gateguard
PreToolUse fact-forcing gate that denies the first Edit/Write/Bash (including MultiEdit) attempt until the agent presents concrete facts (importers, data schemas, verbatim user instruction), then allows retry; A/B-tested at +2.25 quality points.
- Kind
- Skill
- Works with
- Claude Code, Codex
- Languages
- Shell
- Source
- affaan-m/ECC @ d3b8a3e90890
- Path
- skills/gateguard/SKILL.md
- License
- MIT
- Jobs
- Guardrails
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# GateGuard — Fact-Forcing Pre-Action Gate
A PreToolUse hook that forces Claude to investigate before editing. Instead of self-evaluation ("are you sure?"), it demands concrete facts. The act of investigation creates awareness that self-evaluation never did.
## When to Activate
- Working on any codebase where file edits affect multiple modules
- Projects with data files that have specific schemas or date formats
- Teams where AI-generated code must match existing patterns
- Any workflow where Claude tends to guess instead of investigating
## Core Concept
LLM self-evaluation doesn't work. Ask "did you violate any policies?" and the answer is always "no." This is verified experimentally.
But asking "list every file that imports this module" forces the LLM to run Grep and Read. The investigation itself creates context that changes the output.
**Three-stage gate:**
```
1. DENY — block the first Edit/Write/Bash attempt
2. FORCE — tell the model exactly which facts to gather
3. ALLOW — permit retry after facts are presented
```
No competitor does all three. Most stop at deny.
## Evidence
Two independent A/B tests, identical agents, same task:
…