fix(a2a): derive agent card version from package metadata

tests/test_a2a.py

@@ -100,6 +100,18 @@ def test_agent_card_alias_is_published(monkeypatch, service, settings) -> None:
     assert payload["skills"][0]["inputModes"] == ["text/plain"]
 
 
+def test_agent_card_version_matches_package_metadata(monkeypatch, service, settings) -> None:
+    # The agent card version must track the package version instead of a
+    # hard-coded literal that can drift from pyproject.toml (issue #88).
+    from vesper import __version__
+
+    response = asyncio.run(_request(_app(monkeypatch, service, settings), "GET", "/.well-known/agent-card.json"))
+
+    assert response.status_code == 200
+    payload = response.json()
+    assert payload["version"] == __version__
+
+
 def test_agent_json_alias_is_removed(monkeypatch, service, settings) -> None:
     response = asyncio.run(_request(_app(monkeypatch, service, settings), "GET", "/.well-known/agent.json"))
 

vesper/__init__.py

@@ -1,5 +1,14 @@
 """Vesper package."""
 
+from importlib.metadata import PackageNotFoundError, version as _pkg_version
+
 __all__ = ["__version__"]
 
-__version__ = "0.1.0"
+# Single source of truth is pyproject.toml. Read the installed distribution
+# metadata so the version can't drift from the packaging metadata. Fall back to
+# the literal for editable/source runs where the distribution is not installed
+# (issue #88).
+try:
+    __version__ = _pkg_version("vesper")
+except PackageNotFoundError:  # pragma: no cover - editable/source tree runs
+    __version__ = "0.1.0"

vesper/a2a.py

@@ -412,7 +412,7 @@ def create_http_app(*, include_a2a: bool = False, include_mcp: bool = False) ->
         mcp_app = mcp_server.streamable_http_app()
         mcp_endpoint = cast(Route, mcp_app.routes[0]).endpoint
 
-    app = FastAPI(title="Vesper", version="0.1.0", lifespan=_create_lifespan(mcp_server.session_manager if mcp_server else None))
+    app = FastAPI(title="Vesper", version=__version__, lifespan=_create_lifespan(mcp_server.session_manager if mcp_server else None))
 
     @app.get("/healthz")
     async def healthz() -> dict[str, str]: