upload_meta_asset
Upload creative(s) — a finished Hermoso ad OR arbitrary user files (e.g. a folder of media from the user’s desktop) — into a connected ad account’s ASSET LIBRARY so the user or a later ad-build step can use them in their OWN campaigns. Pass
This record as markdown: /tools/hermoso/upload-meta-asset.md
What upload_meta_asset does on Hermoso
AI agents use upload_meta_asset to create or update resources in Hermoso, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Hermoso environment.
Why upload_meta_asset is rated Medium
This tool creates or stores new assets (creatives, media files) in a user's advertising account library. While reversible (assets can typically be deleted), it modifies the state of the ad account by introducing new resources that can be used in live campaigns.
From the tool's definition Tool description states 'Upload creative(s)' and 'into a connected ad account's ASSET LIBRARY so the user or a later ad-build step can use them in their OWN campaigns.' The verb 'upload' combined with storage into an ad account asset library indicates data…
Attacks that exploit this kind of access
The rule that runs upload_meta_asset safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Hermoso, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For upload_meta_asset, this is the rule to start with:
upload_meta_asset stays usable, but capped: an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect Hermoso, apply this rule, and every upload_meta_asset call is checked against it from then on.
Questions about upload_meta_asset
Upload creative(s) — a finished Hermoso ad OR arbitrary user files (e.g. a folder of media from the user’s desktop) — into a connected ad account’s ASSET LIBRARY so the user or a later ad-build step can use them in their OWN campaigns. Pass. It is categorised as a Write tool in the Hermoso MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Hermoso MCP server in PolicyLayer and add a rule for upload_meta_asset: 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 Hermoso. Nothing to install.
upload_meta_asset 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_meta_asset 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_meta_asset. 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_meta_asset is provided by the Hermoso MCP server (https://app.hermoso.ai/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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