feat: smooth browser challenge harness runs

examples/agent_challenges/browser_click_challenge/README.md

@@ -25,6 +25,10 @@ builds the configured workflow server in the CLI process for each command and
 uses the copied workspace's durable store. It does not reuse in-memory source
 sessions across CLI invocations.
 
+Use `--workspace-template` and `--source-root` to run a same-shape challenge with
+a different prompt template or Python source root. Both default to the bundled
+browser-click example settings.
+
 Use `--start-server` when the trial should exercise the JSON-RPC server path.
 With `--start-server`, the harness starts:
 
@@ -47,6 +51,16 @@ uv run python examples/agent_challenges/browser_click_challenge/run_opencode_tri
   --trials 1
 ```
 
+Variant challenge example:
+
+```powershell
+uv run python examples/agent_challenges/browser_click_challenge/run_opencode_trials.py `
+  --workspace-template examples/agent_challenges/browser_click_challenge/workspace_template `
+  --source-root examples/browser_click_workflow `
+  --workspaces-dir examples/agent_challenges/browser_click_challenge/workspaces_alt `
+  --results-dir examples/agent_challenges/browser_click_challenge/results_alt
+```
+
 Results are written to:
 
 ```text

examples/agent_challenges/browser_click_challenge/run_opencode_trials.py

@@ -235,6 +235,13 @@ def wf_command_prefix_for_config(config_path: Path) -> str:
     return f"uv run wf --config {path_arg} --local"
 
 
+def _display_path(path: Path) -> str:
+    try:
+        return path.resolve().relative_to(ROOT.resolve()).as_posix()
+    except ValueError:
+        return str(path.resolve())
+
+
 def stop_server(process: subprocess.Popen[str]) -> None:
     if process.poll() is not None:
         return
@@ -360,6 +367,18 @@ def main(argv: list[str] | None = None) -> int:
     parser.add_argument("--prompt", type=Path, default=DEFAULT_PROMPT)
     parser.add_argument("--results-dir", type=Path, default=DEFAULT_RESULTS_DIR)
     parser.add_argument("--workspaces-dir", type=Path, default=DEFAULT_WORKSPACES_DIR)
+    parser.add_argument(
+        "--workspace-template",
+        type=Path,
+        default=DEFAULT_WORKSPACE_TEMPLATE,
+        help="Template directory copied for each local-mode trial workspace.",
+    )
+    parser.add_argument(
+        "--source-root",
+        type=Path,
+        default=EXAMPLE_SOURCE_ROOT,
+        help="Python source root written into each generated trial config.",
+    )
     parser.add_argument("--server-url", default=None)
     parser.add_argument("--start-server", action="store_true", default=False)
     parser.add_argument("--no-start-server", action="store_false", dest="start_server")
@@ -407,14 +426,16 @@ def main(argv: list[str] | None = None) -> int:
                     model=args.model,
                     index=index,
                     workspaces_dir=args.workspaces_dir,
+                    template_dir=args.workspace_template,
+                    source_root=args.source_root,
                 )
                 if args.prompt == DEFAULT_PROMPT:
                     prompt_path = workspace.prompt_path
                 trial_wf_command_prefix = wf_command_prefix_for_config(
                     workspace.config_path
                 )
-                workspace_path = workspace.root.relative_to(ROOT).as_posix()
-                config_path = workspace.config_path.relative_to(ROOT).as_posix()
+                workspace_path = _display_path(workspace.root)
+                config_path = _display_path(workspace.config_path)
                 trial_server_context = (
                     "No external workflow RPC server is staged. Use the "
                     "per-trial workspace config copied to "
@@ -437,7 +458,7 @@ def main(argv: list[str] | None = None) -> int:
                     "classification": result["classification"],
                     "returncode": result["returncode"],
                     "duration_seconds": round(float(result["duration_seconds"]), 3),
-                    "report_path": result.get("report_path"),
+                    "report_path": _optional_string(result.get("report_path")),
                     "report_save_error": result.get("report_save_error"),
                 }
             )
@@ -453,5 +474,9 @@ def main(argv: list[str] | None = None) -> int:
             stop_server(managed_server.process)
 
 
+def _optional_string(value: object) -> str | None:
+    return None if value is None else str(value)
+
+
 if __name__ == "__main__":
     raise SystemExit(main())