{"record":{"id":"545a38350982ac6a","repo":"bytedance/deer-flow","slug":"missing-yaml-front-matter","errorCode":null,"errorMessage":"missing YAML front matter","messagePattern":"missing YAML front matter","errorType":"exception","errorClass":"ValueError","httpStatus":null,"severity":"error","filePath":"backend/packages/harness/deerflow/agents/memory/backends/deermem/deermem/core/storage.py","lineNumber":293,"sourceCode":"    return (first or \"Memory fact\")[:160]\n\n\ndef _render_fact_markdown(fact: dict[str, Any]) -> bytes:\n    metadata = {key: copy.deepcopy(value) for key, value in fact.items() if key not in {\"content\", \"title\"}}\n    scope = metadata.pop(\"scope\", {})\n    if isinstance(scope, dict):\n        metadata[\"user_id\"] = scope.get(\"userId\")\n        metadata[\"agent_name\"] = scope.get(\"agentName\")\n    front_matter = yaml.safe_dump(metadata, allow_unicode=True, sort_keys=False).strip()\n    text = f\"---\\n{front_matter}\\n---\\n\\n# {_fact_title(fact)}\\n\\n{fact['content'].rstrip()}\\n\"\n    return text.encode(\"utf-8\")\n\n\ndef _parse_fact_markdown(path: Path) -> dict[str, Any]:\n    try:\n        text = path.read_text(encoding=\"utf-8\")\n        if not text.startswith(\"---\\n\"):\n            raise ValueError(\"missing YAML front matter\")\n        front, body = text[4:].split(\"\\n---\\n\", 1)\n        metadata = yaml.safe_load(front) or {}\n        if not isinstance(metadata, dict):\n            raise ValueError(\"front matter is not a mapping\")\n        body = body.lstrip(\"\\n\")\n        lines = body.splitlines()\n        title = \"\"\n        if lines and lines[0].startswith(\"# \"):\n            title = lines.pop(0)[2:].strip()\n            if lines and not lines[0].strip():\n                lines.pop(0)\n        metadata[\"title\"] = title\n        metadata[\"content\"] = \"\\n\".join(lines).rstrip(\"\\n\")\n        metadata[\"scope\"] = {\n            \"userId\": metadata.pop(\"user_id\", None),\n            \"agentName\": metadata.pop(\"agent_name\", None),\n        }\n        return metadata","sourceCodeStart":275,"sourceCodeEnd":311,"githubUrl":"https://github.com/bytedance/deer-flow/blob/1dd6ba1acb03700589994b0366c5d1c7d05e2eff/backend/packages/harness/deerflow/agents/memory/backends/deermem/deermem/core/storage.py#L275-L311","documentation":"Error \"missing YAML front matter\" thrown in bytedance/deer-flow.","triggerScenarios":"Thrown at backend/packages/harness/deerflow/agents/memory/backends/deermem/deermem/core/storage.py:293 when the library encounters an invalid state.","commonSituations":"See trigger scenarios.","solutions":["Add YAML front matter (--- delimited block) to the fact file.","Regenerate the fact via the memory API so it is written in canonical format."],"exampleFix":null,"handlingStrategy":null,"validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"1dd6ba1acb03700589994b0366c5d1c7d05e2eff","analyzedAt":"2026-08-14T21:20:34.804Z","schemaVersion":2},"datasetVersion":"2026-08-15T22:17:37.221Z"}