diff --git a/README.md b/README.md
index a8c3c5d..289093c 100644
--- a/README.md
+++ b/README.md
@@ -55,6 +55,19 @@ unverifiable evidence. See the
 and the
 [OpenAI Agents integration guide](https://github.com/FU-max-boop/agentrunproof/blob/main/docs/openai-agents.md).
 
+Maintaining a downstream library? The
+[isolated, test-only CI guide](https://github.com/FU-max-boop/agentrunproof/blob/main/docs/ci-adoption.md)
+provides a copyable real-`Runner` contract test and an ephemeral `uv` matrix for exact SDK 0.20.0
+and 0.21.0. It keeps AgentRunProof out of runtime metadata and the project lockfile. Provider-free
+means the built-in deterministic model sends no model-provider request; it does not make arbitrary
+downstream code or dependency installation network-isolated.
+
+For artifact review, pin `agentrunproof==0.2.0` and use the immutable
+[v0.2.0 release](https://github.com/FU-max-boop/agentrunproof/releases/tag/v0.2.0), whose
+`SHA256SUMS` binds the wheel and sdist. The release workflow rebuilds and byte-compares those
+artifacts, smoke-tests the wheel, and publishes the same verified files to PyPI through OIDC trusted
+publishing. The CI guide records the exact hashes and the remaining third-party-code trust boundary.
+
 ## Where it fits
 
 Use the SDK's public `agents.testing.ScriptedModel` with `pytest` for a focused deterministic
diff --git a/docs/ci-adoption.md b/docs/ci-adoption.md
new file mode 100644
index 0000000..76d8f2b
--- /dev/null
+++ b/docs/ci-adoption.md
@@ -0,0 +1,130 @@
+# Isolated, test-only CI adoption
+
+Use this pattern when a downstream library wants one real OpenAI Agents SDK `Runner` contract
+test without adding AgentRunProof to its runtime dependencies or project lockfile. The job installs a
+released AgentRunProof version into an ephemeral `uv` environment, executes only the focused test,
+and discards the environment when the job ends.
+
+The checked-in, copyable test is
+[`examples/ci_adoption/test_runner_contract.py`](../examples/ci_adoption/test_runner_contract.py).
+It exercises both `Runner.run()` and `Runner.run_streamed()`, consumes a deterministic two-turn
+model script, and verifies that one local tool is called exactly once. In a downstream repository,
+replace `_build_tool()` with the library's adapter or wrapper while keeping the assertions around
+the real `Runner` paths.
+
+## Run it without changing the project environment
+
+From a checkout of this repository, the following command runs the example against an exact SDK
+release. `--isolated --no-project` tells `uv` to create a temporary environment and not discover the
+checkout's `pyproject.toml`; every dependency needed by this focused test is supplied with
+`--with`.
+
+```bash
+uv run --isolated --no-project --python 3.12 \
+  --with "agentrunproof==0.2.0" \
+  --with "openai-agents==0.20.0" \
+  --with "pytest>=8,<10" \
+  --with "pytest-asyncio>=0.24" \
+  -- python -m pytest -q examples/ci_adoption/test_runner_contract.py
+```
+
+Change only the SDK pin to exercise the other packaged baseline:
+
+```bash
+uv run --isolated --no-project --python 3.12 \
+  --with "agentrunproof==0.2.0" \
+  --with "openai-agents==0.21.0" \
+  --with "pytest>=8,<10" \
+  --with "pytest-asyncio>=0.24" \
+  -- python -m pytest -q examples/ci_adoption/test_runner_contract.py
+```
+
+For a downstream test that imports a `src/`-layout package, add `--with-editable .` before `--`.
+That installs the checkout only inside the same temporary environment; it still does not alter the
+project's dependency metadata or lockfile. If the repository has optional dependencies needed by
+the adapter, name the applicable extra, for example `--with-editable ".[openai]"`.
+
+## Minimal GitHub Actions job
+
+This job is deliberately separate from the downstream project's normal dependency installation.
+It grants read-only repository permission, pins the action and tool revisions, and tests the two
+exact SDK releases covered by AgentRunProof 0.2.0.
+
+```yaml
+name: OpenAI Agents Runner contract
+
+on:
+  pull_request:
+    paths:
+      - "path/to/adapter/**"
+      - "tests/test_openai_agents_runner.py"
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  runner-contract:
+    runs-on: ubuntu-24.04
+    strategy:
+      fail-fast: false
+      matrix:
+        sdk-version: ["0.20.0", "0.21.0"]
+    steps:
+      - uses: actions/checkout@fbc6f3992d24b796d5a048ff273f7fcc4a7b6c09 # v5.1.0
+        with:
+          persist-credentials: false
+      - uses: actions/setup-python@ece7cb06caefa5fff74198d8649806c4678c61a1 # v6.3.0
+        with:
+          python-version: "3.12.13"
+      - uses: astral-sh/setup-uv@20cfd1bf945f4377ade1205e4dbc17946fc9a30d # v10.0.1
+        with:
+          version: "0.12.5"
+      - name: Exercise the adapter through the real Runner
+        run: |
+          uv run --isolated --no-project --python 3.12 \
+            --with-editable . \
+            --with "agentrunproof==0.2.0" \
+            --with "openai-agents==${{ matrix.sdk-version }}" \
+            --with "pytest>=8,<10" \
+            --with "pytest-asyncio>=0.24" \
+            -- python -m pytest -q tests/test_openai_agents_runner.py
+```
+
+Remove `--with-editable .` only when the focused test does not import the downstream package. Keep
+the job focused: AgentRunProof is a test dependency in this environment, not a runtime dependency
+of the package under test.
+
+## What "provider-free" does and does not mean
+
+The example's `DeterministicModel` supplies every model response locally, and `RunConfig` disables
+SDK tracing. Consequently, the test sends no model-provider request and needs no API key.
+
+This is **not** a process-level network sandbox:
+
+- `uv` may contact configured package indexes while resolving and downloading dependencies;
+- a downstream tool, hook, fixture, plugin, or imported package may still use the network; and
+- enabling tracing may let an installed trace processor export data.
+
+Repositories that require full network isolation should prefetch and hash-lock artifacts, then run
+the test under their own egress-deny mechanism. Keep downstream tools synthetic and local unless
+the test intentionally covers an integration boundary.
+
+## Dependency and release trust
+
+- Pin `agentrunproof==0.2.0` and an exact `openai-agents` release in the isolated job. The supported
+  range is `openai-agents>=0.20.0,<0.22`; 0.20.0 and 0.21.0 are the exact packaged CI baselines.
+- The immutable [v0.2.0 GitHub release](https://github.com/FU-max-boop/agentrunproof/releases/tag/v0.2.0)
+  publishes wheel and sdist SHA-256 values in `SHA256SUMS`. Its release workflow re-downloads those
+  assets, compares them byte-for-byte with a rebuild from the tagged source, and smoke-tests the
+  wheel before the same verified files are sent to PyPI through OIDC trusted publishing.
+- The released wheel SHA-256 is
+  `e393e98bf797cc10f07ea151ec6fffd3b1ebbb21307256309e08f11e97a27d51`; the sdist SHA-256 is
+  `c0ad9c2aeb425cfcaff81b6daeee9c9ded069397dfc7a3319fda28f9842f2ace`.
+- A repository with a lock or hash policy should resolve this isolated closure with its normal
+  dependency-review process and commit the resulting test-only lock data. The short `uv run`
+  pattern above intentionally does not create a lockfile.
+
+The package and its transitive dependencies still remain third-party code executed in CI. These
+controls make the scope and artifact identity reviewable; they do not replace the downstream
+maintainer's dependency and supply-chain policy.
diff --git a/examples/ci_adoption/test_runner_contract.py b/examples/ci_adoption/test_runner_contract.py
new file mode 100644
index 0000000..735a817
--- /dev/null
+++ b/examples/ci_adoption/test_runner_contract.py
@@ -0,0 +1,65 @@
+"""Copyable downstream contract test using the real Runner and a local model script."""
+
+from __future__ import annotations
+
+import asyncio
+from typing import Literal
+
+import pytest
+from agents import Agent, FunctionTool, Runner, function_tool
+from agents.run import RunConfig
+
+from agentrunproof import DeterministicModel, assistant_message, function_call
+
+RunMode = Literal["run", "streamed"]
+
+
+def _build_tool(invocations: list[str]) -> FunctionTool:
+    """Replace this function with the downstream library's tool adapter or wrapper."""
+
+    @function_tool
+    def lookup_fixture(key: str) -> str:
+        """Return one synthetic fixture value."""
+
+        invocations.append(key)
+        return "42"
+
+    return lookup_fixture
+
+
+async def _exercise_runner(mode: RunMode) -> tuple[str, list[str]]:
+    invocations: list[str] = []
+    tool = _build_tool(invocations)
+    model = DeterministicModel(
+        [
+            [function_call(tool.name, {"key": "alpha"}, call_id="downstream-contract-call")],
+            [assistant_message("The fixture value is 42.")],
+        ]
+    )
+    agent = Agent(
+        name="Downstream adapter contract",
+        instructions="Call the fixture tool once, then report its value.",
+        model=model,
+        tools=[tool],
+    )
+    run_config = RunConfig(tracing_disabled=True)
+
+    if mode == "streamed":
+        result = Runner.run_streamed(agent, "Look up alpha.", run_config=run_config)
+        async for _ in result.stream_events():
+            pass
+    else:
+        result = await Runner.run(agent, "Look up alpha.", run_config=run_config)
+
+    model.assert_complete()
+    assert len(model.calls) == 2
+    assert all(call.streamed is (mode == "streamed") for call in model.calls)
+    return result.final_output, invocations
+
+
+@pytest.mark.parametrize("mode", ["run", "streamed"])
+def test_adapter_tool_runs_exactly_once_through_real_runner(mode: RunMode) -> None:
+    output, invocations = asyncio.run(_exercise_runner(mode))
+
+    assert output == "The fixture value is 42."
+    assert invocations == ["alpha"]