diff --git a/.github/scripts/check_sdk_api_breakage.py b/.github/scripts/check_sdk_api_breakage.py
new file mode 100755
index 0000000000..a58a942428
--- /dev/null
+++ b/.github/scripts/check_sdk_api_breakage.py
@@ -0,0 +1,161 @@
+#!/usr/bin/env python3
+import json
+import os
+import sys
+import tomllib
+import urllib.request
+from collections.abc import Iterable
+
+
+def read_version_from_pyproject(path: str) -> str:
+    with open(path, "rb") as f:
+        data = tomllib.load(f)
+    proj = data.get("project", {})
+    v = proj.get("version")
+    if not v:
+        raise SystemExit("Could not read version from pyproject")
+    return str(v)
+
+
+def parse_version(v: str) -> tuple[int, int, int]:
+    parts = v.split(".")
+    nums: list[int] = []
+    for p in parts[:3]:
+        n = ""
+        for ch in p:
+            if ch.isdigit():
+                n += ch
+            else:
+                break
+        nums.append(int(n or 0))
+    while len(nums) < 3:
+        nums.append(0)
+    return tuple(nums)  # type: ignore[return-value]
+
+
+def get_prev_pypi_version(pkg: str, current: str | None) -> str | None:
+    try:
+        with urllib.request.urlopen(
+            f"https://pypi.org/pypi/{pkg}/json", timeout=10
+        ) as r:
+            meta = json.load(r)
+    except Exception:
+        return None
+    releases = list(meta.get("releases", {}).keys())
+    if not releases:
+        return None
+    if current is None:
+        # Pick the highest lexicographically by parsed tuple
+        releases_sorted = sorted(releases, key=lambda s: parse_version(s), reverse=True)
+        return releases_sorted[0]
+    cur_t = parse_version(current)
+    older = [rv for rv in releases if parse_version(rv) < cur_t]
+    if not older:
+        return None
+    return sorted(older, key=lambda s: parse_version(s), reverse=True)[0]
+
+
+def ensure_griffe() -> None:
+    try:
+        import griffe  # noqa: F401
+    except Exception:
+        sys.stderr.write("griffe not installed; please install griffe[pypi]\n")
+        raise
+
+
+def collect_breakages(objs: Iterable[tuple[object, object]]) -> list:
+    import griffe
+    from griffe import ExplanationStyle
+
+    breakages = []
+    for old, new in objs:
+        for br in griffe.find_breaking_changes(old, new):
+            obj = getattr(br, "obj", None)
+            is_public = getattr(obj, "is_public", True)
+            if is_public:
+                print(br.explain(style=ExplanationStyle.GITHUB))
+                breakages.append(br)
+    return breakages
+
+
+def main() -> int:
+    ensure_griffe()
+    import griffe
+
+    repo_root = os.getcwd()
+    sdk_pkg = "openhands.sdk"
+    current_pyproj = os.path.join(repo_root, "openhands-sdk", "pyproject.toml")
+    new_version = read_version_from_pyproject(current_pyproj)
+
+    include = os.environ.get("SDK_INCLUDE_PATHS", sdk_pkg).split(",")
+    include = [p.strip() for p in include if p.strip()]
+
+    prev = get_prev_pypi_version("openhands-sdk", new_version)
+    if not prev:
+        print(
+            "::warning title=SDK API::No previous openhands-sdk release found; "
+            "skipping breakage check"
+        )
+        return 0
+
+    # Load currently checked-out code
+    new_root = griffe.load(
+        sdk_pkg, search_paths=[os.path.join(repo_root, "openhands-sdk")]
+    )
+
+    # Load previous from PyPI
+    try:
+        old_root = griffe.load_pypi("openhands-sdk", version=prev)
+    except Exception as e:
+        print(f"::warning title=SDK API::Failed to load previous from PyPI: {e}")
+        return 0
+
+    def resolve(root, dotted: str):
+        # Try absolute path first
+        try:
+            return root[dotted]
+        except Exception:
+            pass
+        # Try relative to sdk_pkg
+        rel = dotted
+        if dotted.startswith(sdk_pkg + "."):
+            rel = dotted[len(sdk_pkg) + 1 :]
+        obj = root
+        for part in rel.split("."):
+            obj = obj[part]
+        return obj
+
+    pairs = []
+    for path in include:
+        try:
+            old_obj = resolve(old_root, path)
+            new_obj = resolve(new_root, path)
+            pairs.append((old_obj, new_obj))
+        except Exception as e:
+            print(f"::warning title=SDK API::Path {path} not found: {e}")
+    if not pairs:
+        print("::warning title=SDK API::No valid include paths, skipping")
+        return 0
+
+    brs = collect_breakages(pairs)
+    if not brs:
+        print("No SDK breaking changes detected")
+        return 0
+
+    # Enforce minor bump policy
+    old_major, old_minor, _ = parse_version(prev)
+    new_major, new_minor, _ = parse_version(new_version)
+    ok = (new_major == old_major) and (new_minor > old_minor)
+    if not ok:
+        print(
+            f"::error title=SDK SemVer::Breaking changes detected; "
+            f"require minor version bump from {old_major}.{old_minor}.x, "
+            f"but new is {new_version}"
+        )
+        return 1
+    print("SDK breaking changes detected and minor bump policy satisfied")
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())
diff --git a/.github/workflows/api-breakage.yml b/.github/workflows/api-breakage.yml
new file mode 100644
index 0000000000..0f5186585b
--- /dev/null
+++ b/.github/workflows/api-breakage.yml
@@ -0,0 +1,36 @@
+---
+name: API breakage checks
+
+on:
+    pull_request:
+        branches: [main, release/*]
+
+jobs:
+    sdk-api:
+        name: SDK programmatic API (Griffe)
+        runs-on: ubuntu-latest
+        steps:
+            - name: Checkout
+              uses: actions/checkout@v5
+              with:
+                  fetch-depth: 0
+            - name: Install uv
+              uses: astral-sh/setup-uv@v7
+              with:
+                  enable-cache: true
+            - name: Install workspace deps (dev)
+              run: uv sync --frozen --group dev
+            - name: Ensure griffe is available
+              run: |
+                  uv run python - << 'PY'
+                  try:
+                      import griffe  # noqa: F401
+                  except Exception:
+                      import subprocess
+                      subprocess.check_call(["uv", "pip", "install", "griffe[pypi]"])
+                  PY
+            - name: Run SDK API breakage check
+              env:
+                  SDK_INCLUDE_PATHS: openhands.sdk
+              run: |
+                  uv run python .github/scripts/check_sdk_api_breakage.py