# Best Pre-Action Check Tools for AI Coding Agents (2026 Comparison)

Your AI coding agent force-pushed to main again. Which tool actually prevents that? We compared the five most common approaches to AI agent safety.

## Comparison Table

Feature | ThumbGate | Manual Code Review | Post-hoc Git Revert | Cursor Rules / .cursorrules | ESLint / Linters
--- | --- | --- | --- | --- | ---
Blocks bad actions before execution | Yes -- PreToolUse hooks | Partially -- after PR only | No -- damage already done | Partially -- suggestions only | Partially -- static checks only
Learns from past mistakes | Yes -- auto-generates rules from feedback | No -- relies on reviewer memory | No | No -- rules are hand-written | No -- rules are hand-written
Works with Claude / Codex / Gemini / Forge | Yes -- all MCP-compatible agents | Yes -- agent-agnostic | Yes -- agent-agnostic | Cursor only | Partial -- code-level only
Zero config setup | Yes -- `npx thumbgate init` | No -- requires process + people | No -- manual intervention each time | Partial -- requires writing rules | Partial -- requires config + plugins
Captures feedback for improvement | Yes -- thumbs up/down with context | Partial -- PR comments only | No | No | No
Generates prevention rules automatically | Yes -- from repeated failure patterns | No | No | No | No
Real-time pre-action checks | Yes -- fires before every tool call | No -- asynchronous review | No -- reactive only | No -- prompt-time only | No -- build-time only
Cost | Free tier + Pro $19/mo | Engineer time per review | Time lost + recovery cost | Free | Free (open source)
Academic validation | Memento-Skills architecture (arXiv 2603.18743) | — | — | — | —

## Why ThumbGate Wins

- Enforcement, not suggestions. Prompt rules in CLAUDE.md or .cursorrules are instructions the agent can ignore. ThumbGate intercepts tool calls at the PreToolUse hook level and physically blocks dangerous actions before they execute.
- Learns and adapts automatically. Every thumbs-down becomes a data point. After repeated failures with the same pattern, ThumbGate auto-generates a prevention rule. Checks adapt their sensitivity over time using Thompson Sampling -- aggressive checks that over-block get tuned down, effective checks get reinforced.
- Works across all major AI coding agents. One install command covers Claude Code, Cursor, Codex, Gemini CLI, Amp, Cline, and OpenCode. No per-agent configuration needed.
- Prevention is cheaper than recovery. Manual code review catches mistakes after the PR. Git revert catches them after the push. ThumbGate catches them before the tool call executes -- saving the time, context switches, and cleanup cost of undoing damage.

### Evaluating bigger orchestration platforms?

Journey orchestration and AI workflow routing are different from execution enforcement. If you are comparing ThumbGate to a broader AI orchestration stack, start here.

Read orchestration vs enforcement

### Comparing custom AI agent agencies?

AI automation agencies validate the same buyer pain: production agents need safe action execution, policy checks, observability, and approval boundaries. ThumbGate owns the productized enforcement layer under those workflows.

Read ThumbGate vs Agentix Labs

### Already using a supply-chain scanner?

HEIDI (Meterian) catches AI assistants suggesting vulnerable npm/pip/maven packages — the supply-chain half of AI coding safety. ThumbGate is the behavior half: it blocks the agent's tool call before it fires a known-bad pattern. Different threat surfaces, both local-first, both free at base. Run both.

Read ThumbGate vs HEIDI

### Evaluating Rein for AI agent governance?

Rein is a Python decorator that wraps tool functions with policy checks, audit trails, and circuit breakers — targeted at production apps in trading, healthcare, and legal. ThumbGate is the coding-agent specialist with a learning feedback loop and MIT licensing. Same category (infrastructure firewalls), different layer and stack.

Read ThumbGate vs Rein

## How It Works

1

### Install

Run `npx thumbgate init`. ThumbGate auto-detects your AI coding agent and configures PreToolUse hooks. No manual setup needed.

2

### Check

Every tool call your agent makes passes through a pre-action check. Known-bad patterns are blocked before execution. Good actions pass through instantly.

3

### Learn

When your agent makes a mistake, give it a thumbs-down. In the current Claude auto-capture path, vague negative signals can reuse up to 8 prior recorded entries plus the failed tool call, then stay linked to a 60-second follow-up session before repeated failures harden into prevention rules.

## Get Started

Install ThumbGate in one command:

    npx thumbgate init

Then start giving feedback. ThumbGate handles the rest.

View on npm View on GitHub

## Frequently Asked Questions

### What is a pre-action check?

A pre-action check is an enforcement layer that intercepts AI agent tool calls before they execute. Unlike prompt rules that agents can ignore, pre-action checks physically block dangerous actions such as force-pushing to main, deleting production files, or committing code with failing tests.

### Does ThumbGate work with Claude Code?

Yes. ThumbGate works with Claude Code, Cursor, Codex, Gemini CLI, Amp, Cline, OpenCode, and any MCP-compatible agent. Run `npx thumbgate init --agent claude-code` to auto-configure PreToolUse hooks.

### Is ThumbGate free?

ThumbGate has a free tier that includes local enforcement with unlimited feedback captures, up to 5 active auto-promoted prevention rules, and pre-action check blocking. Pro ($19/mo or $149/yr) adds a personal local dashboard, recall, lesson search, unlimited rules, and DPO export. Team rollout ($49/seat/mo) adds a shared lesson database and org dashboard.

### How is ThumbGate different from .cursorrules or CLAUDE.md rules?

Cursor rules and CLAUDE.md are prompt-level instructions that the AI agent can read, forget, or override. ThumbGate enforces rules at the tool-call level via PreToolUse hooks. When a tool call matches a known failure pattern, it is physically blocked before execution. Additionally, ThumbGate auto-generates prevention rules from feedback -- no manual rule writing.

### Can ThumbGate learn from mistakes automatically?

Yes. When your AI agent makes a mistake, give a thumbs-down with context. In the current Claude auto-capture path, vague negative signals can reuse up to 8 prior recorded entries plus the failed tool call, then stay linked to a 60-second follow-up session. After repeated failures with the same pattern, ThumbGate auto-generates a prevention rule and wires it as a pre-action check. Checks adapt over time using Thompson Sampling, a Bayesian multi-armed bandit algorithm.