feat: enable unauthenticated server startup with runtime OAuth and update CI/CD to append Docker pull instructions to release notes

src/strava_mcp_server/main.py

@@ -16,7 +16,6 @@ def validate_credentials() -> None:
     required = {
         "STRAVA_CLIENT_ID": os.getenv("STRAVA_CLIENT_ID"),
         "STRAVA_CLIENT_SECRET": os.getenv("STRAVA_CLIENT_SECRET"),
-        "STRAVA_REFRESH_TOKEN": os.getenv("STRAVA_REFRESH_TOKEN"),
     }
     missing = [k for k, v in required.items() if not v]
     if missing:
@@ -25,6 +24,10 @@ def validate_credentials() -> None:
             print(f"   - {key}")
         print("\nCopy .env.example to .env and fill in your Strava API credentials.")
         sys.exit(1)
+        
+    if not os.getenv("STRAVA_REFRESH_TOKEN"):
+        print("ℹ️ No STRAVA_REFRESH_TOKEN found. Server starting in unauthenticated mode.")
+        print("   Use the 'get_new_oauth_token' tool via MCP to authenticate.")
 
 
 def main() -> None:
@@ -39,6 +42,7 @@ def main() -> None:
 
     mcp = FastMCP(
         "Strava MCP Server",
+        instructions="Dates returned by this server are generally in ISO-8601 (UTC) or formatted as DD.MM.YYYY HH:MM. Always present dates, times, and durations to the user in a natural, human-readable format appropriate for their language.",
         host=host,
         port=port,
         streamable_http_path="/mcp",

src/strava_mcp_server/strava_client.py

@@ -36,6 +36,9 @@ class StravaClient:
 
     async def get_valid_token(self) -> str:
         """Returns a valid access token, refreshing it if necessary."""
+        if not self.refresh_token:
+            raise ValueError("No Strava refresh token found. Please run the 'get_new_oauth_token' MCP tool to authenticate first.")
+            
         if not self.access_token or time.time() > self.expires_at - 60:
             await self._refresh_access_token()
         return self.access_token