AI coding agents take shortcuts when you stop watching. They call hacks "pragmatic," blame "pre-existing issues," and delete failing tests to get to green. AgentCheck is a stdin/stdout proxy that sits in front of the agent and pushes back before those changes land.
┌───────────────────────────────────────────────────────────────┐
│ Without AgentCheck │
│ Agent: "I'll use a pragmatic fix here..." │
│ Agent: [adds a workaround] │
│ Agent: "Tests were flaky, so I removed one." │
│ Agent: "Done." │
│ You: [return later and sort out the damage] │
└───────────────────────────────────────────────────────────────┘
┌───────────────────────────────────────────────────────────────┐
│ With AgentCheck │
│ Agent: "I'll use a pragmatic fix here..." │
│ ↳ [agentcheck]: "Do the correct fix. If it is bigger, ask." │
│ Agent: "You're right. Let me fix the root cause." │
│ Agent: [keeps the test and fixes the failure] │
│ You: [review a normal diff] │
└───────────────────────────────────────────────────────────────┘
npm install -g github:paprika-org/agentcheckagentcheck -- claudePut agentcheck -- in front of the agent command you already use.
If this saved you from a runaway session, star it — helps others find it.
GitHub: https://github.com/paprika-org/agentcheck
agentcheck -- cursor-agent --headless agentcheck -- aider --model gpt-5.4
agentcheck --dry-run -v -- claude
agentcheck --log ~/.agentcheck.log -- claude
**Shadow mode** (`--shadow`) runs your agent normally but silently logs every rule that *would* have fired to `.agentcheck-shadow.log`. Nothing is injected. Use this to build confidence in your ruleset before enabling live corrections.
## Rule Packs
Pre-built rule packs in the `rules/` directory:
| Pack | What it catches |
|------|----------------|
| `rules/protect-git.yaml` | Destructive git ops: force push, hard reset, branch delete, checkout dot |
| `rules/no-secrets.yaml` | Hardcoded credentials, API keys, tokens, private keys, connection strings |
| `rules/stay-in-scope.yaml` | Out-of-scope file edits: lockfiles, .env, CI/CD, migrations, sudo, rm -rf |
```bash
# Use a rule pack
agentcheck --config rules/protect-git.yaml -- claude
# Shadow mode with a rule pack (observe before committing)
agentcheck --shadow --config rules/no-secrets.yaml -- claude
AgentCheck ships with rules for the most common agent failure modes:
| Rule | Triggers on | Injects |
|---|---|---|
pragmatic-fix |
"pragmatic fix/solution/approach" | Reminder to do the correct fix |
pre-existing |
"pre-existing issue/bug/problem" | Don't blame pre-existing issues |
deleted-tests |
Deleting tests | STOP. Fix the code, not the test. |
skip-tests |
.skip(), xit(), xdescribe() |
STOP. Fix the issue, don't skip. |
already-working |
"already works/passes" | Show me the test that proves it. |
error-swallow |
Empty catch blocks | Handle or re-throw errors. |
See all rules: agentcheck --rules
Create .agentcheck.yml in your project root:
include_defaults: true # keep built-in rules (default)
rules:
# Your team's rules
- pattern: "TODO: fix later"
inject: "Don't leave TODOs. Fix it now or file an issue with a ticket number."
cooldown: 30
- pattern: "I'll leave this for now"
inject: "Finish this before moving on. What specifically would you leave and why?"
cooldown: 60
- pattern: "assuming .* works"
inject: "Don't assume — verify. Run the thing and check the output."
cooldown: 60AgentCheck is a transparent proxy:
- Spawns your agent as a subprocess
- Pipes your terminal's stdin → agent stdin (your input goes through unchanged)
- Pipes agent stdout → your terminal (you see everything)
- Scans each line of agent output against your ruleset
- When a rule matches: injects the correction text into agent stdin
- Per-rule cooldowns prevent injection spam
The agent receives your correction as if you typed it — no framework changes, no API keys, no agent-specific integration.
Tools like TruPal watch agent behavior and show you alerts. That requires you to be watching.
AgentCheck acts — it injects the correction automatically, in real-time, before the agent continues down the wrong path. You set the rules once and let the agent run unattended.
v0.1 — core proxy and injection works. Collecting feedback on which rules matter most.
→ Try it and tell us what rules you'd add: [email protected]
→ Want the hosted version (web dashboard, team rules, Slack alerts, injection history): join the waitlist
Use agentcheck in GitHub Actions to audit AI agent output without injecting:
- name: Install agentcheck
run: npm install -g agentcheck
- name: Run agent with guardrails (shadow mode)
run: |
agentcheck --shadow --shadow-log /tmp/agentcheck.log -- your-agent-command
- name: Upload shadow log
uses: actions/upload-artifact@v4
with:
name: agentcheck-shadow-log
path: /tmp/agentcheck.logShadow mode observes what rules would have fired without modifying agent output. Upload the log as an artifact to audit AI sessions in CI.
See .github/workflows/agentcheck-demo.yml for a full working example.
MIT