Start the official MyWallpaper addon dev runner in a project directory and return its localhost endpoints.
Risk signalsAccepts file system path (path)
Part of the Addon server.
Free to start. No card required.
AI agents invoke start_dev_server to trigger processes or run actions in Addon. Execute operations can have side effects beyond the immediate call -- triggering builds, sending notifications, or starting workflows. Rate limits and argument validation are essential to prevent runaway execution.
start_dev_server can trigger processes with real-world consequences. An uncontrolled agent might start dozens of builds, send mass notifications, or kick off expensive compute jobs. PolicyLayer enforces rate limits and validates arguments to keep execution within safe bounds.
Execute tools trigger processes. Rate-limit and validate arguments to prevent unintended side effects.
{
"version": "1",
"default": "deny",
"tools": {
"start_dev_server": {
"limits": [
{
"counter": "start_dev_server_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}See the full Addon policy for all 14 tools.
These attack patterns abuse exactly the kind of access start_dev_server gives an agent. Each links to the full case and the policy that stops it:
Other execute tools across the catalogue. The same approach applies to each: rate-limit and validate the arguments.
Start the official MyWallpaper addon dev runner in a project directory and return its localhost endpoints.. It is categorised as a Execute tool in the Addon MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Addon MCP server in PolicyLayer and add a rule for start_dev_server: 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 Addon. Nothing to install.
start_dev_server is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the start_dev_server 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 start_dev_server. 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.
start_dev_server is provided by the Addon MCP server (@mywallpaper/addon-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 14 Addon tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
4,600+ MCP servers and 31,000+ tools scanned and risk-classified.