Add CI workflow and strengthen contributing guidelines

- Run pytest on Python 3.10/3.11/3.12 on every push and PR
- Require tests for all PRs in CONTRIBUTING section of README

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: ChengaDev

.github/workflows/ci.yml

@@ -0,0 +1,29 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+jobs:
+  test:
+    name: Tests (Python ${{ matrix.python-version }})
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version: ["3.10", "3.11", "3.12"]
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-python@v5
+        with:
+          python-version: ${{ matrix.python-version }}
+          cache: pip
+
+      - name: Install dependencies
+        run: pip install -e ".[all-providers]"
+
+      - name: Run tests
+        run: pytest tests/ -v --tb=short

README.md

@@ -593,14 +593,21 @@ Environment variables: `ANTHROPIC_API_KEY`, `OPENAI_API_KEY`, `GOOGLE_API_KEY`,
 
 ## Contributing
 
-Contributions are welcome. Some good first areas:
+Contributions are welcome. Please open an issue first for anything beyond a small bug fix so we can align on direction before you invest time in a PR.
+
+### Requirements for every PR
+
+- **Tests are mandatory.** Every change to behaviour must include tests. PRs without tests covering the new or changed code will not be merged.
+- All existing tests must continue to pass (`pytest tests/ -v`).
+- Keep new dependencies minimal — ask in an issue if you're unsure.
+
+### Good first areas
 
 - **New MCP servers** — Jira, PagerDuty, Datadog log fetcher, `kubectl` live pod state
 - **New log patterns** — add to `_PATTERNS` in `log_analyzer.py` with a matching fixture and test
-- **GitHub Actions step summary** — write the RCA to `$GITHUB_STEP_SUMMARY`
 - **Streaming output** — stream Claude's reasoning in real time
 
-To add a new issue pattern:
+### Adding a new log pattern
 
 1. Add a `(regex, IssueKind, group_index)` entry to `_PATTERNS` in `mcp_tools/log_analyzer.py`
 2. Add a realistic fixture log to `tests/fixtures/`