feat: parse structured challenge reports

examples/agent_challenges/browser_click_challenge/README.md

@@ -50,6 +50,27 @@ The baseline challenge does not require Playwright MCP. The score is based on
 whether the agent used the workflow product path and produced the expected
 workflow output.
 
+## Required Agent Report
+
+The prompt asks the agent to end with one fenced YAML block:
+
+```yaml
+challenge_report:
+  used_product_path: true
+  used_helper_script: false
+  workflow_file: "path/to/workflow.json-or-yaml"
+  deployment_id: "browser_click_case_study.default"
+  run_id: "run_..."
+  before_clicked: false
+  after_clicked: true
+  run_failed: false
+  leftover_processes: false
+  notes: "short explanation"
+```
+
+The harness parses this report first. If the report is missing, it falls back to
+best-effort prose classification.
+
 ## Classification
 
 Each trial is classified as one of:

examples/agent_challenges/browser_click_challenge/prompt.md

@@ -35,4 +35,24 @@ You may inspect and use it. A successful final answer must include:
 - evidence that `after.clicked` is `true`,
 - whether any server/browser process remains running.
 
+End your answer with exactly one fenced YAML block using this shape:
+
+```yaml
+challenge_report:
+  used_product_path: true
+  used_helper_script: false
+  workflow_file: "path/to/workflow.json-or-yaml"
+  deployment_id: "browser_click_case_study.default"
+  run_id: "run_..."
+  before_clicked: false
+  after_clicked: true
+  run_failed: false
+  leftover_processes: false
+  notes: "short explanation"
+```
+
+Set `used_product_path` to true only if the workflow was applied and run through
+the `wf` CLI or `wf-rpc-server` path. Set `used_helper_script` to true if you
+created a Python script to drive `WorkflowApi` directly.
+
 If something fails, report the exact command and error instead of hiding it.

examples/agent_challenges/browser_click_challenge/run_opencode_trials.py

@@ -8,6 +8,8 @@ from dataclasses import asdict, dataclass
 from pathlib import Path
 from typing import Any, Literal
 
+import yaml
+
 Classification = Literal[
     "success",
     "workflow_script",
@@ -111,6 +113,10 @@ def _event_text(event: dict[str, Any]) -> str | None:
 
 
 def classify_output(text: str) -> Classification:
+    report = extract_challenge_report(text)
+    if report is not None:
+        return classify_challenge_report(report)
+
     lowered = text.lower()
     product_command_markers = [
         "wf ",
@@ -121,9 +127,7 @@ def classify_output(text: str) -> Classification:
         "run id",
         "run_",
     ]
-    used_product_command = any(
-        marker in lowered for marker in product_command_markers
-    )
+    used_product_command = any(marker in lowered for marker in product_command_markers)
     has_workflow_evidence = any(
         marker in lowered for marker in workflow_evidence_markers
     )
@@ -162,6 +166,59 @@ def classify_output(text: str) -> Classification:
     return "unknown"
 
 
+def extract_challenge_report(text: str) -> dict[str, Any] | None:
+    """Extract the required final YAML challenge report from agent output."""
+    marker = "```yaml"
+    start = text.lower().rfind(marker)
+    if start == -1:
+        return None
+    body_start = text.find("\n", start)
+    if body_start == -1:
+        return None
+    end = text.find("```", body_start + 1)
+    if end == -1:
+        return None
+    raw_yaml = text[body_start + 1 : end]
+    loaded = yaml.safe_load(raw_yaml)
+    if not isinstance(loaded, dict):
+        return None
+    report = loaded.get("challenge_report")
+    return report if isinstance(report, dict) else None
+
+
+def classify_challenge_report(report: dict[str, Any]) -> Classification:
+    used_product_path = report.get("used_product_path") is True
+    used_helper_script = report.get("used_helper_script") is True
+    workflow_file = report.get("workflow_file")
+    deployment_id = report.get("deployment_id")
+    run_id = report.get("run_id")
+    before_clicked = report.get("before_clicked")
+    after_clicked = report.get("after_clicked")
+    failed = report.get("run_failed") is True
+
+    if failed:
+        return "run_failed"
+    if used_helper_script:
+        return "workflow_script"
+    if (
+        used_product_path
+        and isinstance(workflow_file, str)
+        and bool(workflow_file)
+        and isinstance(deployment_id, str)
+        and bool(deployment_id)
+        and isinstance(run_id, str)
+        and bool(run_id)
+        and before_clicked is False
+        and after_clicked is True
+    ):
+        return "success"
+    if not used_product_path and (
+        before_clicked is not None or after_clicked is not None
+    ):
+        return "workflow_not_used"
+    return "unknown"
+
+
 def _contains_bool_marker(text: str, marker: str, value: str) -> bool:
     marker_index = text.find(marker)
     if marker_index == -1: