diff --git a/.github/workflows/smoke.yml b/.github/workflows/smoke.yml
new file mode 100644
index 0000000..48c2e96
--- /dev/null
+++ b/.github/workflows/smoke.yml
@@ -0,0 +1,63 @@
+name: smoke
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  smoke:
+    name: smoke (${{ matrix.os }}, py${{ matrix.python-version }})
+    runs-on: ${{ matrix.os }}
+    timeout-minutes: 15
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, windows-latest]
+        python-version: ["3.11", "3.12", "3.13"]
+
+    defaults:
+      run:
+        # bash on every runner, including Windows, so $GITHUB_ENV and the
+        # heredoc below behave identically across the matrix.
+        shell: bash
+        working-directory: mcp
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          python -m pip install -r requirements.txt
+
+      - name: Resolve the interpreter for smoke.py
+        # smoke.py spawns server.py as a stdio subprocess and picks the command
+        # with os.environ.get("PYTHON", HERE/".venv"/"bin"/"python"). CI never
+        # creates a .venv, and that fallback path is POSIX-only anyway, so both
+        # the Linux and the Windows legs export PYTHON explicitly. sys.executable
+        # is already the correct absolute path on either platform.
+        run: python -c "import sys; print('PYTHON=' + sys.executable)" >> "$GITHUB_ENV"
+
+      - name: Confirm the mcp cap holds
+        # Regression guard for the reason this workflow exists: mcp 2.0.0 removed
+        # mcp.server.fastmcp, which server.py imports.
+        run: |
+          python - <<'PY'
+          from importlib.metadata import version
+
+          import mcp.server.fastmcp  # noqa: F401
+
+          resolved = version("mcp")
+          print("resolved mcp version:", resolved)
+          major = int(resolved.split(".")[0])
+          assert major < 2, f"mcp {resolved} resolved, so the <2 cap is not holding"
+          PY
+
+      - name: Run smoke.py
+        run: python smoke.py
diff --git a/mcp/pyproject.toml b/mcp/pyproject.toml
index 26298c9..100d8f3 100644
--- a/mcp/pyproject.toml
+++ b/mcp/pyproject.toml
@@ -4,7 +4,7 @@ version = "1.3.0"
 description = "stdio MCP server backing the aura-orchestrator skill (On-Chain Lab creation + public or private/encrypted data-room uploads) — wraps Privy, on-chain OCL reads, Labs GraphQL, the x402 payment flow, S3 uploads, AES-256-GCM envelope crypto, ABI encoding and on-chain access conditions (OCL/V3 surface, oclId)."
 requires-python = ">=3.10"
 dependencies = [
-    "mcp>=1.2.0",
+    "mcp>=1.2.0,<2",
     "httpx>=0.27",
     "cryptography>=42",
     "eth-abi>=5",
diff --git a/mcp/requirements.txt b/mcp/requirements.txt
index c054039..66d36b1 100644
--- a/mcp/requirements.txt
+++ b/mcp/requirements.txt
@@ -1,4 +1,4 @@
-mcp>=1.2.0
+mcp>=1.2.0,<2
 httpx>=0.27
 cryptography>=42
 eth-abi>=5