Create a frontend deployment and get an upload URL. Upload your built frontend as a zip file to the returned URL, then use manage_frontend (action: "start_deployment") to trigger the deploy. Steps: 1. Call this tool to get an upload URL 2. Upload your zip file to the URL (e.g. curl -X PUT "{uploa...
Risk signalsBulk/mass operation — affects multiple targets
Part of the Mcp server.
Free to start. No card required.
AI agents use create_frontend_deployment to create or modify resources in Mcp. Write operations carry medium risk because an autonomous agent could trigger bulk unintended modifications. Rate limits prevent a single agent session from making hundreds of changes in rapid succession. Argument validation ensures the agent passes expected values.
Without a policy, an AI agent could call create_frontend_deployment repeatedly, creating or modifying resources faster than any human could review. PolicyLayer's rate limiting ensures write operations happen at a controlled pace, and argument validation catches malformed or unexpected inputs before they reach Mcp.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
{
"version": "1",
"default": "deny",
"tools": {
"create_frontend_deployment": {
"limits": [
{
"counter": "create_frontend_deployment_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}See the full Mcp policy for all 47 tools.
These attack patterns abuse exactly the kind of access create_frontend_deployment gives an agent. Each links to the full case and the policy that stops it:
Other write tools across the catalogue. The same approach applies to each: rate-limit and validate the arguments.
Create a frontend deployment and get an upload URL. Upload your built frontend as a zip file to the returned URL, then use manage_frontend (action: "start_deployment") to trigger the deploy. Steps: 1. Call this tool to get an upload URL 2. Upload your zip file to the URL (e.g. curl -X PUT "{uploadUrl}" -H "Content-Type: application/zip" --data-binary @frontend.zip) 3. Call manage_frontend (action: "start_deployment") with the returned deployment_id Example: Input: { app_id: "app_abc123", framework: "react-vite" } Output: { deployment_id: "uuid-1234", uploadUrl: "https://...", expiresIn: 900, maxSizeBytes: 104857600 } Prerequisites: - App must exist (use init_app to create) Free plan: 1 deployment per app. Deploying again automatically replaces the previous deployment (no need to delete first). Starter+: unlimited deployments. Framework options: - react-vite: React app built with Vite (zip the dist/ folder) - nextjs-static: Next.js static export (zip the out/ folder) - static: Plain HTML/CSS/JS - other: Any framework that produces static output SPA routing: For SPA frameworks (react-vite, nextjs-static, other), a _redirects file is auto-injected so all routes serve index.html. If your zip already includes a _redirects file, it is preserved. IMPORTANT — Zip file paths must use forward slashes (/), not backslashes (\). On Windows, zips created with built-in tools use backslashes, which causes all files to be served as text/html (breaking JS/CSS with MIME errors). On Windows use Git Bash or WSL to run: cd dist && zip -r ../frontend.zip . Common errors: - RESOURCE_NOT_FOUND: App doesn't exist Idempotency: Not idempotent — creates a new deployment each time (replaces existing on free plan). Your frontend will be deployed to https://<app-name>.butterbase.dev. Next steps: Upload your zip to the returned URL, then call manage_frontend (action: "start_deployment").. It is categorised as a Write tool in the Mcp MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the MCP server in PolicyLayer and add a rule for create_frontend_deployment: 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 Mcp. Nothing to install.
create_frontend_deployment 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 create_frontend_deployment 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 create_frontend_deployment. 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.
create_frontend_deployment is provided by the MCP server (@butterbase/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 47 Mcp tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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