diff --git a/.github/workflows/extension-package-check.yml b/.github/workflows/extension-package-check.yml
index ae81d145df..828c40c33d 100644
--- a/.github/workflows/extension-package-check.yml
+++ b/.github/workflows/extension-package-check.yml
@@ -53,3 +53,22 @@ jobs:
             uv run --project backend --no-sync python scripts/check_extension.py "$package"
             echo "::endgroup::"
           done
+      # Each package's own tests run in an isolated environment against this
+      # checkout's extension-api, so a contract change that breaks them fails here.
+      - name: Test bundled extension packages that ship tests
+        shell: bash
+        run: |
+          for package in examples/deerflow-extension-*/; do
+            [ -d "${package}tests" ] || continue
+            echo "::group::Test ${package%/}"
+            (
+              cd "$package"
+              uv venv --python 3.12
+              uv pip install -e ../../backend/packages/extension-api
+              uv pip install -e ".[dev]"
+              uv run --no-project pytest -q
+              uv run --no-project ruff check .
+              uv run --no-project ruff format --check .
+            )
+            echo "::endgroup::"
+          done
diff --git a/CHANGELOG.md b/CHANGELOG.md
index c5fe496b20..2352629a65 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1397,6 +1397,12 @@ As of 2026-10-21, the milestone includes **829 merged pull requests**.
 
 ### Fixed
 
+- **examples:** The extension example's package tests pass again. Its test
+  registry lacked `knowledge_provider()`, so it no longer matched the
+  `ExtensionRegistry` protocol and the README's `pytest` run failed. Extension
+  Package Check now also runs the tests of bundled examples that ship them,
+  so a contract change that breaks them fails its pull request. ([#7364])
+  
 - **gateway:** Run requests with a malformed body now get a client error
   instead of `500 Internal Server Error`. A `config.configurable` or
   `config.context` that is not an object, an invalid `assistant_id`, a
@@ -13045,3 +13051,4 @@ with **180 merged pull requests** since the first 2.0 milestone tag.
 [#7325]: https://github.com/bytedance/deer-flow/pull/7325
 [#7326]: https://github.com/bytedance/deer-flow/pull/7326
 [#7362]: https://github.com/bytedance/deer-flow/pull/7362
+[#7364]: https://github.com/bytedance/deer-flow/pull/7364
diff --git a/CHANGELOG_zh.md b/CHANGELOG_zh.md
index a31ff60fc9..f1d4be7fef 100644
--- a/CHANGELOG_zh.md
+++ b/CHANGELOG_zh.md
@@ -1112,6 +1112,11 @@
 
 ### 修复
 
+- **示例：** 扩展示例的包测试重新通过。其测试用 registry 缺少
+  `knowledge_provider()`，不再满足 `ExtensionRegistry` 协议，按 README 运行
+  `pytest` 会失败。Extension Package Check 现在也会运行自带测试的内置示例的测试，
+  因此破坏这些测试的契约变更会在其 PR 中失败。([#7364])
+  
 - **网关：** 请求体格式错误的运行请求现在返回客户端错误，而不是
   `500 Internal Server Error`。此前 `config.configurable` 或 `config.context`
   不是对象、`assistant_id` 无效、`agent_name` 不是字符串，或 AI 消息的 `tool_calls`
@@ -10413,3 +10418,4 @@ DeerFlow 2.0 是围绕"超级智能体"框架的彻底重写，核心包含子
 [#7325]: https://github.com/bytedance/deer-flow/pull/7325
 [#7326]: https://github.com/bytedance/deer-flow/pull/7326
 [#7362]: https://github.com/bytedance/deer-flow/pull/7362
+[#7364]: https://github.com/bytedance/deer-flow/pull/7364
diff --git a/backend/packages/harness/deerflow/extensions/AGENTS.md b/backend/packages/harness/deerflow/extensions/AGENTS.md
index 0401949422..22a06a1521 100644
--- a/backend/packages/harness/deerflow/extensions/AGENTS.md
+++ b/backend/packages/harness/deerflow/extensions/AGENTS.md
@@ -170,10 +170,11 @@ entry, the manager owns the controlled locked sync.
 
 The public package is `packages/extension-api/` and must never import `deerflow` or carry
 framework dependencies. Extensions declare any FastAPI, LangChain, or LangGraph imports
-themselves. Its registry contract exposes eight contribution kinds: middleware
+themselves. Its registry contract exposes nine contribution kinds: middleware
 contributors, task-lifecycle contributors, system-model-call observers, agent-assembly
-observers, context-compaction observers, Gateway-lifetime services, eager routers, and
-experimental full-stack plugins (`registry.plugin()`, see `docs/full-stack-plugins.md`). Middleware contributions declare lead/subagent scope, stable
+observers, context-compaction observers, Gateway-lifetime services, eager routers,
+experimental full-stack plugins (`registry.plugin()`, see `docs/full-stack-plugins.md`),
+and read-only knowledge providers (`registry.knowledge_provider()`, above). Middleware contributions declare lead/subagent scope, stable
 order, and a semantic placement (`MODEL_LOGICAL`, `MODEL_PHYSICAL`, `TOOL_VISIBLE`,
 `TOOL_RAW`, or `STANDARD`) rather than a fragile list index. `extensions/stack.py` is the
 single final composition point; do not inject inside
diff --git a/backend/tests/test_extension_package_ci.py b/backend/tests/test_extension_package_ci.py
new file mode 100644
index 0000000000..1bd9d1081a
--- /dev/null
+++ b/backend/tests/test_extension_package_ci.py
@@ -0,0 +1,59 @@
+"""Keep bundled extension package tests running when the public contract changes."""
+
+from __future__ import annotations
+
+import tomllib
+from pathlib import Path
+
+import pytest
+import yaml
+from packaging.requirements import Requirement
+
+REPO_ROOT = Path(__file__).resolve().parents[2]
+TEST_STEP = "Test bundled extension packages that ship tests"
+
+
+def _workflow() -> dict:
+    # BaseLoader preserves GitHub Actions' `on` key rather than treating it as
+    # YAML 1.1's boolean True.
+    return yaml.load((REPO_ROOT / ".github/workflows/extension-package-check.yml").read_text(encoding="utf-8"), Loader=yaml.BaseLoader)
+
+
+def _test_step() -> dict:
+    steps = _workflow()["jobs"]["check-packages"]["steps"]
+    step = next((step for step in steps if step.get("name") == TEST_STEP), None)
+    assert step is not None, f"workflow step {TEST_STEP!r} not found in extension-package-check.yml"
+    return step
+
+
+def _tested_packages() -> list[Path]:
+    return sorted(path.parent for path in REPO_ROOT.glob("examples/deerflow-extension-*/tests"))
+
+
+@pytest.mark.parametrize("event", ["push", "pull_request"])
+def test_contract_and_example_changes_trigger_the_package_check(event: str) -> None:
+    paths = _workflow()["on"][event]["paths"]
+    assert "examples/deerflow-extension-*/**" in paths
+    assert "backend/packages/extension-api/**" in paths
+
+
+def test_package_tests_run_against_the_checkout_contract() -> None:
+    script = _test_step()["run"]
+    lines = [line.strip() for line in script.splitlines()]
+
+    assert "for package in examples/deerflow-extension-*/; do" in lines
+    assert '[ -d "${package}tests" ] || continue' in lines
+    install_contract = lines.index("uv pip install -e ../../backend/packages/extension-api")
+    install_package = lines.index('uv pip install -e ".[dev]"')
+    assert install_contract < install_package
+    for command in ("uv run --no-project pytest -q", "uv run --no-project ruff check .", "uv run --no-project ruff format --check ."):
+        assert lines.index(command) > install_package
+
+
+def test_every_example_with_tests_declares_the_dev_tools_ci_runs() -> None:
+    packages = _tested_packages()
+    assert packages, "the extension example ships package tests"
+    for package in packages:
+        project = tomllib.loads((package / "pyproject.toml").read_text(encoding="utf-8"))["project"]
+        dev = {Requirement(value).name for value in project.get("optional-dependencies", {}).get("dev", [])}
+        assert {"pytest", "ruff"} <= dev, package.name
diff --git a/examples/README.md b/examples/README.md
index c936b46a94..22d3e45296 100644
--- a/examples/README.md
+++ b/examples/README.md
@@ -20,7 +20,10 @@ Additional examples cover [text-list classification](deerflow-extension-jev-clas
    package, distribution and `deerflow.extensions` entry point. For a full-stack
    plugin, also choose its own namespace and browser module name.
 2. Follow the example's README to configure its dependencies and run its tests.
-   Keep package behavior tests alongside the extension.
+   Keep package behavior tests alongside the extension. For a bundled example
+   with a `tests/` directory, CI installs the package with its `dev` extra next
+   to this checkout's `deerflow-extension-api`, then runs `pytest`, `ruff check`
+   and `ruff format --check`.
 3. From the DeerFlow checkout root, prepare the backend environment with
    `make -C backend install`, then check the package:
 
diff --git a/examples/deerflow-extension-example/README.md b/examples/deerflow-extension-example/README.md
index cde734b95e..e0a22fb78b 100644
--- a/examples/deerflow-extension-example/README.md
+++ b/examples/deerflow-extension-example/README.md
@@ -4,14 +4,15 @@ For the shared edit → test → packaging check → install workflow, see the
 [existing-example guide](../README.md).
 
 This directory is a compact, standalone Python package showing five of the
-eight DeerFlow extension contribution kinds: middleware, task lifecycle,
+nine DeerFlow extension contribution kinds: middleware, task lifecycle,
 system-model observer, service, and router. It depends on the public
 `deerflow-extension-api` contract and never imports `deerflow.*` or `app.*`.
 
 It does not register an agent-assembly observer, a context-compaction observer,
-or a full-stack plugin. The observers are covered in the
+a knowledge provider, or a full-stack plugin. The observers are covered in the
 [Lifecycle and Observers](../../frontend/src/content/en/harness/extensions/observers.mdx)
-guide, and [`deerflow-extension-bookmarks`](../deerflow-extension-bookmarks/)
+guide, [`deerflow-extension-knowledge`](../deerflow-extension-knowledge/) shows
+a knowledge provider, and [`deerflow-extension-bookmarks`](../deerflow-extension-bookmarks/)
 shows a plugin.
 
 The contract package intentionally has no framework dependencies. An extension
@@ -92,7 +93,9 @@ uv run --no-project ruff format --check .
 ```
 
 The tests use only the public contract plus this package's declared dependencies;
-the DeerFlow harness and Gateway application are not imported.
+the DeerFlow harness and Gateway application are not imported. CI runs these
+commands whenever this package or `deerflow-extension-api` changes, so a contract
+addition that the test registry does not implement fails the pull request.
 
 ## Install and load it in DeerFlow
 
diff --git a/examples/deerflow-extension-example/tests/test_plugin.py b/examples/deerflow-extension-example/tests/test_plugin.py
index ac007b0334..d13935863f 100644
--- a/examples/deerflow-extension-example/tests/test_plugin.py
+++ b/examples/deerflow-extension-example/tests/test_plugin.py
@@ -26,10 +26,9 @@ from deerflow_extension_example import install
 
 
 class FakeRegistry:
-    def plugin(self, contribution: Any) -> bool:
-        return False
-
     def __init__(self) -> None:
+        self.plugins: list[Any] = []
+        self.knowledge_providers: list[tuple[str, Any]] = []
         self.middleware_contributors: list[Any] = []
         self.task_lifecycle_contributors: list[Any] = []
         self.system_model_observers: list[Any] = []
@@ -38,6 +37,14 @@ class FakeRegistry:
         self.services: list[Any] = []
         self.contributed_routers: list[Any] = []
 
+    def plugin(self, contribution: Any) -> bool:
+        self.plugins.append(contribution)
+        return True
+
+    def knowledge_provider(self, name: str, provider: Any) -> bool:
+        self.knowledge_providers.append((name, provider))
+        return True
+
     def middlewares(self, contributor: Any) -> None:
         self.middleware_contributors.append(contributor)
 
@@ -84,6 +91,8 @@ def test_install_registers_the_five_demonstrated_contribution_kinds() -> None:
     # The README names these as not demonstrated here.
     assert registry.agent_assembly_observers == []
     assert registry.context_compaction_observers == []
+    assert registry.knowledge_providers == []
+    assert registry.plugins == []
     assert [route.path for route in registry.contributed_routers[0].routes] == ["/api/extension-example/stats"]
     assert install.__deerflow_api__ == "0.2.0"
     assert install.__deerflow_name__ == "example"