diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..ee7d2ff
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,49 @@
+name: CI
+
+on:
+  push:
+    branches: ["**"]
+  pull_request:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  typecheck:
+    name: Typecheck
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install uv
+        uses: astral-sh/setup-uv@v5
+        with:
+          enable-cache: true
+      - name: Install dependencies
+        run: uv sync
+      - name: Mypy
+        run: uv run --with mypy mypy teslemetry_stream
+
+  test:
+    name: Test (Python ${{ matrix.python-version }})
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install uv
+        uses: astral-sh/setup-uv@v5
+        with:
+          enable-cache: true
+      - name: Set up Python ${{ matrix.python-version }}
+        run: uv python install ${{ matrix.python-version }}
+      - name: Install dependencies
+        run: uv sync --python ${{ matrix.python-version }}
+      - name: Run tests
+        run: |
+          for f in tests/test_*.py; do
+            echo "Running $f"
+            uv run python "$f"
+          done
diff --git a/AGENTS.md b/AGENTS.md
new file mode 100644
index 0000000..414df99
--- /dev/null
+++ b/AGENTS.md
@@ -0,0 +1,15 @@
+# Project agent memory
+
+This file is the project's committed home for project-intrinsic agent knowledge: build, test, release, architecture, and sharp-edge notes that should travel with the code.
+
+- Add durable project-specific notes here as they are discovered through real work.
+- CI runs on push/PR: `.github/workflows/ci.yml`. Uses `uv` (see `uv.lock`).
+- `tests/` files are plain scripts (`if __name__ == "__main__"`), not pytest-based - pytest would collect zero tests here. Run each directly, e.g. `uv run python tests/test_field_type_coercion.py`.
+- `pyproject.toml` has a `[tool.mypy]` config but no dev-dependency group declares mypy, so `uv sync` alone won't install it. CI installs it ephemerally via `uv run --with mypy mypy teslemetry_stream`.
+
+## Maintaining this file
+
+Keep this file for knowledge useful to almost every future agent session in this project.
+Do not repeat what the codebase already shows; point to the authoritative file or command instead.
+Prefer rewriting or pruning existing entries over appending new ones.
+When updating this file, preserve this bar for all agents and keep entries concise.