Write bytes to an open serial session. Safety preflight is enforced unless explicitly skipped.
Risk signalsHigh parameter count (19 properties)
Part of the Arduino MCP Server server.
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AI agents use serial_write to create or modify resources in Arduino MCP Server. 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 serial_write 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 Arduino MCP Server.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
{
"version": "1",
"default": "deny",
"tools": {
"serial_write": {
"limits": [
{
"counter": "serial_write_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}See the full Arduino MCP Server policy for all 21 tools.
These attack patterns abuse exactly the kind of access serial_write 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.
Write bytes to an open serial session. Safety preflight is enforced unless explicitly skipped.. It is categorised as a Write tool in the Arduino MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Arduino MCP Server MCP server in PolicyLayer and add a rule for serial_write: 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 Arduino MCP Server. Nothing to install.
serial_write 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 serial_write 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 serial_write. 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.
serial_write is provided by the Arduino MCP Server MCP server (akshatnerella/arduino-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 21 Arduino MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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4,600+ MCP servers and 31,000+ tools scanned and risk-classified.