Vouqis

MCP failures often look like success.

HTTP 200 does not mean the tool worked. Vouqis sits between your AI agent and MCP servers, blocking silent failures before they reach production.

Agent → Vouqis → MCP Server

Website · Live Gateway · Founding Customer (3 months free) · Issues

The Problem

HTTP 200 is not success for MCP. Your AI agent calls a tool, gets a 200, logs "success" — and your user sees nothing happen.

Without Vouqis:
  Agent → MCP Server → result: null → Agent says "done" → silent failure

With Vouqis:
  Agent → Vouqis → MCP Server → result: null → Vouqis blocks → Agent gets an error it can handle

These are real documented incidents where servers returned 200 while broken:

HTTP 200 with empty content
Null responses
Invalid schemas
Partial results
Hung requests that never resolve

Standard monitoring stays green. Your agent believes the task succeeded. Your user receives a broken outcome.

The Gateway

vouqis proxy is the core product. It sits between your agent and every MCP server. Point your agent at localhost:4444 instead of the upstream. Every call is validated, timed, and logged.

Quick Start

Install:

npm install -g @vouqis/cli

Start the gateway:

vouqis proxy --upstream https://your-mcp-server.com

VOUQIS ── proxy ── https://your-mcp-server.com

  Listening on   http://127.0.0.1:4444
  Upstream       https://your-mcp-server.com
  Timeout        5000ms
  Retry          1 (idempotent requests)
  Block null     yes
  Audit log      ./vouqis-audit.log

  Point your agent at http://127.0.0.1:4444 instead of the real server.

  [14:23:11]  ALLOW    tools/call    list_repos          142ms
  [14:23:19]  ALLOW    tools/call    search_code         388ms
  [14:23:31]  RETRY    tools/call    get_file            5003ms  ← timeout on attempt 1
  [14:23:36]  ALLOW    tools/call    get_file            411ms
  [14:23:44]  BLOCK    tools/call    search              0ms     ← tools/call content is empty

The only change to your agent is the URL:

// Before
const client = new MCPClient({ url: 'https://your-mcp-server.com' })

// After — one line changes
const client = new MCPClient({ url: 'http://127.0.0.1:4444' })

What The Gateway Does

Request Validation

Every request is validated before reaching the upstream:

Check	What it catches
Valid JSON-RPC 2.0	Malformed requests rejected before they reach the upstream
`method` field present	Required by MCP spec
Request size ≤ 512 KB	Oversized payloads rejected before forwarding

Response Validation

Every response is validated before reaching your agent:

Check	What it catches
`result` is not null	Silent null returns
`content[]` is non-empty	Tool calls that succeeded but produced nothing
`content[]` items have `type` field	Schema drift — items normalized automatically
Response within `--timeout` ms	Hung requests — retried once automatically

Decision on every call

Decision	What it means
`allow`	Request and response valid. Passed through.
`block`	Something is wrong. Agent gets a structured error.
`retry`	Timed out. Retried once. Logged.
`rewrite`	Schema drift fixed silently.

Config file

For production or teams, create vouqis.yml in your project root:

listen: 127.0.0.1:4444
log_file: ./vouqis-audit.log

upstreams:
  - name: github-mcp
    url: https://your-mcp-server.com
    timeout_ms: 5000
    retry: 1
    policies:
      block_null_result: true
      sanitize_schema: true
      max_request_size_kb: 512

vouqis proxy   # auto-detects vouqis.yml

Structured Logs

Every decision is written to ./vouqis-audit.log in JSONL:

{"timestamp":"2026-06-03T14:23:44.000Z","upstream":"https://your-mcp-server.com","method":"tools/call","tool":"search","requestId":7,"decision":"block","latency_ms":0,"reason":"tools/call content is empty or not an array","attempt":1}

View with:

vouqis logs

VOUQIS ── audit log summary

  Total events   47
  Allowed        41
  Blocked        4
  Retried        2
  Latency P50    312ms
  Latency P95    1847ms

  Top block reasons:
    ✗ tools/call content is empty or not an array (3)
    ✗ upstream timed out after 5000ms (1)

Options: --tail 50, --summary (stats only), --file ./path/to/log

Architecture

                    Request
                       ↓

┌────────────┐
│ AI Agent   │
└─────┬──────┘
      │
      ▼
┌────────────┐
│   Vouqis   │
│  Gateway   │
└─────┬──────┘
      │
      ▼
┌────────────┐
│ MCP Server │
└────────────┘

Inside Vouqis:

Request → Validation → Forward → Response Validation → Retry Logic → Structured Logs → Return Result

Current MVP

Vouqis v0.3 focuses on five core capabilities:

Request Validation
Response Validation
Timeout Detection
Retry Logic
Structured Logs

Everything else is secondary.

Why Existing Tools Aren't Enough

Observability platforms (Langfuse, LangSmith, Braintrust, Arize) show what happened after a failure. Vouqis prevents failures before users see them.

Integration platforms (Composio, Truto, Klavis) connect tools. Vouqis validates reliability.

API gateways (Kong, Envoy, NGINX) route traffic. Vouqis understands MCP-specific failures.

Privacy

Vouqis is local-first.

What	When	Where
JSON-RPC requests	Every run	Your MCP server only
Audit log	Written locally to `./vouqis-audit.log`	Your machine only

No telemetry. No account required. Nothing leaves your machine unless you explicitly opt in.

Roadmap

Phase 1 — Reliability Gateway (now)
Request validation, response validation, timeout detection, retry logic

Phase 2 — Reliability Policies
Config-driven rules: blockNullResponse, maxLatencyMs, retryAttempts

Phase 3 — Reliability Analytics
Operational visibility for MCP reliability across your fleet

Phase 4 — Trust Layer
A reliability network powered by real-world MCP interactions

Mission

Cloudflare protects websites. Snyk protects software. Vouqis protects AI agents.

Our goal is to become the reliability layer between AI agents and the tools they depend on.

Contributing

git clone https://github.com/Sasisundar2211/Vouqis.git
cd Vouqis
npm install
npm test

Contributions are welcome. Open an issue or submit a pull request.

License

MIT License