diff --git a/ocp_tool/__main__.py b/ocp_tool/__main__.py
new file mode 100644
index 0000000..8305131
--- /dev/null
+++ b/ocp_tool/__main__.py
@@ -0,0 +1,127 @@
+"""Entry point for running ocp-tool as a module: python3 -m ocp_tool [config.yaml]"""
+
+import sys
+import time
+from pathlib import Path
+
+from ocp_tool.config import load_config
+from ocp_tool.gaussian_grids import generate_gaussian_grid, read_fesom_grid_polygon
+from ocp_tool.lsm import process_land_sea_mask, create_slt_output_for_lpjg
+from ocp_tool.oasis_writer import write_oasis_grid_files, interpolate_vegin_data
+from ocp_tool.runoff import modify_runoff_map, modify_runoff_lsm
+from ocp_tool.plotting import plot_land_sea_mask, plot_runoff_maps
+from ocp_tool.co2_interpolation import interpolate_co2_to_icmgg
+from ocp_tool.field_interpolation import interpolate_2d_fields_to_icmgg
+from ocp_tool.create_outputdirs import create_outputdirs
+
+
+def run_ocp_tool(config):
+    """Main OCP-Tool processing pipeline."""
+    print("=" * 60)
+    print(" OCP-Tool: OpenIFS Coupling Preparation Tool")
+    print("=" * 60)
+    print(f"\nConfiguration:")
+    print(f"  Atmosphere: {config.atmosphere.truncation_type} T{config.atmosphere.resolution_list}")
+    print(f"  Ocean grid: {config.ocean.grid_name}")
+    print(f"  Ice cavities: {config.ocean.has_ice_cavities}")
+    print(f"  Experiment: {config.atmosphere.experiment_name}")
+
+    for resolution in config.atmosphere.resolution_list:
+        print(f"\n{'='*60}")
+        print(f" Processing resolution T{resolution}")
+        print(f"{'='*60}\n")
+
+        print("Step 0: Creating output directories...")
+        create_outputdirs(config, resolution)
+
+        print("Step 1: Generating Gaussian grid coordinates...")
+        grid = generate_gaussian_grid(config, resolution)
+
+        if config.ocean.grid_name != 'AMIP':
+            print("\nStep 2: Reading FESOM ocean grid (polygon method)...")
+            ocean_lsm = read_fesom_grid_polygon(config, grid, verbose=config.options.verbose)
+        else:
+            print("\nStep 2: Skipped reading FESOM mesh (AMIP mode)")
+            ocean_lsm = []
+
+        print("\nStep 3: Processing land-sea mask...")
+        lsm_data = process_land_sea_mask(config, grid, ocean_lsm, resolution)
+
+        print("\nStep 4: Writing OASIS grid/mask/area files...")
+        write_oasis_grid_files(config, grid, lsm_data, resolution, parallel=False)
+
+        print("\nStep 5: Interpolating vegetation and CO2 restart data...")
+        interpolate_vegin_data(config, grid)
+
+        print("\nStep 6: Creating land-sea mask plots...")
+        plot_land_sea_mask(config, grid, lsm_data, resolution)
+
+        print("\nStep 7: Interpolating 3D CO2 concentrations...")
+        icmgg_iniua_file = config.get_icmgg_iniua_file()
+        interpolate_co2_to_icmgg(
+            str(config.co2_grib_file),
+            str(icmgg_iniua_file),
+            output_file=str(icmgg_iniua_file),
+            use_dask=config.options.use_dask,
+            n_workers=config.options.parallel_workers
+        )
+
+        print("\nStep 8: Processing CO2 emissions data...")
+        icmgg_init_file = config.get_icmgg_output_file()
+        interpolate_2d_fields_to_icmgg(
+            str(config.co2_emissions_grib_file),
+            str(icmgg_init_file),
+            output_file=str(icmgg_init_file),
+            variable_name='lsm',
+            field_type='co2_emissions',
+            verbose=config.options.verbose
+        )
+
+        print("\nStep 9: Adding bare soil albedo fields...")
+        interpolate_2d_fields_to_icmgg(
+            str(config.albedo_file),
+            str(icmgg_init_file),
+            field_type='albedo',
+            verbose=config.options.verbose
+        )
+
+        if config.ocean.grid_name != 'AMIP':
+            print("\nStep 10: Modifying runoff maps...")
+            lons, lats = modify_runoff_map(config, resolution)
+
+            print("\nStep 11: Modifying runoff land-sea mask...")
+            modify_runoff_lsm(config, lons, lats)
+        else:
+            print("\nStep 10-11: Skipped runoff processing (AMIP mode)")
+
+        print("\nStep 12: Creating SLT output for LPJ-GUESS...")
+        create_slt_output_for_lpjg(config, resolution)
+
+    print("\n" + "=" * 60)
+    print(" OCP-Tool processing complete!")
+    print("=" * 60)
+
+
+def main():
+    """Main entry point."""
+    if len(sys.argv) > 1:
+        config_path = Path(sys.argv[1])
+    else:
+        config_path = Path('config.yaml')
+
+    if not config_path.exists():
+        print(f"Error: Configuration file not found: {config_path}")
+        print("Usage: python3 -m ocp_tool [config.yaml]")
+        sys.exit(1)
+
+    print(f"Loading configuration from: {config_path}")
+    config = load_config(config_path)
+
+    start_time = time.time()
+    run_ocp_tool(config)
+    elapsed_time = time.time() - start_time
+    print(f"\nTotal execution time: {elapsed_time:.2f} seconds")
+
+
+if __name__ == '__main__':
+    main()
diff --git a/pyproject.toml b/pyproject.toml
index be4c22d..51e1735 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -29,7 +29,9 @@ dependencies = [
     "eccodes",
     "matplotlib",
     "pandas",
+    "pyfesom2 @ git+https://github.com/FESOM/pyfesom2.git@feature/ascii-to-netcdf-performance-optimization",
     "pyyaml",
+    "shapely",
     "tqdm",
 ]
 dynamic = ["version"]