Four-layer security model for ultraexecute-local and headless sessions:
Layer 1 — Plugin hooks: pre-bash-executor.mjs (13 BLOCK + 8 WARN rules
with bash evasion normalization) and pre-write-executor.mjs (8 path guard
rules blocking .git/hooks, .claude/settings, shell configs, .env, SSH/AWS).
Layer 2 — Prompt-level security rules: denylist in ultraexecute-local.md
Sub-step D and session-spec-template.md Security Constraints section.
These are the only rules that work in headless child sessions.
Layer 3 — Pre-execution plan validation: new Phase 2.4 scans all Verify
and Checkpoint commands against denylist before execution begins.
Layer 4 — Replace --dangerously-skip-permissions with scoped
--allowedTools "Read,Write,Edit,Bash,Glob,Grep" --permission-mode
bypassPermissions in ultraexecute-local.md, headless-launch-template.md,
and session-decomposer.md. Blocks Agent, MCP, WebSearch in child sessions.
Also adds Hard Rules 14-16: verify command security check, no writing
outside repository root, no writing to security-sensitive paths.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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