tack-guard
FREE · MITThe open-source SDK. Drops into any agent, scores every call locally.
- Scoring engine (6 signals, 0 → 1)
- Pattern detection (3 attack types)
- Stateless signatures
- Multi-agent isolation
- Zero dependencies, <1ms
- MIT open source
COMING SOON
OPEN SOURCE · RUNS LOCALLY · <1MS INLINE
Tack learns each agent's behavioral baseline and scores how far it has drifted, catching credential-creep and anomalies that stateless policies miss. Contain threats inline: warn, block, or quarantine.
$ npm install tack-guard
import { createGuard } from 'tack-guard'
const guard = createGuard()
// score every tool call · 0 → 1 · locally
const { score, verdict } = guard.evaluate(toolCall)
if (verdict === 'quarantine') block() THE BLIND SPOT
Every tool out there does binary allow or block. Each call is judged alone, so the attack that unfolds across calls walks straight through.
Each action looks fine. Only the trajectory reveals the threat.
The slow attack. Read-only baseline, then writes, then sensitive data. Each step looks harmless.
The loud attack. Bulk export, mass delete, exfiltration. Obvious but still needs catching.
The weird attack. After-hours access, volume spikes, admin attempts. Doesn't match any known pattern.
HOW IT WORKS
One inline loop wraps every action your agent takes. Tack learns, scores, and contains, before the call ever runs.
Tack observes the first N calls and learns what "normal" looks like for each agent.
Each subsequent tool call is scored 0 → 1 against the baseline. Six weighted signals, combined into a risk score.
Warn, block, or quarantine. In under a millisecond. Before the action executes.
TRY IT NOW
Drop it into your tool-call pipeline. It scores locally, returns instantly, and never phones home.
LangChain ·OpenAI ·Anthropic ·MCP ·any agent framework
import { createGuard } from 'tack-guard'
const guard = createGuard({
sensitiveTargets: ['user_db', 'credentials', 'billing'],
mode: 'enforce'
})
// wrap your agent's tool calls
const result = guard.evaluate({
agentId: 'sales-bot',
action: 'read',
target: 'user_db',
hour: 14
})
if (result.blocked) {
console.warn(`Blocked: ${result.pattern} (score: ${result.score})`)
} FREE VS CLOUD
The guard is free forever. Cloud adds the memory that survives restarts and correlates behavior across sessions.
The open-source SDK. Drops into any agent, scores every call locally.
Hosted memory and correlation. The fleet view across every session.
Everything in tack-guard, plus:
WHY MEMORY WINS
Rules catch what you already named. A learned baseline catches the escalation no one wrote a rule for.
| Approach | Detects loud attacks | Detects slow escalation | Learns from history | Inline (<1ms) |
|---|---|---|---|---|
| Policy engine | yes | no | no | yes |
| Proxy / WAF | yes | no | no | partial |
| Log monitoring | yes | post-mortem | no | no |
| tack-guard | yes | yes | yes | yes |
✓ yes ✗ no ~ △ partial
WHO'S BUILDING THIS
Technical founder · San Francisco
French founder building in San Francisco. Built Tack's scoring engine live at the Agent Native Company Hackathon (Beta x Nebius) in Sunnyvale, then open-sourced it as tack-guard. Breaking AI agents to learn how to defend them.
Origin: Agent Native Company Hackathon (Beta x Nebius), Sunnyvale, June 2026
SIGNAL, NOT NOISE
tack-guard is open-sourcing soon under the MIT license: the scoring engine, the detection rules, and this site. Follow along for the drop, then read the code and judge the behavior for yourself. No telemetry, no signup.
SHIP WITH A BASELINE
Open source, dropping soon. Follow along for the launch.
npm install tack-guard soon