diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 773c79d..4bdfb7f 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -1,50 +1,139 @@
 # Contributing to GCode
 
+Thanks for contributing! GCode is community-built, and bug reports, docs,
+tests, and features are all welcome.
+
+- **First-time contributor?** Start with a
+  [good first issue](https://github.com/shauryagangrade/GCode/labels/good%20first%20issue).
+- Looking for more? Browse the
+  [help wanted](https://github.com/shauryagangrade/GCode/labels/help%20wanted) issues.
+- Open an issue before starting large work so maintainers can steer scope.
+
 ---
 
 ## Quick Setup
 
+GCode uses [uv](https://docs.astral.sh/uv/) for dependency management and
+development. Install uv first:
+
+```bash
+curl -LsSf https://astral.sh/uv/install.sh | sh
+```
+
+Then clone and set up:
+
 ```bash
 git clone https://github.com/shauryagangrade/GCode.git
 cd GCode
-pip install -e .
+uv sync --extra dev
 mkdir -p ~/.gcode && cp .env.example ~/.gcode/.env
-gcode
 ```
 
-You will need an OpenRouter API key. Copy the `.env.example` file to
-`~/.gcode/.env` and fill in your `OPENROUTER_API_KEY`.
+Fill in your `OPENROUTER_API_KEY` in `~/.gcode/.env` (see
+[README setup](README.md#setup)), then run:
+
+```bash
+uv run gcode
+```
+
+> **Windows?** See [docs/windows.md](docs/windows.md) for native, WSL2, and
+> Git Bash instructions and known limitations.
+
+---
+
+## Local checks
+
+CI runs these exact commands (see `.github/workflows/ci.yml`). Run them all
+locally before pushing:
+
+```bash
+uv run ruff check .                 # lint
+uv run ruff format --check .        # formatting
+uv run mypy gcode                   # type check
+uv run bandit -q -r gcode/ -c pyproject.toml   # security scan
+uv run python -m compileall -q gcode demo      # compile check
+uv run pytest                       # test suite
+```
+
+The test suite runs against Python 3.10–3.13 in CI, so the same code should
+pass on any of those versions locally.
 
 ---
 
 ## How to Contribute
 
 ### Reporting Bugs
-Open an issue using the [bug report template](.github/ISSUE_TEMPLATE/bug_report.md). Include steps to reproduce, expected vs actual behavior, and environment info.
+
+Open an issue using the
+[bug report template](.github/ISSUE_TEMPLATE/bug_report.yml). Include steps
+to reproduce, expected vs actual behavior, and environment info.
 
 ### Requesting Features
-Open an issue using the [feature request template](.github/ISSUE_TEMPLATE/feature_request.md).
+
+Open an issue using the
+[feature request template](.github/ISSUE_TEMPLATE/feature_request.yml).
 
 ### Submitting a PR
 
 1. Fork the repo and create a branch: `git checkout -b feat/your-feature`
 2. Make your changes
-3. Verify: `pytest` — must pass clean
-4. Open a PR against `main`
+3. Run the [local checks](#local-checks) — all must pass
+4. Open a PR against `main` and describe *why*, not just *what*
 
 ---
 
-## Good First Issues
-
-Look for issues labeled [`good first issue`](https://github.com/shauryagangrade/GCode/labels/good%20first%20issue).
+## Adding a new tool or slash command
+
+GCode exposes two kinds of commands:
+
+- **Agent tools** — what the model can call (read/write files, run bash,
+  git operations).
+- **Slash commands** — what the *user* types in the REPL (`/help`, `/models`,
+  `/status`, ...).
+
+### Adding an agent tool
+
+Tools live in `gcode/tools.py`. Each is a function decorated with
+`@tool` from `langchain.tools`, so the model receives a clean schema and
+description.
+
+1. Write the function in `gcode/tools.py` with a docstring that describes
+   when to use it and its arguments (the docstring becomes the tool schema).
+2. Add it to the `ALL_TOOLS` list (which also sets the order tools are
+   offered to the model).
+3. Add it to `TOOL_MAP` — the `name -> tool` dict used to dispatch model
+   calls: `TOOL_MAP = {t.name: t for t in ALL_TOOLS}`.
+4. Add a unit test in `tests/` (see `tests/test_tools.py` for the pattern).
+5. Run `uv run pytest` and the lint checks above.
+
+### Adding a slash command
+
+Slash commands are handled in `gcode/cli.py` inside the `main()` REPL loop.
+The interactive menu is driven by `_SLASH_COMMANDS` in `gcode/ui.py`, and
+`/help` text lives in `_print_help` in `gcode/cli.py`.
+
+1. Add the command handler in `gcode/cli.py` — a `_cmd_*` function plus a
+   `elif cmd == "..."` branch in `main()`.
+2. Add the command to `_SLASH_COMMANDS` in `gcode/ui.py` as a
+   `("/command", "one-line description")` tuple so it appears in the
+   interactive `/` menu.
+3. Add it to `_print_help` in `gcode/cli.py` under the right group
+   (General / Model / Session / Git).
+4. Update the README's [Commands](README.md#use) list.
+5. Add a unit test where the command has testable behavior (see
+   `tests/test_cli.py`); commands that only render UI may be covered by
+   `tests/test_ui.py`.
+6. Run `uv run pytest` and the lint checks above.
 
 ---
 
 ## Code Style
 
-- Follow PEP 8 styling guidelines.
+- Follow the lint rules enforced by `ruff` (targets Python 3.10+, line
+  length 100).
 - Write clean, readable code with descriptive variable names.
-- Ensure all tests pass before opening a PR.
+- Add type annotations — `mypy gcode` must stay green.
+- Keep changes narrow: one PR per change.
 
 ---
 
@@ -52,19 +141,21 @@ Look for issues labeled [`good first issue`](https://github.com/shauryagangrade/
 
 - One PR per change — keep scope tight
 - PR description must explain *why*, not just *what*
-- Ensure any new tools or CLI commands are documented.
-- AI-assisted code is welcome — provided you have reviewed and tested the output.
+- Ensure any new tools or CLI commands are documented (this checklist above)
+- AI-assisted code is welcome — provided you have reviewed and tested the output
 
 ---
 
 ## Commit Style
 
 [Conventional Commits](https://www.conventionalcommits.org/):
+
 ```
 feat: add dark mode toggle
 fix: correct timezone offset in tournament dates
 docs: update quick start steps
 ```
+
 Types: `feat | fix | docs | style | refactor | perf | test | ci | chore`
 
 ---