feat(tasks): add skill-templated task graph execution

app-instance/backend/beaver/tasks/evidence.py

@@ -2,6 +2,8 @@
 
 from __future__ import annotations
 
+import json
+import re
 from dataclasses import dataclass, field
 from typing import Any
 
@@ -126,6 +128,37 @@ class EvidenceBuilder:
         )
 
 
+def evaluate_node_evidence(
+    evidence: RunEvidence,
+    required_evidence: list[str],
+    output_text: str,
+) -> list[str]:
+    """Evaluate v1 coarse-grained node evidence requirements."""
+
+    gaps: list[str] = []
+    successful_tools = [
+        item
+        for item in evidence.tool_results
+        if item.event_payload.get("success") is True
+    ]
+    for raw_requirement in required_evidence:
+        requirement = str(raw_requirement).strip()
+        if not requirement:
+            continue
+        if requirement == "tool_result":
+            if not successful_tools:
+                _append_unique(gaps, "missing required evidence: tool_result")
+        elif requirement == "url":
+            if not any(_tool_evidence_contains_url(item) for item in successful_tools):
+                _append_unique(gaps, "missing required evidence: url")
+        elif requirement == "output":
+            if not output_text.strip():
+                _append_unique(gaps, "missing required evidence: output")
+        else:
+            _append_unique(gaps, f"unsupported evidence requirement: {requirement}")
+    return gaps
+
+
 def render_task_evidence(packet: TaskEvidencePacket) -> str:
     sections = [
         f"Task evidence packet: task_id={packet.task_id} attempt={packet.attempt_index}",
@@ -181,3 +214,20 @@ def _render_tool_evidence(item: ToolEvidence) -> str:
 
 def _optional_str(value: Any) -> str | None:
     return str(value) if value is not None else None
+
+
+_URL_RE = re.compile(r"https?://[^\s<>'\"]+", re.IGNORECASE)
+
+
+def _tool_evidence_contains_url(item: ToolEvidence) -> bool:
+    values = [
+        item.url or "",
+        item.content,
+        json.dumps(item.event_payload, ensure_ascii=False, default=str),
+    ]
+    return any(_URL_RE.search(value) is not None for value in values)
+
+
+def _append_unique(values: list[str], value: str) -> None:
+    if value not in values:
+        values.append(value)