diff --git a/.github/copilot-instructions.md b/.github/copilot-instructions.md
new file mode 100644
index 00000000..8d7baa2f
--- /dev/null
+++ b/.github/copilot-instructions.md
@@ -0,0 +1,12 @@
+# GitHub Copilot Custom Instructions for Cachier
+
+- Cachier is a Python package providing persistent, stale-free memoization decorators for Python functions, supporting local (pickle), cross-machine (MongoDB), and in-memory caching backends.
+- Always refer to the main decorator as `@cachier`, and note that it can be configured via parameters such as `stale_after`, `backend`, `mongetter`, `cache_dir`, `pickle_reload`, `separate_files`, `wait_for_calc_timeout`, and `allow_none`.
+- Arguments to cached functions must be hashable; custom hash functions can be provided via the `hash_func` parameter for unhashable arguments.
+- The default backend is pickle-based, storing cache files in `~/.cachier/` unless otherwise specified. MongoDB and memory backends are also supported.
+- Cachier is thread-safe and supports per-function cache clearing via the `clear_cache()` method on decorated functions.
+- Global configuration is possible via `set_default_params` and `enable_caching`/`disable_caching` functions.
+- When reviewing code, ensure new features or bugfixes maintain compatibility with Python 3.9+, preserve thread safety, and follow the numpy docstring conventions for documentation.
+- Tests are located in the `tests/` directory and should be run with `pytest`. MongoDB-related tests require either a mocked or live MongoDB instance.
+- When discussing or generating code, prefer concise, readable, and well-documented Python code, and follow the established conventions in the codebase and README.
+- For documentation, follow numpy docstring conventions and validate changes to `README.rst` with `python setup.py checkdocs`.
diff --git a/.github/workflows/safety.yml b/.github/workflows/safety.yml
deleted file mode 100644
index 50f38831..00000000
--- a/.github/workflows/safety.yml
+++ /dev/null
@@ -1,27 +0,0 @@
-name: Check safety
-
-on:
-  pull_request:
-    branches: [master]
-  push:
-    branches: [master]
-
-concurrency:
-  group: ${{ github.workflow }}-${{ github.ref }}-${{ github.head_ref }}
-  cancel-in-progress: ${{ github.ref != 'refs/heads/master' }}
-
-jobs:
-  safety:
-    runs-on: "ubuntu-latest"
-    environment: safety_check
-    steps:
-      - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
-      - name: create requirements.txt
-        run: |
-          pip install uv
-          uv pip compile pyproject.toml -o requirements.txt
-      - name: Security vulnerabilities scan
-        uses: shaypal5/python-safety-checker@v1.0.6
-        with:
-          scan_requirements_file_only: "true"
diff --git a/README.rst b/README.rst
index fc9c8e90..6daa1e55 100644
--- a/README.rst
+++ b/README.rst
@@ -44,7 +44,7 @@ Features
 ========
 
 * Pure Python.
-* Compatible with Python 3.8+ (Python 2.7 was discontinued in version 1.2.8).
+* Compatible with Python 3.9+ (Python 2.7 was discontinued in version 1.2.8).
 * Supported and `tested on Linux, OS X and Windows <https://travis-ci.org/shaypal5/cachier>`_.
 * A simple interface.
 * Defining "shelf life" for cached values.