feat: add opencode browser click challenge harness

- Challenge prompt requiring workflow/deployment/run evidence
- CLI harness (run_opencode_trials.py) for running N agent trials
- Classification: success, workflow_not_used, run_failed, timeout, parse_error, unknown
- 8 unit tests covering build/parse/classify/path logic
- README with usage docs and optional Playwright MCP attachment
- Evidence index and roadmap updated
- Plan archived to historical/

tests/examples/test_opencode_browser_click_challenge.py

@@ -0,0 +1,116 @@
+from __future__ import annotations
+
+import json
+from pathlib import Path
+
+from examples.agent_challenges.browser_click_challenge.run_opencode_trials import (
+    TrialConfig,
+    build_opencode_command,
+    classify_output,
+    parse_opencode_output,
+    trial_output_path,
+)
+
+
+def test_build_opencode_command_without_attach(tmp_path: Path) -> None:
+    prompt = tmp_path / "prompt.md"
+    prompt.write_text("hello", encoding="utf-8")
+    config = TrialConfig(
+        model="opencode/mimo-v2.5-free",
+        variant="high",
+        prompt_path=prompt,
+        attach_url=None,
+        timeout_seconds=120,
+    )
+
+    command = build_opencode_command(config)
+
+    assert command[:2] == ["opencode", "run"]
+    assert "--attach" not in command
+    assert "--format" in command
+    assert "json" in command
+    assert "--model" in command
+    assert "opencode/mimo-v2.5-free" in command
+    assert "hello" in command
+
+
+def test_build_opencode_command_with_attach(tmp_path: Path) -> None:
+    prompt = tmp_path / "prompt.md"
+    prompt.write_text("hello", encoding="utf-8")
+    config = TrialConfig(
+        model="opencode/deepseek-v3.1-free",
+        variant="high",
+        prompt_path=prompt,
+        attach_url="http://127.0.0.1:4096",
+        timeout_seconds=120,
+    )
+
+    command = build_opencode_command(config)
+
+    assert "--attach" in command
+    assert "http://127.0.0.1:4096" in command
+
+
+def test_parse_opencode_output_reads_json_object() -> None:
+    payload = {"text": "wf run start demo.default\nbefore.clicked false\nafter.clicked true"}
+
+    parsed = parse_opencode_output(json.dumps(payload))
+
+    assert parsed["text"] == payload["text"]
+
+
+def test_parse_opencode_output_reads_last_jsonl_object() -> None:
+    payload = "\n".join(
+        [
+            json.dumps({"type": "log", "text": "starting"}),
+            json.dumps({"type": "message", "text": "final"}),
+        ]
+    )
+
+    parsed = parse_opencode_output(payload)
+
+    assert parsed["text"] == "final"
+
+
+def test_classify_output_success() -> None:
+    result = classify_output(
+        """
+        uv run wf-rpc-server --config examples/browser_click_workflow/wf.config.json
+        uv run wf run start browser_click_case_study.default
+        deployment id: browser_click_case_study.default
+        run id: run_123
+        before.clicked is false
+        after.clicked is true
+        """
+    )
+
+    assert result == "success"
+
+
+def test_classify_output_workflow_not_used() -> None:
+    result = classify_output(
+        """
+        I wrote a Playwright script.
+        before clicked false
+        after clicked true
+        """
+    )
+
+    assert result == "workflow_not_used"
+
+
+def test_classify_output_run_failed() -> None:
+    result = classify_output(
+        """
+        wf run start browser_click_case_study.default
+        error: deployment validation failed
+        """
+    )
+
+    assert result == "run_failed"
+
+
+def test_trial_output_path_is_zero_padded(tmp_path: Path) -> None:
+    path = trial_output_path(tmp_path, model="opencode/mimo-v2.5-free", index=3)
+
+    assert path.name == "opencode_mimo-v2.5-free-trial-003.json"