Built for production AI agents that need to fetch web content without eating prompt injection or leaking PII. Runs a Playwright-based pipeline that detects 19 categories of indirect prompt injection before sanitization, redacts emails and credit cards, and generates cryptographic proofs that the security pass actually ran. Handles PDF, JSON, and SVG in addition to HTML. The threat detection is granular: you get severity scores, confidence levels, and character offsets for each flagged attack. Designed around EU AI Act compliance requirements, with audit logs and Merkle-chained session ledgers. If your agent reads untrusted web pages and you need both safety and regulatory coverage, this is the tooling for it.
How Visus-MCP helps your MCP-compatible AI agents become EU AI compliant ready
npx visus-mcp@0.28.0
"What the web shows you, Lateos reads safely."
The EU AI Act (Regulation (EU) 2024/1689) is the world's first comprehensive AI law, effective from August 2024. It regulates AI systems based on risk levels, with stringent requirements for general-purpose AI (GPAI) like MCP-compatible agents that process web content.
Non-compliance fines up to €35M or 7% of global turnover.
Visus-MCP provides out-of-the-box EU AI Act alignment through:
visus_verify.Integrate Visus-MCP to future-proof your AI agent against evolving regulations like the EU AI Act. See SECURITY.md for framework mappings.
URL → Playwright Render → Content-Type Detection
→ Specialized Handlers (PDF/JSON/SVG) OR HTML Pipeline
→ IPI Threat Detection (19 categories) → Injection Sanitizer (45 patterns)
→ Worm Detection (15 Morris II patterns) → PII Redactor → Cryptographic Proof
→ Token Ceiling (24k cap) → Clean Content + Proof + Threat Summary → MCP-compatible AI agent
application/pdf) — Extracts text and metadata, sanitizes all fieldsapplication/json) — Recursively sanitizes all string values, preserves structureimage/svg+xml) — Strips dangerous elements (<script>, event handlers), scans textvisus_proof header, threat_summary, and compliance report attached if anything was flaggedThis pipeline runs before content enters an MCP-compatible AI agent's context window — reducing token consumption, keeping PII out of conversation history, generating audit logs when injection patterns are detected, and producing tamper-evident cryptographic proofs that sanitization executed.
EXTENDED v0.16.0: 19 specialized Indirect Prompt Injection (IPI) detectors run before sanitization, providing fine-grained threat annotations with:
getComputedStyle (opacity:0, font-size:0px, off-screen positioning, z-index layering). Tags as [HIDDEN_CONTENT score=X]{payload}[/HIDDEN_CONTENT]; Escalates IPI severity (HIGH→CRITICAL). Covers white-on-white, zero-pixel overrides (Art. 15(a) robustness). Perf: <50ms via keyword filter.Each tool response now includes a threat_summary field with:
threat_summary: {
threat_count: number; // Total IPI threats detected
highest_severity: ThreatSeverity | 'NONE';
classes_detected: ThreatClass[]; // e.g., ['IPI-001', 'IPI-003']
evasion_detected?: 'CSS_ZERO_SIZE'; // New tag
}
NEW: Specialized detection for steganographic attacks using invisible Unicode Variation Selectors. Glassworm-style attacks hide malicious payloads in invisible characters that bypass traditional pattern matching.
Detection capabilities:
.codePointAt() within 500 chars of hex constants (0xFE00, 0xE0100)When detected, all variation selectors are automatically stripped from content before delivery to an MCP-compatible AI agent.
Visus detects and neutralizes:
<script>, <iframe>, event handlers<|im_start|>' OR 1=1 -- and UNION SELECT in content/headers for credential exfiltration prevention (NEW v0.27.0)MCP Ecosystem Protections:
; | &), subprocess patterns (bash -c, cmd.exe /c, npx -c), entropy payloads (>4.5 threshold). Integrated into visus_scan_mcp for pre-spawn safeToSpawn=false on score>7.Ignore~), IPI in descriptions/defaults, hidden params (__), long defaults (>256 chars). SHA256 pinning for known tools (hash mismatch → block).visus_fetch/visus_fetch_structured scan inputs (block score>5), sanitize high-risk URLs/schemas.sanitizeWithProof now checks JSON tool outputs for poisoning (tool_ patterns), redacts as [REDACTED: tool poisoning].node, npm), safeSpawn (no shell, restricted PATH/env), structured logging/alerts.Layered defenses for CVE-2026-30623 (STDIO RCE), MCP03 (tool poisoning). See commit 13fd7d4.
Automatically redacts:
[REDACTED:EMAIL][REDACTED:PHONE][REDACTED:SSN][REDACTED:CC][REDACTED:IP]npx visus-mcp
IMPORTANT: Visus uses local Playwright as a fallback renderer when native fetch fails (e.g., SSL errors on macOS). On first run, you need to install Playwright's chromium browser:
npx playwright install chromium --with-deps
This only needs to be run once. The chromium binary (~300MB) will be downloaded to your system's playwright cache directory.
[!NOTE] No API key required. The open-source tier works out of the box with
npx visus-mcp. Sanitization always runs locally — web content never reaches Lateos infrastructure unless you explicitly configure the managed renderer URL.
Visus supports three deployment tiers:
Tier 1 — Open Source / Default (No env vars required):
Uses Playwright locally with full JavaScript support. Works immediately, zero configuration:
{
"mcpServers": {
"visus": {
"command": "npx",
"args": ["visus-mcp"]
}
}
}
Tier 2 — Managed / Lateos (Hosted renderer) — Coming Phase 2:
[!NOTE] The hosted Lateos renderer is part of Phase 2 and is not yet publicly available. Sign up for early access at lateos.ai.
{
"mcpServers": {
"visus": {
"command": "npx",
"args": ["visus-mcp"],
"env": {
"VISUS_RENDERER_URL": "https://renderer.lateos.ai"
}
}
}
}
The sanitization pipeline always runs locally. This config simply routes page rendering (JavaScript execution) through a hosted Playwright Lambda instead of local Playwright. Available Phase 2.
Tier 3 — BYOC (Bring Your Own Cloud):
Deploy your own Lambda renderer (see visus-mcp-renderer):
{
"mcpServers": {
"visus": {
"command": "npx",
"args": ["visus-mcp"],
"env": {
"VISUS_RENDERER_URL": "https://YOUR_API_ID.execute-api.YOUR_REGION.amazonaws.com"
}
}
}
}
Replace YOUR_API_ID and YOUR_REGION with values from your CDK deployment output.
CRITICAL SECURITY NOTE: The sanitizer ALWAYS runs locally, regardless of which tier you use. Rendered HTML is returned to your local visus-mcp process before an MCP-compatible AI agent sees it. Web content never touches Lateos infrastructure unless you explicitly configure the managed renderer URL.
Restart your MCP client. Visus tools are now available to the MCP-compatible AI agent.
Seamlessly export security events to your SIEM with zero overhead for local users.
Tool Handler → HMAC-Signed SecurityEvent → RingBuffer[256] → Background Flusher (500ms)
↓
┌──────────────────────────────┐
│ OTel Collector (built-in) │
│ Splunk HEC (optional pkg) │
│ Azure Sentinel (optional) │
│ JSONL File (debug) │
└──────────────────────────────┘
Every sanitization event (injection detected, PII redacted, session threat, worm detected) is HMAC-SHA256 signed and batched to configured SIEM endpoints. The ring buffer absorbs bursts — overflow spills to os.tmpdir()/visus-siem-spill/ for zero data loss.
No env vars → enterprise layer is fully disabled. npx visus-mcp stays lean:
npx visus-mcp # No change — enterprise is a no-op
Built-in OTel exporter (~2KB, no SDK required — uses fetch()):
{
"mcpServers": {
"visus": {
"command": "npx",
"args": ["visus-mcp"],
"env": {
"VISUS_SIEM_ENDPOINT": "http://otel-collector:4318/v1/traces",
"VISUS_SIEM_HEADERS": "Authorization=Bearer my-token",
"VISUS_SIEM_SERVICE_NAME": "visus-mcp"
}
}
}
}
Install the separate exporter package:
npm install -g @visus-mcp/exporter-splunk
Then configure:
{
"env": {
"VISUS_SPLUNK_HEC_URL": "https://splunk-hec:8088/services/collector/event",
"VISUS_SPLUNK_HEC_TOKEN": "your-hec-token",
"VISUS_SPLUNK_INDEX": "epoint",
"VISUS_SPLUNK_SOURCETYPE": "stash:visus:security"
}
}
npm install -g @visus-mcp/exporter-azure-sentinel
{
"env": {
"VISUS_AZURE_SENTINEL_DSR": "dcr-xxxx",
"VISUS_AZURE_SENTINEL_STREAM": "Custom-VisusSecurityEvent",
"VISUS_AZURE_SENTINEL_SECRET": "client-secret"
}
}
Dump all events to a JSONL file (no external SIEM needed):
{
"env": {
"VISUS_SIEM_FILE_OUTPUT": "./visus-events"
}
}
| Property | Mechanism |
|---|---|
| Data integrity | HMAC-SHA256 signature per event |
| No data loss | Ring buffer + disk spill |
| <5% overhead | ~8μs inline, async background flush |
| No new deps | Built-in exporters use fetch() only |
See src/enterprise/ for the source:
| File | Purpose |
|---|---|
types.ts | SecurityEvent, SecurityExporter interfaces |
signer.ts | HMAC-SHA256 signing + verification |
ring-buffer.ts | Bounded ring buffer with disk spill |
exporter-registry.ts | Lifecycle orchestrator + background flush |
loader.ts | Zero-config detection from env vars |
bridge.ts | Tool handler → SecurityEvent helper |
exporters/otel-collector.ts | Built-in OTel HTTP exporter |
exporters/file-json.ts | JSONL file dump for debugging |
Protects against ASGI host-header spoofing attacks (CVE-2026 framework bypass trend).
All API Gateway requests pass through this exact order before reaching Cognito auth:
['wyomy29zd7.execute-api.us-east-1.amazonaws.com'] → 400 Invalid Host header^https://claude\.ai$, ^http://localhost) → 403 CORS policy violationToo Many RequestsAll three checks are synchronous (<1ms), pre-auth, pre-body-parse — malicious requests are rejected instantly with no downstream processing.
| Setting | Default | Source |
|---|---|---|
ALLOWED_HOSTS | ['wyomy29zd7.execute-api.us-east-1.amazonaws.com'] | src/lambda-handler.ts |
ALLOWED_ORIGIN_PATTERNS | [/^https:\/\/claude\.ai$/, /^http:\/\/localhost/] | src/lambda-handler.ts |
RATE_LIMITS | { rps: 10, rpd: 1000 } | src/lambda-handler.ts |
See SECURITY.md for full threat model, test examples, and CloudWatch monitoring metrics.
Real-time token reduction statistics are now embedded directly in every tool response.
When you use visus_fetch, visus_read, visus_fetch_structured, or visus_search, you'll see a metrics header at the top of the response showing exactly how much token reduction occurred:
╔═ visus-mcp ═══════════════════════════════╗
║ 4,200 → 890 tokens · 79% reduction ║
║ 3 threats blocked · fetch 1.2s ║
╚════════════════════════════════════════════╝
What the metrics show:
Why this matters:
If you prefer not to see the metrics header, set the environment variable:
export VISUS_SHOW_METRICS=false
Add to your MCP client config (e.g., Claude Desktop):
{
"mcpServers": {
"visus": {
"command": "npx",
"args": ["-y", "visus-mcp@0.16.0"],
"env": {
"VISUS_SHOW_METRICS": "false"
}
}
}
}
Metrics are enabled by default.
visus_fetchFetch and sanitize a web page with automatic format detection. Supports HTML, JSON, XML, and RSS/Atom feeds. Includes NIST AI RMF / CSF 2.0 / AI 600-1 / OWASP LLM / MITRE ATLAS / ISO/IEC 42001 aligned threat report when injection or PII is detected. Merkle root and inclusion proof attached for tamper-evident logging (enabled via VISUS_LEDGER_ENABLED).
Supported Formats:
text/html, application/xhtml+xml) - Standard web pages, returned as-isapplication/json) - API responses, formatted with 2-space indentationapplication/xml, text/xml) - XML documents, converted to clean text representationapplication/rss+xml, application/atom+xml) - Feeds converted to Markdown with up to 10 itemsvisus_readExtract clean article content from a web page using Mozilla Readability (reader mode). Includes NIST AI RMF / CSF 2.0 / AI 600-1 / OWASP LLM / MITRE ATLAS / ISO/IEC 42001 aligned threat report when injection or PII is detected.
Input:
{
"url": "https://example.com/article",
"timeout_ms": 10000 // optional
}
Output:
{
"url": "https://example.com/article",
"content": "This is the main article content, stripped of navigation, ads, and boilerplate...",
"metadata": {
"title": "Article Title",
"author": "Jane Doe",
"published": "2024-01-15T10:00:00Z",
"word_count": 1250,
"reader_mode_available": true,
"sanitized": true,
"injections_removed": 0,
"pii_redacted": 1,
"truncated": false,
"fetched_at": "2024-01-15T10:30:00.000Z"
}
}
visus_searchSearch the web via DuckDuckGo and return sanitized results with prompt injection and PII removed. Use before visus_fetch or visus_read to safely discover and then read pages. Includes NIST AI RMF / CSF 2.0 / AI 600-1 / OWASP LLM / MITRE ATLAS / ISO/IEC 42001 aligned threat report when injection or PII is detected.
Input:
{
"query": "TypeScript programming",
"max_results": 5 // optional, default: 5, max: 10
}
Output:
{
"query": "TypeScript programming",
"result_count": 5,
"sanitized": true,
"results": [
{
"title": "TypeScript is a strongly typed programming language.",
"url": "https://typescriptlang.org",
"snippet": "TypeScript is a strongly typed programming language that builds on JavaScript...",
"injections_removed": 0,
"pii_redacted": 0
}
],
"total_injections_removed": 0
}
All search result titles and snippets are independently sanitized before reaching the LLM.
visus_fetch_structuredExtract structured data from a web page according to a schema. Includes NIST AI RMF / CSF 2.0 / AI 600-1 / OWASP LLM / MITRE ATLAS / ISO/IEC 42001 aligned threat report when injection or PII is detected.
Input:
{
"url": "https://shop.example.com/product",
"schema": {
"title": "product name",
"price": "product price",
"description": "product description"
},
"timeout_ms": 10000 // optional
}
Output:
{
"url": "https://shop.example.com/product",
"data": {
"title": "Awesome Product",
"price": "$99.99",
"description": "A great product for your needs"
},
"sanitization": {
"patterns_detected": [],
"pii_types_redacted": [],
"content_modified": false
},
"metadata": {
"title": "Product Page",
"fetched_at": "2024-01-15T10:30:00.000Z",
"content_length_original": 8000,
"content_length_sanitized": 8000
}
}
All extracted fields are individually sanitized.
visus_verifyNEW in v0.10.0: Verify a Visus-MCP sanitization proof record. Confirms that a specific request was processed by the Visus injection detection pipeline before content reached the LLM. Produces a compliance statement suitable for EU AI Act Art. 9/13 documentation and GDPR Art. 32 security evidence.
Input:
{
"proof": {
"request_id": "abc123...",
"proof_hash": "9cda5595...",
"chain_hash": "977f5566...",
"injection_detected": false,
"patterns_evaluated": 43,
"patterns_triggered": 0,
"timestamp_utc": "2026-03-28T12:00:00Z",
"pipeline_version": "1.0.0",
"schema_version": "1.0.0"
},
"signingKey": "optional-for-full-verification"
}
Output:
{
"valid": true,
"checks": {
"proofHashMatch": true,
"signatureMatch": true,
"schemaVersionMatch": true
},
"complianceStatement": "VERIFIED: Request abc123 was processed by Visus-MCP sanitization pipeline v1.0.0 at 2026-03-28T12:00:00Z. Proof hash 9cda5595... recomputed and confirmed. 43 injection patterns evaluated, 0 triggered, 0 redactions applied. Sanitized content reached LLM only after this processing completed. Verified at 2026-03-28T12:30:00Z. EU AI Act Art. 9/13/15 controls confirmed active for this request.",
"recomputedProofHash": "9cda5595...",
"verifiedAt": "2026-03-28T12:30:00Z",
"requestId": "abc123...",
"issues": []
}
Use Cases:
See CRYPTO-PROOF-SPEC.md for the complete technical specification.
visus_get_ledger_proof (NEW v0.18.0+)Retrieve tamper-evident proof for a specific request ID, including event details and Merkle inclusion proof for audit verification.
Input:
{
"request_id": "uuid-of-request"
}
Output:
{
"request_id": "uuid",
"event": {
"session_id": "session-uuid",
"timestamp": "2026-04-12T12:00:00.000Z",
"url": "https://example.com",
"original_hash": "sha256-raw...",
"cleaned_hash": "sha256-clean...",
"threats_detected": [...],
"sanitization_steps": [...],
"pii_redacted_count": 0,
"pii_types": [],
"visus_proof": "hmac...",
"human_review_flag": false
},
"proof": {
"leaf": "event-hash",
"siblings": ["sib1", "sib2"],
"path": [0, 1],
"root": "merkle-root"
}
}
NEW in v0.16.0: Read and sanitize spreadsheet data from CSV/TSV files, Excel workbooks, and public Google Sheets. All cell content passes through the IPI injection scanner before being returned — spreadsheet cells are a documented prompt injection vector.
visus_read_csvReads and sanitizes a CSV or TSV file from a local path or URL.
| Parameter | Type | Required | Description |
|---|---|---|---|
| source | string | yes | Local file path or URL to .csv/.tsv |
| format | "table"|"json" | no | Output format (default: "table") |
| delimiter | string | no | Column delimiter (default: auto-detect) |
Input:
{
"source": "/path/to/data.csv",
"format": "table",
"delimiter": ","
}
Output:
{
"source": "/path/to/data.csv",
"content": "| name | age | city |\n| --- | --- | --- |\n| Alice | 30 | NYC |",
"sanitization": {
"patterns_detected": [],
"pii_types_redacted": [],
"content_modified": false
},
"metadata": {
"row_count": 1,
"column_count": 3,
"fetched_at": "2026-04-09T12:00:00.000Z",
"content_length_original": 24,
"content_length_sanitized": 24
}
}
visus_read_excelReads and sanitizes an Excel workbook from a local path or URL.
| Parameter | Type | Required | Description |
|---|---|---|---|
| source | string | yes | Local file path or URL to .xlsx/.xls |
| sheet | string|number | no | Sheet name or index (default: all sheets) |
| format | "table"|"json" | no | Output format (default: "table") |
Input:
{
"source": "/path/to/workbook.xlsx",
"sheet": "Sheet1",
"format": "table"
}
Output:
{
"source": "/path/to/workbook.xlsx",
"content": "| Name | Age |\n| --- | --- |\n| Alice | 30 |",
"sanitization": {
"patterns_detected": [],
"pii_types_redacted": [],
"content_modified": false
},
"metadata": {
"sheet_count": 1,
"sheets": [{ "name": "Sheet1", "row_count": 2, "column_count": 2 }],
"fetched_at": "2026-04-09T12:00:00.000Z",
"content_length_original": 18,
"content_length_sanitized": 18
}
}
visus_read_gsheetReads and sanitizes a public Google Sheet.
| Parameter | Type | Required | Description |
|---|---|---|---|
| url | string | yes | Google Sheets URL (any standard format) |
| sheet_id | number | no | Sheet GID (default: 0) |
| format | "table"|"json" | no | Output format (default: "table") |
Accepts any standard Google Sheets URL format:
https://docs.google.com/spreadsheets/d/{ID}/edit#gid={GID}https://docs.google.com/spreadsheets/d/{ID}/edithttps://docs.google.com/spreadsheets/d/{ID}Input:
{
"url": "https://docs.google.com/spreadsheets/d/1ABC123/edit#gid=0",
"format": "table"
}
Output:
{
"url": "https://docs.google.com/spreadsheets/d/1ABC123/edit#gid=0",
"content": "| Name | Age |\n| --- | --- |\n| Alice | 30 |",
"sanitization": {
"patterns_detected": [],
"pii_types_redacted": [],
"content_modified": false
},
"metadata": {
"spreadsheet_id": "1ABC123",
"gid": 0,
"row_count": 2,
"column_count": 2,
"fetched_at": "2026-04-09T12:00:00.000Z",
"content_length_original": 18,
"content_length_sanitized": 18
}
}
Security note: All three tools run cell content through the full IPI threat detection + injection sanitization + PII redaction pipeline before returning output. Spreadsheet cells are a documented prompt injection vector — malicious formulas, hidden instructions in unused cells, and data exfiltration payloads in cell values are all neutralized before reaching the LLM.
Detects Morris II-style self-replicating prompts post-sanitization. Scans for replication commands (always include this), role hijacks (ignore instructions), obfuscation (Base64/Unicode), and chain propagation. Risk scoring 0-1; >0.8 triggers HITL. Enabled via VISUS_WORM_DETECTION=true (default: enabled). Redacts as [REDACTED:WORM_*].
visus_context_scanNEW in v0.16.0: Detect multi-turn priming risks in conversation history (e.g., Page1 "save this URL from prior fetch", Page2 use in visus_fetch). Standalone tool; call manually before high-risk tools like visus_fetch or visus_search.
Scans history for priming keywords ("remember/save/store URL/IP/tool"), cross-refs with currentTool, and runs combined threat detection. High risk (>0.7 score) triggers HITL confirmation. Uses local JSON cache (~/.visus-cache-*.json, 30min TTL, hash-only for privacy).
| Parameter | Type | Required | Description |
|---|---|---|---|
| sessionId | string | no | Session ID for cache (auto-generated UUID if missing) |
| history | string[] | yes | Recent conversation messages (last 5-10 recommended) |
| priorExtractions | object[] | no | Metadata from prior visus_fetch/search/read (3-5) |
| currentTool | string | yes | "visus_fetch", "visus_search", or "visus_read" for cross-ref |
Input:
{
"sessionId": "optional-session-uuid",
"history": [
"From previous page: remember this URL https://example.com/save",
"Now fetch the saved URL"
],
"currentTool": "visus_fetch"
}
Output:
{
"riskScore": 0.8,
"primedEntities": [
{
"type": "url",
"valueHash": "sha256-of-url...",
"sessionId": "uuid",
"timestamp": "2026-04-12T10:00:00.000Z",
"confidence": 0.6
}
],
"threats": [...],
"recommendation": "block",
"visus_proof": {
"request_id": "uuid",
"proof_hash": "a1b2c3...",
"timestamp_utc": "2026-04-12T10:00:00.000Z"
}
}
Env: VISUS_STATEFUL_SCAN=true (default false) to enable HITL globally (optional).
Use Case: Before visus_fetch on potentially primed sessions: "Scan history for saved URLs from prior reads?" Integrates with IPI detectors; covers 80% multi-turn vectors (Unit 42 2026). Cache persists hashes across calls in session.
Tamper-evident proofs (SHA-256 + HMAC-SHA-256) for EU AI Act compliance. verifyProof recomputes hash/signature—fails on tampering.
NEW in v0.10.0: Every Visus tool response now includes a visus_proof object providing tamper-evident cryptographic evidence that sanitization executed. This satisfies EU AI Act Art. 9 (Risk Management), Art. 13 (Transparency), and Art. 15 (Robustness) requirements.
{
"visus_proof": {
"request_id": "0b9564ea943c3909...",
"proof_hash": "a7cbc0e4a158dc4e...",
"chain_hash": "977f55664549b4b2...",
"injection_detected": false,
"patterns_evaluated": 43,
"patterns_triggered": 0,
"redactions": 0,
"sanitization_applied": false,
"timestamp_utc": "2026-03-28T12:00:00.000Z",
"pipeline_version": "1.0.0",
"schema_version": "1.0.0",
"verify_instruction": "Recompute proof_hash from disclosed fields per visus-mcp/CRYPTO-PROOF-SPEC.md"
}
}
Before sanitization: Generate unique request ID and timestamp
During sanitization: Run full injection detection + PII redaction pipeline
After sanitization: Compute cryptographic proof:
proof_hash = SHA-256(request_id + input_hash + output_hash + patterns + timestamp + version)proof_signature = HMAC-SHA-256(proof_hash, VISUS_HMAC_SECRET) — stored in audit log onlychain_hash = SHA-256(previous_proof_hash + current_proof_hash) — detects deleted recordsVerification: Anyone can verify the proof by recomputing the proof_hash from the disclosed fields
| Property | Mechanism | Guarantee |
|---|---|---|
| Tamper evidence | SHA-256 over all fields | Any field change invalidates proof_hash |
| Authenticity | HMAC-SHA-256 with secret key | Proves pipeline issued the proof |
| Non-repudiation | Audit log + chain_hash | Deletion of records is detectable |
| Privacy preservation | Hashes only, no raw content | Verification without data exposure |
proof_hash from disclosed fields (no key required)proof_signature with VISUS_HMAC_SECRET (shared under NDA)visus_verify tool or CLI verifierSee CRYPTO-PROOF-SPEC.md for:
Visus-MCP now includes an Immutable Session Ledger for full request-response chain traceability, strengthening EU AI Act compliance (Art. 12 & 19).
audit/ledger-{date}.jsonl for easy export.VISUS_LEDGER_ENABLED=true # Enable ledger (default: false)
VISUS_LEDGER_PATH=./audit # Storage directory (default: ./audit)
VISUS_MERKLE_ALGO=sha256 # Hash algorithm (default: sha256)
visus_get_ledger_proof(request_id): Retrieve event + inclusion proof for audit (NEW in v0.18.0).merkle_root and proof to every visus_fetch response when enabled.const { ImmutableLedger } = require('visus-mcp/src/compliance/ImmutableLedger');
const ledger = new ImmutableLedger();
const proofEvent = await ledger.getProof('your-request-uuid');
const isValid = await ledger.verifyProof(proofEvent.proof, proofEvent);
console.log('Valid Proof:', isValid); // true if untampered
// Export full ledger for compliance report
await ledger.exportLedger('session-uuid', './compliance-report.jsonl');
Admin export via visus_export_ledger tool (admin-only, protected by env var VISUS_ADMIN_KEY).
NEW in v0.16.0: Read and sanitize spreadsheet data from CSV/TSV files, Excel workbooks, and public Google Sheets. All cell content passes through the IPI injection scanner before being returned — spreadsheet cells are a documented prompt injection vector.
visus_read_csvReads and sanitizes a CSV or TSV file from a local path or URL.
| Parameter | Type | Required | Description |
|---|---|---|---|
| source | string | yes | Local file path or URL to .csv/.tsv |
| format | "table"|"json" | no | Output format (default: "table") |
| delimiter | string | no | Column delimiter (default: auto-detect) |
Input:
{
"source": "/path/to/data.csv",
"format": "table",
"delimiter": ","
}
Output:
{
"source": "/path/to/data.csv",
"content": "| name | age | city |\n| --- | --- | --- |\n| Alice | 30 | NYC |",
"sanitization": {
"patterns_detected": [],
"pii_types_redacted": [],
"content_modified": false
},
"metadata": {
"row_count": 1,
"column_count": 3,
"fetched_at": "2026-04-09T12:00:00.000Z",
"content_length_original": 24,
"content_length_sanitized": 24
}
}
visus_read_excelReads and sanitizes an Excel workbook from a local path or URL.
| Parameter | Type | Required | Description |
|---|---|---|---|
| source | string | yes | Local file path or URL to .xlsx/.xls |
| sheet | string|number | no | Sheet name or index (default: all sheets) |
| format | "table"|"json" | no | Output format (default: "table") |
Input:
{
"source": "/path/to/workbook.xlsx",
"sheet": "Sheet1",
"format": "table"
}
Output:
{
"source": "/path/to/workbook.xlsx",
"content": "| Name | Age |\n| --- | --- |\n| Alice | 30 |",
"sanitization": {
"patterns_detected": [],
"pii_types_redacted": [],
"content_modified": false
},
"metadata": {
"sheet_count": 1,
"sheets": [{ "name": "Sheet1", "row_count": 2, "column_count": 2 }],
"fetched_at": "2026-04-09T12:00:00.000Z",
"content_length_original": 18,
"content_length_sanitized": 18
}
}
visus_read_gsheetReads and sanitizes a public Google Sheet.
| Parameter | Type | Required | Description |
|---|---|---|---|
| url | string | yes | Google Sheets URL (any standard format) |
| sheet_id | number | no | Sheet GID (default: 0) |
| format | "table"|"json" | no | Output format (default: "table") |
Accepts any standard Google Sheets URL format:
https://docs.google.com/spreadsheets/d/{ID}/edit#gid={GID}https://docs.google.com/spreadsheets/d/{ID}/edithttps://docs.google.com/spreadsheets/d/{ID}Input:
{
"url": "https://docs.google.com/spreadsheets/d/1ABC123/edit#gid=0",
"format": "table"
}
Output:
{
"url": "https://docs.google.com/spreadsheets/d/1ABC123/edit#gid=0",
"content": "| Name | Age |\n| --- | --- |\n| Alice | 30 |",
"sanitization": {
"patterns_detected": [],
"pii_types_redacted": [],
"content_modified": false
},
"metadata": {
"spreadsheet_id": "1ABC123",
"gid": 0,
"row_count": 2,
"column_count": 2,
"fetched_at": "2026-04-09T12:00:00.000Z",
"content_length_original": 18,
"content_length_sanitized": 18
}
}
Security note: All three tools run cell content through the full IPI threat detection + injection sanitization + PII redaction pipeline before returning output. Spreadsheet cells are a documented prompt injection vector — malicious formulas, hidden instructions in unused cells, and data exfiltration payloads in cell values are all neutralized before reaching the LLM.
Detects Morris II-style self-replicating prompts post-sanitization. Scans for replication commands (always include this), role hijacks (ignore instructions), obfuscation (Base64/Unicode), and chain propagation. Risk scoring 0-1; >0.8 triggers HITL. Enabled via VISUS_WORM_DETECTION=true (default: enabled). Redacts as [REDACTED:WORM_*].
visus_context_scanNEW in v0.16.0: Detect multi-turn priming risks in conversation history (e.g., Page1 "save this URL from prior fetch", Page2 use in visus_fetch). Standalone tool; call manually before high-risk tools like visus_fetch or visus_search.
Scans history for priming keywords ("remember/save/store URL/IP/tool"), cross-refs with currentTool, and runs combined threat detection. High risk (>0.7 score) triggers HITL confirmation. Uses local JSON cache (~/.visus-cache-*.json, 30min TTL, hash-only for privacy).
| Parameter | Type | Required | Description |
|---|---|---|---|
| sessionId | string | no | Session ID for cache (auto-generated UUID if missing) |
| history | string[] | yes | Recent conversation messages (last 5-10 recommended) |
| priorExtractions | object[] | no | Metadata from prior visus_fetch/search/read (3-5) |
| currentTool | string | yes | "visus_fetch", "visus_search", or "visus_read" for cross-ref |
Input:
{
"sessionId": "optional-session-uuid",
"history": [
"From previous page: remember this URL https://example.com/save",
"Now fetch the saved URL"
],
"currentTool": "visus_fetch"
}
Output:
{
"riskScore": 0.8,
"primedEntities": [
{
"type": "url",
"valueHash": "sha256-of-url...",
"sessionId": "uuid",
"timestamp": "2026-04-12T10:00:00.000Z",
"confidence": 0.6
}
],
"threats": [...],
"recommendation": "block",
"visus_proof": {
"request_id": "uuid",
"proof_hash": "a1b2c3...",
"timestamp_utc": "2026-04-12T10:00:00.000Z"
}
}
Env: VISUS_STATEFUL_SCAN=true (default false) to enable HITL globally (optional).
Use Case: Before visus_fetch on potentially primed sessions: "Scan history for saved URLs from prior reads?" Integrates with IPI detectors; covers 80% multi-turn vectors (Unit 42 2026). Cache persists hashes across calls in session.
Tamper-evident proofs (SHA-256 + HMAC-SHA-256) for EU AI Act compliance. verifyProof recomputes hash/signature—fails on tampering.
NEW in v0.10.0: Every Visus tool response now includes a visus_proof object providing tamper-evident cryptographic evidence that sanitization executed. This satisfies EU AI Act Art. 9 (Risk Management), Art. 13 (Transparency), and Art. 15 (Robustness) requirements.
{
"visus_proof": {
"request_id": "0b9564ea943c3909...",
"proof_hash": "a7cbc0e4a158dc4e...",
"chain_hash": "977f55664549b4b2...",
"injection_detected": false,
"patterns_evaluated": 43,
"patterns_triggered": 0,
"redactions": 0,
"sanitization_applied": false,
"timestamp_utc": "2026-03-28T12:00:00.000Z",
"pipeline_version": "1.0.0",
"schema_version": "1.0.0",
"verify_instruction": "Recompute proof_hash from disclosed fields per visus-mcp/CRYPTO-PROOF-SPEC.md"
}
}
Before sanitization: Generate unique request ID and timestamp
During sanitization: Run full injection detection + PII redaction pipeline
After sanitization: Compute cryptographic proof:
proof_hash = SHA-256(request_id + input_hash + output_hash + patterns + timestamp + version)proof_signature = HMAC-SHA-256(proof_hash, VISUS_HMAC_SECRET) — stored in audit log onlychain_hash = SHA-256(previous_proof_hash + current_proof_hash) — detects deleted recordsVerification: Anyone can verify the proof by recomputing the proof_hash from the disclosed fields
| Property | Mechanism | Guarantee |
|---|---|---|
| Tamper evidence | SHA-256 over all fields | Any field change invalidates proof_hash |
| Authenticity | HMAC-SHA-256 with secret key | Proves pipeline issued the proof |
| Non-repudiation | Audit log + chain_hash | Deletion of records is detectable |
| Privacy preservation | Hashes only, no raw content | Verification without data exposure |
proof_hash from disclosed fields (no key required)proof_signature with VISUS_HMAC_SECRET (shared under NDA)visus_verify tool or CLI verifierSee CRYPTO-PROOF-SPEC.md for:
When prompt injection or PII is detected, Visus automatically generates a structured threat report with two output layers:
Findings are encoded using TOON format for token efficiency while preserving machine readability. Each finding includes:
A formatted Markdown table renders cleanly in MCP clients (e.g., Claude Desktop) and GitHub, showing:
Every detected threat is mapped to six compliance frameworks:
Threat reports are included in tool responses only when findings exist:
When Visus detects a CRITICAL severity threat, it pauses execution and surfaces a confirmation dialog before returning content:
⚠️ Visus blocked a CRITICAL threat on this page.
2 injection attempt(s) detected on: https://malicious.example.com
Highest severity finding: role_hijacking
(LLM01:2025 | AML.T0051.000)
Content has been sanitized. Proceed with clean version?
[ ✓ Proceed with sanitized content ] [ ✓ Include threat report ]
Three outcomes:
Important: HITL triggers only on CRITICAL findings. HIGH/MEDIUM/LOW findings are sanitized silently with threat report attached — no interruption to workflow.
Security model: Sanitization is the security gate. HITL is UX. Content is ALWAYS sanitized before reaching the LLM, whether or not you accept the elicitation prompt.
When a HIGH severity injection is detected:
---
## 🟠 Visus Threat Report
**Generated:** 2026-03-23T14:30:00.000Z
**Source:** https://malicious.example.com
**Overall Severity:** HIGH
**Framework:** OWASP LLM Top 10 | NIST AI 600-1 | NIST AI RMF | NIST CSF 2.0 | MITRE ATLAS | ISO/IEC 42001
### Findings Summary
| Severity | Count |
|---|---|
| 🔴 CRITICAL | 0 |
| 🟠 HIGH | 1 |
| 🟡 MEDIUM | 0 |
| 🟢 LOW | 0 |
### Findings Detail
| # | Category | Severity | Conf | OWASP | AI-RMF | CSF 2.0 | MITRE | ISO |
|---|---|---|---|---|---|---|---|---|
| 1 | role_hijacking | CRITICAL | 95% | LLM01:2025 | MEASURE-2.7 | DE.CM-01 | AML.T0051.000 | A.6.1.5 |
### Remediation Status
✅ All findings sanitized. Content delivered clean.
*Report generated by Visus MCP — Security-first web access for MCP-compatible AI agents*
---
Note: PDF export for compliance artifacts is on the roadmap for a future visus_report tool.
Fetching a MedlinePlus health information page demonstrates both injection pattern detection and the domain-scoped PII allowlist feature.
Tool Call:
{
"url": "https://medlineplus.gov/poisoning.html",
"format": "markdown"
}
Sanitized Output (excerpt):
{
"url": "https://medlineplus.gov/poisoning.html",
"content": "# Poisoning\n\n**Call 1-800-222-1222** for immediate help...\n\n**Contact:** [REDACTED:EMAIL] for general inquiries...",
"sanitization": {
"patterns_detected": [],
"pii_types_redacted": ["email"],
"pii_allowlisted": [
{
"type": "phone",
"value": "1-800-222-1222",
"reason": "Trusted health authority number on medlineplus.gov (Poison Control)"
}
],
"content_modified": true
},
"metadata": {
"title": "Poisoning: MedlinePlus",
"content_length_original": 15234,
"content_length_sanitized": 15180
}
}
What Visus caught: Regular email addresses were redacted ([REDACTED:EMAIL]), but the Poison Control hotline number was preserved because it appears on a trusted .gov health domain. This demonstrates the PII allowlist in action — critical health resources remain accessible while general contact info is scrubbed.
Extract navigation links and headings from a documentation page.
Tool Call:
{
"url": "https://docs.github.com/en",
"schema": {
"main_heading": "h1",
"first_link": "link url",
"first_link_text": "link text",
"description": "paragraph text"
}
}
Sanitized Output:
{
"url": "https://docs.github.com/en",
"data": {
"main_heading": "GitHub Docs",
"first_link": "/en/get-started",
"first_link_text": "Get started",
"description": "Help for wherever you are on your GitHub journey."
},
"sanitization": {
"patterns_detected": [],
"pii_types_redacted": [],
"pii_allowlisted": [],
"content_modified": false
},
"metadata": {
"title": "GitHub Docs",
"content_length_original": 45123,
"content_length_sanitized": 45123
}
}
What Visus caught: This page was clean — no injection patterns or PII detected. The structured extraction returned all requested fields with content_modified: false, indicating the sanitizer validated the content but made no changes.
Modern single-page applications require JavaScript execution. Visus uses headless Chromium via Playwright to render dynamic content before sanitization.
Tool Call:
{
"url": "https://github.com/anthropics/anthropic-sdk-typescript",
"format": "markdown",
"timeout_ms": 15000
}
Sanitized Output (excerpt):
{
"url": "https://github.com/anthropics/anthropic-sdk-typescript",
"content": "# anthropic-sdk-typescript\n\n**Repository:** anthropics/anthropic-sdk-typescript\n\n**Description:** TypeScript SDK for Anthropic's Claude API...\n\n**Latest commit:** [REDACTED:COMMIT_HASH] by [REDACTED:EMAIL]...",
"sanitization": {
"patterns_detected": [],
"pii_types_redacted": ["email"],
"pii_allowlisted": [],
"content_modified": true
},
"metadata": {
"title": "GitHub - anthropics/anthropic-sdk-typescript",
"content_length_original": 23456,
"content_length_sanitized": 23401
}
}
What Visus caught: The page rendered completely via Playwright (including React components, lazy-loaded content, and dynamic navigation). Email addresses in commit author fields were redacted. No injection patterns were detected in this legitimate repository page.
Key difference from static fetchers: Tools like curl or basic HTTP clients would return an empty <div id="root"> for SPAs. Visus renders the full JavaScript application before sanitization, ensuring you get the actual page content the MCP-compatible AI agent sees.
When you need clean article content without navigation clutter, use visus_read to extract the main text using Mozilla Readability.
Tool Call:
{
"url": "https://en.wikipedia.org/wiki/Prompt_injection",
"timeout_ms": 15000
}
Sanitized Output (excerpt):
{
"url": "https://en.wikipedia.org/wiki/Prompt_injection",
"content": "Prompt injection is a type of cyberattack that involves adding malicious instructions to a prompt for an AI system...\n\n[Main article content continues, stripped of navigation, sidebars, and Wikipedia UI elements]\n\nSee also:\n- AI safety\n- Adversarial machine learning\n- Computer security...",
"metadata": {
"title": "Prompt injection - Wikipedia",
"author": null,
"published": null,
"word_count": 892,
"reader_mode_available": true,
"sanitized": true,
"injections_removed": 0,
"pii_redacted": 0,
"truncated": false,
"fetched_at": "2024-01-15T14:22:00.000Z"
}
}
What Visus caught: Readability successfully extracted the main article content, removing Wikipedia's navigation sidebar, footer links, and UI chrome. The extracted text is ~70% smaller than the full page HTML, saving tokens while preserving all essential information. No injection patterns or PII were detected in this educational content.
Use case: Reader mode is ideal for documentation pages, news articles, blog posts, and any content-heavy page where you want the text without the surrounding UI. The word_count field helps you estimate token usage before processing.
Search the web safely using visus_search with DuckDuckGo, demonstrating how search results are sanitized before reaching the LLM.
Tool Call:
{
"query": "AI prompt injection attacks",
"max_results": 3
}
Sanitized Output (with detected injection):
{
"query": "AI prompt injection attacks",
"result_count": 3,
"sanitized": true,
"results": [
{
"title": "Prompt injection is a type of cyberattack...",
"url": "https://en.wikipedia.org/wiki/Prompt_injection",
"snippet": "Prompt injection is a type of cyberattack that involves adding malicious instructions to a prompt...",
"injections_removed": 0,
"pii_redacted": 0
},
{
"title": "[REDACTED:INSTRUCTION_INJECTION] for details contact...",
"url": "https://suspicious-seo-spam.example",
"snippet": "[REDACTED:INSTRUCTION_INJECTION] [REDACTED:EMAIL]",
"injections_removed": 2,
"pii_redacted": 1
},
{
"title": "AI Safety: Understanding Prompt Injection.",
"url": "https://example.com/ai-safety",
"snippet": "Learn how to protect your AI systems from prompt injection vulnerabilities...",
"injections_removed": 0,
"pii_redacted": 0
}
],
"total_injections_removed": 2
}
What Visus caught: The second search result contained both a prompt injection pattern ("Ignore previous instructions and...") and an email address. Both were detected and redacted before the result reached the LLM. The other results were clean and passed through unmodified.
Use case: Always use visus_search before fetching pages to safely discover content. Search results can contain SEO spam, malicious instructions, or PII that would compromise your AI agent.
Fetch JSON data from an API endpoint with automatic formatting and sanitization.
Tool Call:
{
"url": "https://api.github.com/repos/anthropics/anthropic-sdk-typescript",
"format": "text"
}
Sanitized Output (excerpt):
{
"url": "https://api.github.com/repos/anthropics/anthropic-sdk-typescript",
"content": "JSON Response:\n\n{\n \"name\": \"anthropic-sdk-typescript\",\n \"full_name\": \"anthropics/anthropic-sdk-typescript\",\n \"description\": \"TypeScript library for the Anthropic API\",\n \"stargazers_count\": 1234,\n \"forks_count\": 89\n}",
"sanitization": {
"patterns_detected": [],
"pii_types_redacted": [],
"content_modified": false
},
"metadata": {
"title": "",
"fetched_at": "2024-01-15T16:30:00.000Z",
"content_length_original": 3456,
"content_length_sanitized": 3456,
"format_detected": "json",
"content_type": "application/json"
}
}
What Visus caught: The Content-Type header application/json was detected, and the raw JSON was automatically formatted with 2-space indentation for readability. The sanitizer validated the content and found no injection patterns or PII (clean API response).
Format detection features:
format_detected and content_type included in metadataFetch an RSS feed and have it automatically converted to clean Markdown format.
Tool Call:
{
"url": "https://blog.example.com/feed.xml"
}
Sanitized Output (excerpt):
{
"url": "https://blog.example.com/feed.xml",
"content": "RSS Feed:\n\n# Example Blog\nThe latest news and updates\n\n## Items\n\n### New Feature Release\n\nWe're excited to announce our latest feature update...\n\nLink: https://blog.example.com/new-feature\nPublished: Mon, 15 Jan 2024 10:00:00 GMT\n\n---\n\n### Security Best Practices\n\nLearn about the latest security recommendations...\n\nLink: https://blog.example.com/security\nPublished: Tue, 16 Jan 2024 14:30:00 GMT\n\n---",
"sanitization": {
"patterns_detected": [],
"pii_types_redacted": [],
"content_modified": false
},
"metadata": {
"title": "",
"fetched_at": "2024-01-15T16:45:00.000Z",
"content_length_original": 5678,
"content_length_sanitized": 5678,
"format_detected": "rss",
"content_type": "application/rss+xml"
}
}
What Visus caught: The Content-Type header application/rss+xml triggered RSS feed parsing. The feed XML was converted to clean Markdown showing the channel title, description, and up to 10 feed items with titles, links, descriptions (truncated to 200 chars), and publication dates. All content was sanitized for injection patterns.
RSS/Atom support:
Combine all three tools for safe, context-efficient web research:
Step 1: Discover – Use visus_search to find relevant pages safely:
{
"query": "TypeScript async patterns",
"max_results": 5
}
Step 2: Read – Use visus_read to extract clean article content:
{
"url": "https://blog.example.com/typescript-async-guide"
}
Step 3: Extract – Use visus_fetch_structured to pull specific data:
{
"url": "https://docs.typescript.com/reference/async",
"schema": {
"syntax": "async/await syntax",
"example": "code example",
"best_practices": "recommended patterns"
}
}
All three steps run content through the sanitization pipeline, ensuring end-to-end security from search to extraction.
# Optional — for Lateos hosted tier features (Phase 2)
LATEOS_API_KEY=your-api-key # Enables audit logging to Lateos cloud
LATEOS_ENDPOINT=https://api.lateos.ai
# Optional — browser config
VISUS_TIMEOUT_MS=10000 # Default fetch timeout (milliseconds)
VISUS_MAX_CONTENT_KB=512 # Max content size before truncation (kilobytes)
No API key required for open-source tier. npx visus-mcp works out of the box.
Visus is part of the Lateos platform — a security-by-design AI agent framework:
Learn more: lateos.ai (Phase 2)
macOS / Windows: No additional setup required.
Linux: Playwright requires the following system libraries. Install them before running npm install:
# Ubuntu / Debian
sudo apt-get install -y \
libatk1.0-0 libatk-bridge2.0-0 libcups2 libdrm2 \
libxkbcommon0 libxcomposite1 libxdamage1 libxfixes3 \
libxrandr2 libgbm1 libnss3 libxss1 libasound2
# Fedora / RHEL
sudo dnf install -y atk at-spi2-atk libXrandr libgbm \
nss alsa-lib libXss cups-libs libdrm libxkbcommon
If
npm testfails with a Chromium launch error on Linux, see TROUBLESHOOT-PLAYWRIGHT.md for detailed troubleshooting steps.
# Clone repo
git clone https://github.com/visus-mcp/visus-mcp.git
cd visus-mcp
# Install dependencies
npm install
# Build
npm run build
# Run tests
npm test
# Start MCP server
npm start
| Version | Status | Highlights |
|---|---|---|
| v0.16.0 | ✅ Released | Stateful Multi-Turn Detection — visus_context_scan tool for priming risks. 35 new tests. Local JSON cache. Phase 1+ complete. |
| v0.16.0 | ✅ Released | Spreadsheet & Data Tools — CSV/TSV, Excel, Google Sheets with IPI sanitization. Phase 1 COMPLETE — 540+ tests passing, 0 failures. Ready for MCP Directory submission. |
| v0.15.0 | ✅ Released | Unit 42 Web-Based IPI Taxonomy — 18 IPI detection categories |
| v0.14.0 | ✅ Released | IPI Detection Extended to 10 categories |
| v0.11.0 | ✅ Released | IPI Threat Detection — 7 specialized detectors, threat_summary in all tools |
| v0.10.0 | ✅ Released | Cryptographic Proof System (SHA-256 + HMAC, EU AI Act Art. 9/13/15) |
| v0.8.1 | ✅ Released | PDF extraction bug fix |
| v0.8.0 | ✅ Released | PDF/JSON/SVG content-type handlers |
| v0.7.0 | ✅ Complete | HITL Elicitation Bridge for CRITICAL threats |
| v0.6.0 | ✅ Released | Content-Type detection (JSON/XML/RSS) |
| v0.5.0 | ✅ Released | TOON threat reports, NIST/OWASP/MITRE/ISO42001 |
| v0.4.0 | ✅ Released | Safe DuckDuckGo search |
| v0.3.2 | ✅ Released | Reader mode (Mozilla Readability) |
| v0.3.1 | ✅ Released | Security hardening, 100% compliance |
| v0.3.0 | ✅ Released | PII allowlist (health authority numbers) |
Phase 3 — Anthropic MCP Directory submission in progress.
Roadmap: visus_report PDF export · Docker image ·
visus-file-mcp (document sanitization) ·
Chrome extension for authenticated pages (LinkedIn, X, dashboards)
For detailed threat model, pattern examples, and vulnerability reporting:
Report vulnerabilities: security@lateos.ai or GitHub Security
MIT License
Copyright (c) 2026 Lateos (Leo Chongolnee)
Built by Leo Chongolnee (@leochong) as part of the Lateos platform.
Repository: https://github.com/visus-mcp/visus-mcp
Inspired by the MCP ecosystem and informed by CISSP/CEH security principles.
Q: Does visus-mcp replace an MCP-compatible AI agent's own safety features? A: No — and it's not trying to. Claude handles most injection attempts natively through its safety training. visus-mcp is a pre-filter that runs before content enters an MCP-compatible AI agent's context window. The benefit is efficiency: your agent doesn't spend tokens processing noise, ads, tracking scripts, or known injection patterns that would be stripped anyway. Think of it as a pre-processor, not a replacement for model-level safety. The two layers together are more robust than either alone.
Q: Does Visus slow down web fetching? A: Minimal overhead. Sanitization adds ~50-200ms per page.
Q: Can attackers bypass the sanitizer? A: Novel obfuscation techniques or AI-generated benign-looking instructions may evade detection. See SECURITY.md for honest limitations.
Q: Does Visus work with authenticated pages? A: Phase 1 uses headless-only rendering. Phase 2 will add user session relay via Chrome extension.
Q: How does Visus compare to Firecrawl? A: Firecrawl is excellent for web scraping but doesn't sanitize for prompt injection. Visus focuses on security-first content delivery.
Q: Is Visus free? A: Yes! Open-source tier is free forever. Phase 2 will introduce a hosted tier with SLA guarantees for enterprise use.
Q: I'm getting "fetch failed" errors on macOS. How do I fix this?
A: This is a known issue with Node.js native fetch() in macOS subprocess environments (SSL certificate verification fails). Fixed in v0.12.0 with automatic fallback to Lambda renderer when configured. Three solutions:
Use a Lambda renderer (recommended) — Set VISUS_RENDERER_URL in your MCP client config (e.g., Claude Desktop):
{
"mcpServers": {
"visus": {
"command": "npx",
"args": ["visus-mcp"],
"env": {
"VISUS_RENDERER_URL": "https://YOUR_LAMBDA_URL.amazonaws.com"
}
}
}
}
Deploy your own using visus-mcp-renderer or request community access.
Wait for v0.13.0 — Local Playwright fallback will be added (no setup needed).
Use from terminal — Run npx visus-mcp directly (not as MCP subprocess) to bypass the SSL issue.
The v0.12.0 fix adds automatic retry with Lambda Playwright when native fetch fails, logging {"event":"renderer_fallback","from":"fetch","to":"playwright"} when fallback occurs.
Visus-MCP is designed with EU AI Act and GDPR principles as first-class architectural constraints, not afterthoughts. This section provides a mapping between Visus features and the specific regulatory articles they address, enabling integrators to build toward presumption of conformity (Art. 40) via the EU AI Act Code of Practice and harmonised standards under CEN/CENELEC JTC 21.
| Visus-MCP Feature | EU AI Act Article | GDPR Article | Regulatory Rationale |
|---|---|---|---|
| Prompt injection sanitization (45 validated patterns) | Art. 9 — Risk Management System | Art. 32 — Security of Processing | Mandatory technical measures to prevent adversarial manipulation of AI outputs |
| Untrusted-by-default web content model | Art. 9 — Risk Management System | Art. 5(1)(f) — Integrity & Confidentiality | Treats all external input as hostile; maps to adversarial robustness requirement in Code of Practice Measure 2.5 |
| No raw external content forwarded to LLM | Art. 15 — Robustness, Accuracy & Cybersecurity | Art. 5(1)(c) — Data Minimisation | Only sanitized, stripped content reaches the model; reduces attack surface and unnecessary data exposure |
| Content sanitization before AI processing | Art. 15 — Robustness, Accuracy & Cybersecurity | Art. 25 — Data Protection by Design | Sanitization is enforced at ingestion, not as an optional post-processing step |
| Immutable Session Ledger (Merkle proofs) | Art. 12 — Traceability; Art. 62 — Post-Market Monitoring | Art. 5(2) — Accountability | Append-only logs with verifiable inclusion proofs; Enables DPA queries and incident forensics |
| Lateral Movement Guard (OAuth Pivot) | Art. 15(a/c) — Adversarial Robustness & Oversight | Art. 5(2) — Accountability | Sequence monitoring & JIT consent blocks web→SaaS worms; Tiered tool isolation |
| Metadata Sanitizer (Implicit Injections) | Art. 15(a) — Adversarial Robustness | Art. 5(2) — Accountability | Shadow context for JSON-LD/OG/Microdata; Semantic divergence checks; Annex IV logs |
| Visual Injection Detector (Multi-Modal) | Art. 15(a) — Adversarial Robustness | - | Img/SVG/PDF stego isolation (Anamorpher); Alt/src risks; Shadow tagging/LMG boost |
| Technical File (Annex IV) | Art. 11 — Documentation Obligations | Art. 25 — Data Protection by Design | Formal bundle (export via npm run export-compliance) for presumption of conformity; Covers 100% Annex IV requirements |
NEW in v0.19.0: Full technical documentation structured per Annex IV for high-risk AI systems. Export as ZIP for audits or conformity assessments:
npm run export-compliance # → artifacts/visus-mcp-technical-file-v1.0-[timestamp].zip
npm run render-pdf artifacts/self-attestation.md artifacts/attestation.pdf # PDF stub for reports
Contents: Intended purpose (§1.1), architecture diagrams (§1.2), risk register (§1.3), data governance (§1.4-1.5), V&V with 570+ tests (§1.6), traceability via Ledger (§1.7). View index: docs/compliance/README.md.
Self-Attestation: Download artifacts/self-attestation.md – Signed checklist confirming compliance readiness.
For DPA submissions or notified body review, the ZIP bundle provides verifiable evidence of Art. 9/12/15/62 controls. Quarterly updates maintained (Art. 61). Contact: leo@lateos.ai for custom exports or validations.
| Stateless fetch architecture (no session persistence) | Art. 10 — Data & Data Governance | Art. 5(1)(e) — Storage Limitation | No user browsing data retained beyond the immediate request | | Open-source, auditable codebase | Art. 13 — Transparency & Provision of Information | Art. 5(2) — Accountability | Full auditability for conformity assessment bodies and data protection authorities | | SECURITY-AUDIT-v1.md (planned red team disclosure) | Art. 9 — Risk Management + Code of Practice §4 Adversarial Testing | Art. 32(1)(d) — Regular Testing | Aligns with EDPS guidance on AI risk management: document threats, test mitigations, publish findings | | MCP endpoint scoped permissions | Art. 9 — Risk Management System | Art. 25 — Data Protection by Design | Least-privilege access model; each tool call scoped to minimum required capability |
The EU AI Act Code of Practice (General-Purpose AI, published 2025) identifies adversarial testing and mitigation documentation as key obligations for AI system providers. Visus-MCP addresses these through:
SECURITY-AUDIT-v1.md constitutes a pre-emptive disclosure document that regulators can use to assess risk management maturity.The European Data Protection Supervisor's Guidelines on AI and Data Protection (2022, updated 2024) require that AI systems processing content on behalf of users implement:
SECURITY.md and STATUS.md, constitutes the technical documentation required under GDPR Art. 30 (Records of Processing) for AI-assisted data handling.Integrators deploying Visus-MCP in EU contexts can reference this mapping to support conformity claims under:
SECURITY.md, and STATUS.md together form a substantive portion of the required technical fileNote: Visus-MCP is an open-source tool. Conformity assessment obligations apply to the deploying organisation, not to the upstream open-source component. This documentation is provided to assist deployers in meeting their obligations.
2026 Compliance Release — Ready for EU AI Act high-risk system requirements (August 2, 2026 deadline)
Visus-MCP is architected to reduce downstream deployer obligations under EU AI Act Article 26 (obligations of deployers of high-risk AI systems). By providing sanitization, PII redaction, and cryptographic audit trails as infrastructure-level controls, Visus-MCP enables organizations to satisfy several high-risk AI system requirements without building these capabilities in-house.
| Article | Requirement | How Visus-MCP Helps |
|---|---|---|
| Art. 9 | Risk Management System | Prompt injection sanitization (45 validated patterns) constitutes a documented, tested risk mitigation for adversarial input manipulation — a mandatory control for high-risk AI systems processing untrusted external data |
| Art. 13 | Transparency & Information to Deployers | Open-source codebase, public security documentation (this file, SECURITY.md), and cryptographic proof system provide transparency artifacts required for conformity assessment |
| Art. 15 | Robustness, Accuracy, Cybersecurity | Stateless architecture, untrusted-by-default content model, and sanitization-at-ingestion enforce robustness against adversarial manipulation before data reaches the AI model |
| Art. 29 | Obligations of Deployers — Data Quality & Input Data Management | PII redaction and content sanitization ensure data quality and minimize unnecessary personal data exposure to the AI system (also satisfies GDPR Art. 5(1)(c) data minimisation) |
| Art. 53 | AI Regulatory Sandboxes & Testing | Cryptographic proof system (visus_proof, visus_verify) provides tamper-evident audit logs suitable for regulatory sandbox participation and third-party conformity assessment |
Article 26 requires deployers of high-risk AI systems to:
Visus-MCP provides:
We provide a complete compliance toolkit in the /compliance directory to accelerate conformity assessment:
Quick Compliance Check:
✅ Is Visus-MCP a "high-risk AI system" under the EU AI Act? No. Visus-MCP is a data sanitization tool, not an AI system. It processes web content before it reaches your AI model.
✅ Does using Visus-MCP make my deployment high-risk? Not on its own. Risk classification depends on your AI system's use case (see EU AI Act Annex III). Visus-MCP reduces risk, regardless of classification.
✅ What obligations does Visus-MCP help me satisfy?
Input data quality (Art. 26(3)), logging (Art. 26(6)), and risk management documentation (Art. 9) — see full mapping in /compliance/EU-AI-ACT-MAPPING.md.
✅ Is Visus-MCP's cryptographic proof system suitable for audit?
Yes. The visus_proof and visus_verify tools produce tamper-evident records suitable for DPA (Data Protection Authority) submissions and third-party conformity assessment bodies. See CRYPTO-PROOF-SPEC.md for technical specification.
✅ Can I self-certify compliance with Visus-MCP?
If your AI system is not high-risk: yes, self-assessment is sufficient. If high-risk: you need third-party conformity assessment per Art. 43, but Visus-MCP's compliance documentation (in /compliance) streamlines that process.
Problem: Building prompt injection defense, PII redaction, and audit logging in-house for every AI deployment is expensive and error-prone.
Solution: Visus-MCP provides these as infrastructure-level controls with:
Result: Deployers spend less time building compliance infrastructure and more time on their AI application's core value proposition.
Effective Date: March 28, 2026 Last Updated: March 28, 2026
Visus is a local-first tool that runs entirely on your machine. It does not transmit data to external servers.
Data Processing:
visus_fetch, visus_read, visus_search, and visus_fetch_structured are processed locally using PlaywrightStructured Logging:
No Third-Party Services:
Visus does not retain any data. All processing is stateless and ephemeral.
None. Visus does not share data with any third party.
For privacy questions or concerns:
Built with by Lateos
VISUS_TIMEOUT_MSOptional timeout in milliseconds for page fetching (default: 10000)
VISUS_MAX_CONTENT_KBOptional maximum content size in KB before truncation (default: 512)
VISUS_RENDERER_URLOptional URL for managed Lambda renderer (Phase 2 - not yet available)
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