Policy

Before any tool call runs, Nu’s kernel checks it against your policy. The first rule that matches decides, and a call that no rule matches waits for your approval. Model calls are always allowed. Your rules live in ~/.nu/policy.yaml. Nu starts with these:

Rule	Allows
`reads`	Searching memory and packages, listing schedules, reading the policy, and looking at the browser page
`nu-state`	Nu’s own memory, skills, schedules, background tasks, delegation, and asking you for secrets
`workspace`	Shell commands and file edits in the sandbox
`message-user`	Messaging you outside a reply, such as when a schedule finishes

Anything else asks first. That includes MCP and package tools, installing or writing packages, browser tasks, messages to anyone but you, and changes to the policy or specialists.

Changing the rules

The quickest way is from an approval card. Always allow adds a rule for that tool, and Write a rule lets you describe the rule you want. See Approvals. You can also ask from chat with /policy, for example /policy ask before any git push. Nu drafts the change and shows it to you before it takes effect. /policy on its own lists the current rules, and nu policy --yaml prints them as YAML. Rules edited in the dashboard take effect within a few seconds. If an edit fails Nu’s checks, Nu undoes it and tells you why. A rule can match the tool name and its arguments:

rules:
  - id: git-status
    when:
      target: shell
      arguments:
        command:
          regex: "^git (status|diff|log)( |$)"
    then:
      decision: allow

  - id: no-linear-deletes
    when:
      target: mcp__linear__delete_*
    then:
      decision: deny

See Policy for the full rule format, including history conditions and rate limits.

Specialists

Each specialist has its own rules, written when it is created. Tools without a matching rule ask first, as they do for Nu.

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Changing the rules

Specialists

​Changing the rules

​Specialists

Changing the rules

Specialists