fix(cli): fzd and fz design passed args core fzd() rejects

fzd_main() and the `fz design` subcommand called core fzd() with
`results_dir=` and the algorithm options spread as `**kwargs`, but fzd()
accepts `analysis_dir` and `algorithm_options`. Every CLI invocation therefore
failed immediately with:

    TypeError: fzd() got an unexpected keyword argument 'results_dir'

Map both call sites to the correct parameters (results_dir -> analysis_dir,
options dict -> algorithm_options=).

The break shipped because fzd CLI execution had no test coverage — test_fzd.py
exercised only the Python API. Add two regression tests (the standalone `fzd`
entry point and the `fz design` subcommand) that run a real design with
--results_dir and --options; verified they fail without the fix with the exact
TypeError above.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: yannrichet

NEWS.md

@@ -24,6 +24,16 @@
 - `fzd` docstring corrected: `analysis_dir` defaults to `"analysis"` (the CLI uses
   `results_fzd`).
 
+### fzd CLI execution fix
+
+- The `fzd` command and the `fz design` subcommand were unusable: both passed
+  `results_dir=` and the algorithm options as `**kwargs` to core `fzd()`, which accepts
+  `analysis_dir` and `algorithm_options` instead — so every invocation failed immediately
+  with `TypeError: fzd() got an unexpected keyword argument 'results_dir'`. Both call
+  sites now map to the correct parameters. Added regression tests that exercise the `fzd`
+  CLI and the `fz design` subcommand (only the Python API was covered before, which is why
+  this shipped).
+
 ### CLI hardening for scripting and AI agents
 
 - Log messages (`FZ_LOG_LEVEL`) and progress output now go to **stderr** instead of

fz/cli.py

@@ -672,9 +672,9 @@ def fzd_main():
             model,
             args.output_expression,
             args.algorithm,
-            results_dir=args.results_dir,
             calculators=calculators,
-            **(algo_options if isinstance(algo_options, dict) else {})
+            algorithm_options=(algo_options if isinstance(algo_options, dict) else {}),
+            analysis_dir=args.results_dir,
         )
 
         # Print summary
@@ -853,9 +853,9 @@ def main():
                 model,
                 args.output_expression,
                 args.algorithm,
-                results_dir=args.results_dir,
                 calculators=calculators,
-                **algo_options
+                algorithm_options=algo_options,
+                analysis_dir=args.results_dir,
             )
 
             # Print summary

tests/test_fzd.py

@@ -2,7 +2,9 @@
 Tests for fzd (iterative design of experiments with algorithms)
 """
 
+import json
 import os
+import subprocess
 import sys
 import tempfile
 import shutil
@@ -148,6 +150,60 @@ def test_fzd_randomsampling(self, simple_model):
         assert "result" in result["XY"].columns  # output_expression as column name
         assert algo_path in result["algorithm"]  # algorithm field contains the path
 
+    def test_fzd_cli_runs(self, simple_model, monkeypatch):
+        """Regression: the `fzd` CLI must actually run a design.
+
+        fzd_main() called core fzd() with results_dir=/**options, but fzd()
+        accepts analysis_dir/algorithm_options — so every invocation raised
+        TypeError ('unexpected keyword argument results_dir'). No fzd CLI
+        execution test existed, so the break shipped. This covers entry point 1
+        (the standalone `fzd` command, fz.cli:fzd_main).
+        """
+        if shutil.which("bc") is None:
+            pytest.skip("bc command not available")
+
+        input_dir, model = simple_model
+        algo_path = str(Path(__file__).parent.parent / "examples" / "algorithms" / "randomsampling.py")
+        analysis_dir = Path(input_dir).parent / "fzd_cli_out"
+
+        from fz import cli
+        monkeypatch.setattr(sys, "argv", [
+            "fzd",
+            "-i", str(input_dir),
+            "-m", json.dumps(model),
+            "-v", json.dumps({"x": "[0;1]", "y": "[0;1]"}),
+            "-e", "result",
+            "-a", algo_path,
+            "-o", json.dumps({"nvalues": 3, "seed": 42}),  # exercises --options
+            "-r", str(analysis_dir),                        # exercises --results_dir
+        ])
+        rc = cli.fzd_main()
+        assert rc == 0
+
+    def test_fz_design_cli_runs(self, simple_model):
+        """Regression: the `fz design` subcommand must run too (entry point 2).
+
+        Same bug as test_fzd_cli_runs, separate call site in fz.cli:main.
+        """
+        if shutil.which("bc") is None:
+            pytest.skip("bc command not available")
+
+        input_dir, model = simple_model
+        algo_path = str(Path(__file__).parent.parent / "examples" / "algorithms" / "randomsampling.py")
+        analysis_dir = Path(input_dir).parent / "design_cli_out"
+
+        result = subprocess.run([
+            sys.executable, "-m", "fz.cli", "design",
+            "-i", str(input_dir),
+            "-m", json.dumps(model),
+            "-v", json.dumps({"x": "[0;1]", "y": "[0;1]"}),
+            "-e", "result",
+            "-a", algo_path,
+            "-o", json.dumps({"nvalues": 3, "seed": 42}),
+            "-r", str(analysis_dir),
+        ], capture_output=True, text=True)
+        assert result.returncode == 0, f"stdout:\n{result.stdout}\nstderr:\n{result.stderr}"
+
     # Removed test_fzd_requires_pandas - pandas is now a required dependency
 
     def test_fzd_returns_dataframe(self, simple_model):