_effort": "high",  # dropped silently
+            },
+            response_schema=_Schema,
+        )
+
+        assert result.parsed == _Schema(bank_name="DKB", account_number="DE89")
+        assert result.model_name == "gpt-oss:20b"
+        assert result.usage.prompt_tokens == 17
+        assert result.usage.completion_tokens == 42
+
+        # Verify request shape.
+        requests = httpx_mock.get_requests()
+        assert len(requests) == 1
+        body = requests[0].read().decode()
+        import json
+
+        body_json = json.loads(body)
+        assert body_json["model"] == "gpt-oss:20b"
+        assert body_json["stream"] is False
+        assert body_json["format"] == _Schema.model_json_schema()
+        assert body_json["options"]["temperature"] == 0.2
+        assert "reasoning_effort" not in body_json
+        assert body_json["messages"] == [
+            {"role": "system", "content": "You extract."},
+            {"role": "user", "content": "Doc body"},
+        ]
+
+    async def test_text_parts_content_list_is_joined(
+        self, httpx_mock: HTTPXMock
+    ) -> None:
+        httpx_mock.add_response(
+            url="http://ollama.test:11434/api/chat",
+            method="POST",
+            json=_ollama_chat_ok_body('{"bank_name":"X"}'),
+        )
+        client = OllamaClient(
+            base_url="http://ollama.test:11434", per_call_timeout_s=5.0
+        )
+        await client.invoke(
+            request_kwargs={
+                "model": "gpt-oss:20b",
+                "messages": [
+                    {
+                        "role": "user",
+                        "content": [
+                            {"type": "text", "text": "part-a"},
+                            {"type": "text", "text": "part-b"},
+                        ],
+                    }
+                ],
+            },
+            response_schema=_Schema,
+        )
+        import json
+
+        request_body = json.loads(httpx_mock.get_requests()[0].read())
+        assert request_body["messages"] == [
+            {"role": "user", "content": "part-a\npart-b"}
+        ]
+
+
+class TestInvokeErrorPaths:
+    async def test_connection_error_maps_to_002_000(
+        self, httpx_mock: HTTPXMock
+    ) -> None:
+        httpx_mock.add_exception(httpx.ConnectError("refused"))
+        client = OllamaClient(
+            base_url="http://ollama.test:11434", per_call_timeout_s=1.0
+        )
+        with pytest.raises(IXException) as ei:
+            await client.invoke(
+                request_kwargs={
+                    "model": "gpt-oss:20b",
+                    "messages": [{"role": "user", "content": "hi"}],
+                },
+                response_schema=_Schema,
+            )
+        assert ei.value.code is IXErrorCode.IX_002_000
+
+    async def test_read_timeout_maps_to_002_000(self, httpx_mock: HTTPXMock) -> None:
+        httpx_mock.add_exception(httpx.ReadTimeout("slow"))
+        client = OllamaClient(
+            base_url="http://ollama.test:11434", per_call_timeout_s=0.5
+        )
+        with pytest.raises(IXException) as ei:
+            await client.invoke(
+                request_kwargs={
+                    "model": "gpt-oss:20b",
+                    "messages": [{"role": "user", "content": "hi"}],
+                },
+                response_schema=_Schema,
+            )
+        assert ei.value.code is IXErrorCode.IX_002_000
+
+    async def test_500_maps_to_002_000_with_body_snippet(
+        self, httpx_mock: HTTPXMock
+    ) -> None:
+        httpx_mock.add_response(
+            url="http://ollama.test:11434/api/chat",
+            method="POST",
+            status_code=500,
+            text="boom boom server broken",
+        )
+        client = OllamaClient(
+            base_url="http://ollama.test:11434", per_call_timeout_s=5.0
+        )
+        with pytest.raises(IXException) as ei:
+            await client.invoke(
+                request_kwargs={
+                    "model": "gpt-oss:20b",
+                    "messages": [{"role": "user", "content": "hi"}],
+                },
+                response_schema=_Schema,
+            )
+        assert ei.value.code is IXErrorCode.IX_002_000
+        assert "boom" in (ei.value.detail or "")
+
+    async def test_200_with_invalid_json_maps_to_002_001(
+        self, httpx_mock: HTTPXMock
+    ) -> None:
+        httpx_mock.add_response(
+            url="http://ollama.test:11434/api/chat",
+            method="POST",
+            json=_ollama_chat_ok_body("not-json"),
+        )
+        client = OllamaClient(
+            base_url="http://ollama.test:11434", per_call_timeout_s=5.0
+        )
+        with pytest.raises(IXException) as ei:
+            await client.invoke(
+                request_kwargs={
+                    "model": "gpt-oss:20b",
+                    "messages": [{"role": "user", "content": "hi"}],
+                },
+                response_schema=_Schema,
+            )
+        assert ei.value.code is IXErrorCode.IX_002_001
+
+    async def test_200_with_schema_violation_maps_to_002_001(
+        self, httpx_mock: HTTPXMock
+    ) -> None:
+        # Missing required `bank_name` field.
+        httpx_mock.add_response(
+            url="http://ollama.test:11434/api/chat",
+            method="POST",
+            json=_ollama_chat_ok_body('{"account_number":"DE89"}'),
+        )
+        client = OllamaClient(
+            base_url="http://ollama.test:11434", per_call_timeout_s=5.0
+        )
+        with pytest.raises(IXException) as ei:
+            await client.invoke(
+                request_kwargs={
+                    "model": "gpt-oss:20b",
+                    "messages": [{"role": "user", "content": "hi"}],
+                },
+                response_schema=_Schema,
+            )
+        assert ei.value.code is IXErrorCode.IX_002_001
+
+
+class TestSelfcheck:
+    async def test_selfcheck_ok_when_model_listed(
+        self, httpx_mock: HTTPXMock
+    ) -> None:
+        httpx_mock.add_response(
+            url="http://ollama.test:11434/api/tags",
+            method="GET",
+            json={"models": [{"name": "gpt-oss:20b"}, {"name": "qwen2.5:32b"}]},
+        )
+        client = OllamaClient(
+            base_url="http://ollama.test:11434", per_call_timeout_s=5.0
+        )
+        assert await client.selfcheck(expected_model="gpt-oss:20b") == "ok"
+
+    async def test_selfcheck_degraded_when_model_missing(
+        self, httpx_mock: HTTPXMock
+    ) -> None:
+        httpx_mock.add_response(
+            url="http://ollama.test:11434/api/tags",
+            method="GET",
+            json={"models": [{"name": "qwen2.5:32b"}]},
+        )
+        client = OllamaClient(
+            base_url="http://ollama.test:11434", per_call_timeout_s=5.0
+        )
+        assert await client.selfcheck(expected_model="gpt-oss:20b") == "degraded"
+
+    async def test_selfcheck_fail_on_connection_error(
+        self, httpx_mock: HTTPXMock
+    ) -> None:
+        httpx_mock.add_exception(httpx.ConnectError("refused"))
+        client = OllamaClient(
+            base_url="http://ollama.test:11434", per_call_timeout_s=5.0
+        )
+        assert await client.selfcheck(expected_model="gpt-oss:20b") == "fail"