Automatically format time series data (frequency, duplicates, missing values)
AI agents use format_time_series to create or update resources in Sktime — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Sktime environment.
This tool modifies/transforms data by formatting it — handling frequency, removing duplicates, and filling missing values. These are reversible data transformations (Write), not destructive operations. The blast radius is medium since it modifies the structure of time series data that may feed into downstream ML workflows.
From the tool's definition Automatically format time series data (frequency, duplicates, missing values)
Documented attack patterns abuse exactly the kind of access format_time_series gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Sktime, and nothing reaches the server without passing your rules. This is the rule we recommend for format_time_series:
{
"version": "1",
"default": "deny",
"tools": {
"format_time_series": {
"limits": [
{
"counter": "format_time_series_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}format_time_series 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.
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Automatically format time series data (frequency, duplicates, missing values). It is categorised as a Write tool in the Sktime MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Sktime MCP server in PolicyLayer and add a rule for format_time_series: 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 Sktime. Nothing to install.
format_time_series 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 format_time_series 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 format_time_series. 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.
format_time_series is provided by the Sktime MCP server (sktime/sktime-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Sktime, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
24 Sktime tools catalogued and risk-classified — across an index of 43,000+ MCP servers.