generate-policy

name	generate-policy
description	Generate a Sigil sandbox policy YAML from scan results for secure agent execution
allowed-tools	Bash(./bin/sigil *), Read, Write, Glob

Generate Sandbox Policy

Generate a Sigil security policy YAML file based on scan results. The policy controls filesystem, network, process, and credential access for sandboxed agent execution.

Process

1. Scan the target — Run ./bin/sigil scan <path> to get findings
2. Analyze findings — Map each finding to a policy restriction:
   • Phase 1 (Install Hooks) → Filesystem restrictions (read-only paths)
   • Phase 3 (Network) → Network allowlist (only permit known-good endpoints)
   • Phase 4 (Credentials) → Credential policy (restrict env var access)
   • Phase 5 (Obfuscation) → Process restrictions (sandboxed user)
3. Generate policy YAML with the following structure:

version: "1.0"
name: "<project-name>-policy"
description: "Auto-generated from Sigil scan on <date>"

filesystem:
  read_only:
    - /usr
    - /lib
    - /etc
  read_write:
    - /tmp
  include_workdir: true

network:
  default_action: deny
  rules:
    - name: "<endpoint-name>"
      host: "<hostname>"
      port: 443
      access: read-only
      enforcement: enforce

process:
  run_as_user: sandbox
  run_as_group: sandbox
  deny_syscall_categories:
    - privilege_escalation

credentials:
  allowed_env:
    - TERM
    - PATH
    - HOME
  denied_env: []
  providers: []

4. Write the policy to sigil-policy.yaml in the project root
5. Explain the policy — For each section, explain what it restricts and why

Policy Severity Mapping

Scan Verdict	Network Policy	Credential Policy	Process Policy
CLEAN	permissive	allow common	standard
LOW RISK	standard endpoints	allow declared	standard
MEDIUM RISK	strict allowlist	minimal	sandboxed user
HIGH RISK	deny all	deny all	full restrictions
CRITICAL	deny all + log	deny all	full restrictions

Rules

• Always explain WHY each restriction exists (reference the specific finding)
• For CLEAN scans, still generate a minimal security policy
• Include comments in the YAML explaining each rule
• Suggest the user review and customize before applying