build: derive package version from git via setuptools-scm

Replace hatchling and the static version with setuptools + setuptools-scm,
following Kaya's pre-uv packaging setup: dynamic version, generated
_version.py, and release/* tag prefix. The Docker builder now includes git
and the .git directory so the image is versioned from the checkout. CI
checks out full history and tags for the tag-triggered builds.

.dockerignore

@@ -1,4 +1,3 @@
-.git/
 .gitignore
 .venv/
 __pycache__/
@@ -15,3 +14,8 @@ Dockerfile
 !README.md
 xmcp.yml
 xmcp.example.yml
+
+# Generated at build time
+src/xmcp/_version.py
+*.egg-info/
+dist/

.gitea/workflows/build.yaml

@@ -11,6 +11,10 @@ jobs:
     steps:
       - name: Checkout sources
         uses: actions/checkout@v6
+        with:
+          # setuptools-scm needs tags and history to derive the package version.
+          fetch-depth: 0
+          fetch-tags: true
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
       - name: Login to Gitea container registry

.gitignore

@@ -10,3 +10,9 @@ xmcp.yml
 xmcp.local.yml
 .env
 .env.*
+
+# Generated version metadata and build artifacts
+src/xmcp/_version.py
+*.egg-info/
+build/
+dist/

Dockerfile

@@ -6,6 +6,9 @@
 FROM python:3.14-alpine3.24 AS builder
 COPY --from=ghcr.io/astral-sh/uv:0.13.1 /uv /uvx /bin/
 
+# setuptools-scm derives the package version from git history and tags.
+RUN apk add --no-cache git
+
 ENV UV_COMPILE_BYTECODE=1 \
     UV_LINK_MODE=copy \
     UV_PYTHON_DOWNLOADS=never
@@ -17,9 +20,11 @@ COPY pyproject.toml uv.lock .python-version ./
 RUN --mount=type=cache,target=/root/.cache/uv \
     uv sync --frozen --no-dev --no-install-project
 
-# Then install the project itself as a regular wheel.
+# Then install the project itself as a regular wheel. The git metadata is
+# required by setuptools-scm to derive the package version.
 COPY README.md ./
 COPY src ./src
+COPY .git ./.git
 RUN --mount=type=cache,target=/root/.cache/uv \
     uv sync --frozen --no-dev --no-editable
 

README.md

@@ -220,6 +220,11 @@ git push origin release/0.2.0
 This publishes `gitea.woggioni.net/woggioni/xmcp:0.2.0` and
 `gitea.woggioni.net/woggioni/xmcp:latest`.
 
+The Python package version is derived from the pushed `release/*` tag with
+[setuptools-scm](https://setuptools-scm.readthedocs.io): `release/0.2.0`
+produces package version `0.2.0`. Builds from untagged commits carry a PEP 440
+development version (for example `0.2.1.dev3+gabc1234`).
+
 ## Project layout
 
 ```

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "xmcp"
-version = "0.2.0"
+dynamic = ["version"]
 description = "MCP server generated from an OpenAPI specification, built with FastMCP"
 readme = "README.md"
 requires-python = ">=3.14"
@@ -14,8 +14,14 @@ dependencies = [
 xmcp = "xmcp.server:main"
 
 [build-system]
-requires = ["hatchling"]
+requires = ["setuptools>=61.0", "setuptools-scm>=8"]
-build-backend = "hatchling.build"
+build-backend = "setuptools.build_meta"
 
-[tool.hatch.build.targets.wheel]
+[tool.setuptools.packages.find]
-packages = ["src/xmcp"]
+where = ["src"]
+
+[tool.setuptools_scm]
+version_file = "src/xmcp/_version.py"
+
+[tool.setuptools_scm.tag]
+prefix = "release/"

src/xmcp/__init__.py

@@ -1,3 +1,5 @@
 """xmcp: an MCP server generated from an OpenAPI specification with FastMCP."""
 
-__version__ = "0.2.0"
+from ._version import __version__
+
+__all__ = ["__version__"]

uv.lock

@@ -1231,7 +1231,6 @@ wheels = [
 
 [[package]]
 name = "xmcp"
-version = "0.2.0"
 source = { editable = "." }
 dependencies = [
     { name = "fastmcp" },