schedule_task · Yaver MCP: Risk & Policy

WHAT IT DOES

What schedule_task does on Yaver

AI agents use schedule_task to create or update resources in Yaver — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Yaver environment.

PARAMETERS

Parameter	Type	Required	Description
`cron`	string	—	Cron expression (minute hour day month weekday), e.g. '0 9 * * 1-5' for weekdays at 9am
`title`	string	Yes	Task prompt
`run_at`	string	—	ISO8601 datetime for one-shot execution (e.g. '2026-03-22T15:00:00Z')
`runner`	string	—	Runner ID (claude, codex, aider, etc.)
`max_runs`	integer	—	Maximum number of runs (0 = unlimited)
`repeat_interval`	integer	—	Repeat every N minutes

Parameters from the server's own tool schema.

WHY IT NEEDS A POLICY

Why schedule_task needs a policy

An AI agent can call schedule_task faster than any human can review — one bad instruction and it creates or modifies resources in Yaver by the hundred, each call as confident as the last.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

schedule_task Rate-limited

schedule_task 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.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "schedule_task": {
      "limits": [
        {
          "counter": "schedule_task_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Yaver, so you can run agents against it safely.

FAQ

Questions about schedule_task

What does the schedule_task tool do? +

Schedule a task to run at a specific time or on a recurring basis. Supports one-shot (runAt), interval-based (repeatInterval in minutes), and cron expressions. It is categorised as a Write tool in the Yaver MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

What parameters does schedule_task accept? +

schedule_task accepts 6 parameters: cron, title, run_at, runner, max_runs, repeat_interval. Required: title. The full parameter table on this page comes from the server's own tool schema.

How do I enforce a policy on schedule_task? +

Register the Yaver MCP server in PolicyLayer and add a rule for schedule_task: 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 Yaver. Nothing to install.

What risk level is schedule_task? +

schedule_task is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit schedule_task? +

Yes. Add a rate_limit block to the schedule_task 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.

How do I block schedule_task completely? +

Set action: deny in the PolicyLayer policy for schedule_task. 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.

What MCP server provides schedule_task? +

schedule_task is provided by the Yaver MCP server (yaver-cli). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.