上传图片或视频到 OSS，返回 ossKey、signedUrl（默认可为公网直链，字段名不变）、时长与「时间轴/原声」提示。视频在后端会转码为 H.264 MP4（便于录屏解码），写入 HTML 时 src 用返回的 URL；不写入 FFmpeg overlay。视频建议 5–15 秒；时长硬上限 10 分钟，单文件上限见 get_material_guidelines。
AI agents use upload_material to create or update resources in Flash Cast — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Flash Cast environment.
This is a Write operation because it creates new resources (uploads media files to OSS) and modifies data (transcodes videos, generates signed URLs). While upload can be reversed by deletion, the tool itself performs reversible creation/modification, not deletion.
From the tool's definition The tool description explicitly states it uploads images or videos to OSS (Object Storage Service), returning ossKey and signedUrl. The verbs 'upload' and 'writes' indicate data creation/modification.
Attacks that exploit this kind of access
上传图片或视频到 OSS，返回 ossKey、signedUrl（默认可为公网直链，字段名不变）、时长与「时间轴/原声」提示。视频在后端会转码为 H.264 MP4（便于录屏解码），写入 HTML 时 src 用返回的 URL；不写入 FFmpeg overlay。视频建议 5–15 秒；时长硬上限 10 分钟，单文件上限见 get_material_guidelines。. It is categorised as a Write tool in the Flash Cast MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Flash Cast MCP server in PolicyLayer and add a rule for upload_material: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Flash Cast. Nothing to install.
upload_material is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the upload_material rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for upload_material. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
upload_material is provided by the Flash Cast MCP server (trtian/flash-cast-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Every MCP server has a record like this.
Type a name, get the same breakdown: verified identity, auth posture, risk grade, capabilities, recommended policy.
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