refresh_asset_previews
Capture fresh preview PNG assets from one or more live TOP nodes and write them to disk. Use it to regenerate stale thumbnails for library/package assets after a network changes; requires a running TouchDesigner bridge and writes image files (destructive).
This record as markdown: /tools/io-github-pantani-tdmcp/refresh-asset-previews.md
What refresh_asset_previews does on tdmcp — TouchDesigner MCP server
AI agents call refresh_asset_previews to permanently remove resources in tdmcp — TouchDesigner MCP server, typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.
Why refresh_asset_previews is rated Critical
The tool captures previews from live nodes and writes/overwrites PNG files on disk. The description itself flags the operation as destructive, meaning it irreversibly overwrites existing image files. While the blast radius is limited to thumbnail/preview assets rather than core project data, the overwrite action is irreversible, placing it in the Destructive category.
From the tool's definition 'write them to disk' and explicitly labeled '(destructive)' in the description; 'regenerate stale thumbnails' by overwriting existing image files
Attacks that exploit this kind of access
The rule that runs refresh_asset_previews safely
PolicyLayer is an MCP gateway: it sits between your AI agents and tdmcp — TouchDesigner MCP server, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For refresh_asset_previews, this is the rule to start with:
refresh_asset_previews is removed from the agent's tool list entirely, so the agent never calls it. The rest of the server keeps working.
The button opens the PolicyLayer dashboard: create your workspace, connect tdmcp — TouchDesigner MCP server, apply this rule, and every refresh_asset_previews call is checked against it from then on.
Questions about refresh_asset_previews
Capture fresh preview PNG assets from one or more live TOP nodes and write them to disk. Use it to regenerate stale thumbnails for library/package assets after a network changes; requires a running TouchDesigner bridge and writes image files (destructive). It is categorised as a Destructive tool in the tdmcp — TouchDesigner MCP server MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.
Register the tdmcp — TouchDesigner MCP server MCP server in PolicyLayer and add a rule for refresh_asset_previews: 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 tdmcp — TouchDesigner MCP server. Nothing to install.
refresh_asset_previews is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.
Yes. Add a rate_limit block to the refresh_asset_previews 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 refresh_asset_previews. 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.
refresh_asset_previews is provided by the tdmcp — TouchDesigner MCP server MCP server (@dpantani/tdmcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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