OmniRoute/docs/security/STEALTH_GUIDE.md

---
title: "Stealth Guide"
version: 3.8.51
lastUpdated: 2026-09-02
---

# Stealth Guide

> **Source of truth:** `open-sse/utils/tlsClient.ts`, `open-sse/services/{tlsClientBase,claudeTlsClient,perplexityTlsClient,grokTlsClient,notionTlsClient,lmarenaTlsClient,claudeCodeCCH,claudeCodeFingerprint,claudeCodeObfuscation,claudeCodeCompatible}.ts`, `open-sse/config/cliFingerprints.ts`, `src/mitm/`
> **Last updated:** 2026-09-02 — v3.8.51
> **Audience:** Engineers maintaining provider-specific stealth integrations.

OmniRoute integrates with providers whose edges actively fingerprint non-official clients (TLS JA3/JA4, header ordering, JSON body shape, integrity tokens). This page documents the stealth surfaces OmniRoute exposes and where they are implemented.

## Legal and Ethical Notice

Stealth features exist so OmniRoute can act as a compatibility layer between user-owned official accounts (Claude Code CLI, Codex, Antigravity, Cursor, etc.) and OmniRoute's unified API. They are **not** for evading fraud detection, sharing credentials, or violating provider Terms of Service. The maintainers expect operators to comply with the upstream ToS they signed when creating accounts.

---

## TLS Fingerprinting Layer

### `open-sse/utils/tlsClient.ts` — wreq-js (Chrome 124)

Persistent `wreq-js` sessions are created lazily per account scope and resolved proxy. The
process-wide `TlsClient` pools at most 128 sessions that impersonate **Chrome 124 on macOS** for
upstreams behind Cloudflare. `TlsClient.fetch()` fails closed when the native runtime is
unavailable; a caller may explicitly select a fallback outside this wrapper.

- Session profile: `browser: "chrome_124", os: "macos"`
- Proxy resolution (priority): `HTTPS_PROXY` → `HTTP_PROXY` → `ALL_PROXY` (also lower-case)
- Timeout: `TLS_CLIENT_TIMEOUT_MS` (inherits from `FETCH_TIMEOUT_MS`, default 600000)
- `wreq-js` Response is fetch-compatible (`headers`, `text()`, `json()`, `clone()`, `body`).

### Web-cookie provider transport — wreq-js 3.2.0

`open-sse/services/tlsClientBase.ts` is the shared adapter for the five specialized
web-cookie transports below. Each thin provider wrapper selects a browser/OS profile. The adapter
uses the single wreq runtime loader and transport pool in `open-sse/utils/tlsClient.ts`, keyed by
profile + OS + resolved proxy, while every request uses `cookieMode: "ephemeral"`. Accounts and
requests therefore share transport-level connections, but never a wreq session or cookie jar.

| Provider   | Profile       | Emulated OS | Stream EOF policy                |
| ---------- | ------------- | ----------- | -------------------------------- |
| Claude     | `chrome_146`  | Linux       | include `[DONE]`                 |
| Perplexity | `firefox_148` | macOS       | include `event: end_of_stream`   |
| Grok       | `chrome_146`  | Linux       | exclude `[DONE]`                 |
| Notion     | `chrome_146`  | Windows     | include `[DONE]`                 |
| LMArena    | `chrome_146`  | Windows     | no sentinel; close on native EOF |

- Streaming consumes the native response `ReadableStream` directly; no temp file or sidecar is
  created.
- Up to 256 initial bytes are inspected before exposing a stream. SSE providers buffer non-SSE
  errors; Grok/LMArena map Cloudflare challenges to `403` and HTML interstitials to `502`.
- The native request timeout remains wrapped by an absolute JS hard deadline. A hang invalidates
  and closes only the affected profile/OS/proxy transport before the next request recreates it.
- Proxy resolution priority is per-call `proxyUrl` → request-scoped account/dashboard context →
  `HTTPS_PROXY`/`HTTP_PROXY`/`ALL_PROXY` (including lowercase variants). Resolution errors fail
  closed instead of leaking a direct connection. LMArena deliberately resolves against `arena.ai`.
- `byteResponse` returns a content-typed `data:` URL without UTF-8 corruption.
- Errors are `TlsClientUnavailableError` (package/addon unavailable), `TlsClientHangError`
  (deadline exceeded), and `WreqTransportCapacityError` (the shared session-capacity error code)
  when all 128 bounded profile/OS/proxy slots are active or closing.

The generic `TlsClient` session above remains specialized for persistent browser-backed cookie
state. Both paths reuse one cached wreq module loader and process lifecycle hook; their pools remain
separate because their cookie lifetimes are intentionally different.

The profiles are supported by the pinned package, but real WAF acceptance can change independently
of local contract tests. Validate fingerprint changes against an explicitly authorized live account
before claiming parity with an upstream browser.

---

## Claude Code Stealth Bundle

When `cliCompatMode` is on, OmniRoute reshapes outgoing Claude requests so they are indistinguishable from `claude-cli` traffic. Three modules collaborate:

### `claudeCodeFingerprint.ts`

Computes the 3-char `cc_version` fingerprint embedded in the billing header:

```
SHA256(SALT + msg[4] + msg[7] + msg[20] + version)[:3]
```

- `FINGERPRINT_SALT = "59cf53e54c78"` (hardcoded; matches official client)
- Inputs: chars at index 4, 7, 20 of the first user message text + version string
- Output: 3-char hex prefix

### `claudeCodeCCH.ts` (Client Content Hash)

Server-side integrity check the official Claude Code CLI computes via Bun/Zig. OmniRoute reimplements with `xxhash-wasm`:

1. Serialize body with `cch=00000;` placeholder
2. `xxhash64(bytes, seed) & 0xFFFFF`
3. Zero-padded 5-char lowercase hex
4. Replace `cch=00000;` with the computed token

Constants:

- Seed: `0x6e52736ac806831e`
- Pattern: `/\bcch=([0-9a-f]{5});/`

### `claudeCodeObfuscation.ts`

Inserts a Unicode **zero-width joiner** (`U+200D`) after the first character of "sensitive" client names so upstream filters cannot grep them. Default word list:

```
opencode, open-code, cline, roo-cline, roo_cline, cursor, windsurf,
aider, continue.dev, copilot, avante, codecompanion
```

Applied to: `system` blocks, all `messages[].content`, and `tools[].description` / `tools[].function.description`. Operator-overridable via `setSensitiveWords()`.

### `claudeCodeCompatible.ts` — `anthropic-compatible-cc-*` providers

For third-party Anthropic relays that only accept "real Claude Code" traffic:

- `CLAUDE_CODE_COMPATIBLE_USER_AGENT = "claude-cli/2.1.258 (external, sdk-cli)"`
- `CLAUDE_CODE_COMPATIBLE_STAINLESS_PACKAGE_VERSION = "0.112.1"`
- `CLAUDE_CODE_COMPATIBLE_STAINLESS_RUNTIME_VERSION = "v26.3.0"`
- `anthropic-beta = "claude-code-20250219,interleaved-thinking-2025-05-14,effort-2025-11-24"` by default
- The per-connection "Enable redact-thinking beta" toggle adds `redact-thinking-2026-02-12` when a CC Compatible upstream specifically requires redacted thinking streams
- The per-connection "Enable summarized thinking display" toggle stores `providerSpecificData.requestDefaults.summarizeThinking` and adds `display: "summarized"` to CC Compatible thinking requests that did not already set a display mode
- `CONTEXT_1M_BETA_HEADER = "context-1m-2025-08-07"` (Opus/Sonnet 4.x family)
- Default path: `/v1/messages?beta=true`

Sister modules in the same bundle:

- `claudeCodeConstraints.ts` — temperature + cache-control rules
- `claudeCodeToolRemapper.ts` — tool-name remapping
- `claudeCodeExtraRemap.ts` — extra payload normalization

---

## Antigravity Stealth

Antigravity requests preserve caller text byte-for-byte. OmniRoute does not insert zero-width characters into prompts or rename/inject tools to imitate an IDE client.

### `antigravityHeaderScrub.ts`

Strips Stainless SDK markers (`x-stainless-lang`, `x-stainless-package-version`, `x-stainless-os`, `x-stainless-arch`, `x-stainless-runtime`, `x-stainless-runtime-version`, `x-stainless-timeout`, `x-stainless-retry-count`, `x-stainless-helper-method`) before forwarding.

### ⚠️ Risk: `ANTIGRAVITY_CREDITS=always` (account-ban hot spot)

`ANTIGRAVITY_CREDITS=always` (consumed by `open-sse/executors/antigravity.ts`) routes **every** request through Antigravity AI Credit Overages (paid Google credits) instead of letting Google's free-tier quota gate things. This is documented as a feature, but it is **the single most common ToS-violation report we see** — multiple Google Ultra accounts have been banned with `403 / "service disabled for ToS violation" / insufficient_quota` after running for a few hours with `=always`.

The upstream enforcement is on **Google's side**, not anything OmniRoute can prevent. The env var name and the existing docs make it sound like a safe knob to flip; it isn't.

**Why this draws abuse detection more aggressively than free-tier-only usage:**

- Sustained automated spend on a single Google account flags differently than free-tier hits-quota-and-stops.
- Credit overages have no rate ceiling, so a misconfigured client can burn through several hundred USD in minutes and look like API-key resale or bot traffic.
- Multiple OmniRoute users hitting overage credits in parallel from the same external IP compounds the signal.

**Recommended posture:**

1. Keep the default `ANTIGRAVITY_CREDITS=off` unless the operator explicitly accepts paid-credit and account-enforcement risk. `retry` sends the normal request first and injects credits at most once after an eligible quota 429; `always` injects credits on the first request.
2. **Spread load across providers via Auto-Combo** (`model: "auto"` or `kr/glm/etc`-combo) instead of saturating a single Antigravity account.
3. **Set per-connection RPM limits** in the Antigravity provider's edit page (Dashboard → Providers → Antigravity → connection → rate limit). 30–60 RPM is a defensible upper bound for sustained use.
4. **Use stable, operator-controlled upstream networking** and avoid sharing one account across unrelated users or workloads.
5. **If banned**: appeal via `support.google.com` → "Restore Workspace/Account access" with the exact `quota_exceeded` / `service disabled` response body Google sent. Restoration is not guaranteed.

The environment reference documents the account and spend implications of each credits mode.

Touch points:

- `open-sse/executors/antigravity.ts` — reads `process.env.ANTIGRAVITY_CREDITS`
- `src/lib/oauth/providers/antigravity.ts` — credential plumbing
- Original incident report: Discussion [#1183](https://github.com/diegosouzapw/OmniRoute/discussions/1183)

---

## CLI Fingerprint Registry — `open-sse/config/cliFingerprints.ts`

Per-provider table that pins **exact** header ordering and JSON body field ordering captured from mitmproxy traces of the official CLIs. Currently registered: `codex`, `claude`, plus runtime-derived profiles in `providerHeaderProfiles.ts` for `antigravity` and `github`.

```ts
interface CliFingerprint {
  headerOrder: string[]; // case-sensitive
  bodyFieldOrder: string[]; // top-level JSON keys
  userAgent?: string | (() => string);
  extraHeaders?: Record<string, string>;
}
```

Toggle per provider via env (see below). When disabled, headers/body keys appear in whatever order Node/JSON gave them — easy to fingerprint.

---

## MITM Proxy (Antigravity, Linux/macOS/Windows)

For CLIs whose binaries cannot be redirected via `OPENAI_BASE_URL`, OmniRoute runs a local TLS-terminating proxy. Endpoints live under `src/app/api/cli-tools/antigravity-mitm/`.

| Method | Endpoint                                | Purpose                                          |
| ------ | --------------------------------------- | ------------------------------------------------ |
| GET    | `/api/cli-tools/antigravity-mitm`       | Status — running, pid, dnsConfigured, certExists |
| POST   | `/api/cli-tools/antigravity-mitm`       | Start MITM (requires `apiKey` + `sudoPassword`)  |
| DELETE | `/api/cli-tools/antigravity-mitm`       | Stop MITM                                        |
| GET    | `/api/cli-tools/antigravity-mitm/alias` | List model aliases                               |
| PUT    | `/api/cli-tools/antigravity-mitm/alias` | Save model aliases for a tool                    |

Target intercepted host: **`daily-cloudcode-pa.googleapis.com`** (Antigravity's upstream).

### Start sequence (`src/mitm/manager.ts::startMitm`)

1. Generate self-signed cert via `selfsigned` (RSA-2048, SHA-256, 1y) — `cert/generate.ts`
2. Install cert to system trust store — `cert/install.ts`
3. Add hosts entry `127.0.0.1 daily-cloudcode-pa.googleapis.com` — `dns/dnsConfig.ts`
4. Spawn `src/mitm/server.cjs` with `ROUTER_API_KEY` + `MITM_LOCAL_PORT` (default `443`)
5. Persist PID to `<DATA_DIR>/mitm/.mitm.pid`

### Linux dynamic trust-store detection — `cert/install.ts`

`getLinuxCertConfig()` walks a priority list and picks the first existing directory:

| Distro family            | Directory                                   | Update command           |
| ------------------------ | ------------------------------------------- | ------------------------ |
| Debian / Ubuntu          | `/usr/local/share/ca-certificates`          | `update-ca-certificates` |
| Arch / CachyOS / Manjaro | `/etc/ca-certificates/trust-source/anchors` | `update-ca-trust`        |
| Fedora / RHEL / CentOS   | `/etc/pki/ca-trust/source/anchors`          | `update-ca-trust`        |
| openSUSE                 | `/etc/pki/trust/anchors`                    | `update-ca-certificates` |

Cert filename: `omniroute-mitm.crt`. Fingerprint match via `getCertFingerprint()` (SHA-1 of DER).

Additionally, `updateNssDatabases()` installs into per-user NSS DBs when `certutil` is available: `~/.pki/nssdb`, `~/snap/chromium/.../nssdb`, all Firefox profiles (including snap), under the nickname **`OmniRoute MITM Root CA`**.

### macOS / Windows

- **macOS:** `security add-trusted-cert -d -r trustRoot -k /Library/Keychains/System.keychain`
- **Windows:** elevated PowerShell → `certutil -addstore Root`

### Auth

All MITM endpoints require management auth (`requireCliToolsAuth`). The sudo password is cached in module scope (never `globalThis`) and cleared on `stopMitm()`.

---

## User-Agent Overrides — env vars (`.env.example` section 12)

| Variable                 | Default                                                         |
| ------------------------ | --------------------------------------------------------------- |
| `CLAUDE_USER_AGENT`      | `claude-cli/2.1.258 (external, cli)`                            |
| `CODEX_USER_AGENT`       | `codex-cli/0.149.0 (Windows 10.0.26200; x64)`                   |
| `GITHUB_USER_AGENT`      | `GitHubCopilotChat/0.54.0`                                      |
| `ANTIGRAVITY_USER_AGENT` | `antigravity/2.0.1 linux/arm64 google-api-nodejs-client/10.3.0` |
| `KIRO_USER_AGENT`        | `AWS-SDK-JS/3.0.0 kiro-ide/1.0.0`                               |
| `QODER_USER_AGENT`       | `Qoder-Cli`                                                     |
| `CURSOR_USER_AGENT`      | `Cursor/3.4`                                                    |

Consumed by `open-sse/executors/base.ts::buildHeaders()` via dynamic lookup. **Bump these when providers release new CLI versions** — stale UA strings start getting rejected as outdated clients.

## CLI Compatibility Mode Toggles (`.env.example` section 13)

| Variable                   | Effect                          |
| -------------------------- | ------------------------------- |
| `CLI_COMPAT_CODEX=1`       | Codex fingerprint               |
| `CLI_COMPAT_CLAUDE=1`      | claude-cli fingerprint          |
| `CLI_COMPAT_GITHUB=1`      | GitHub Copilot Chat fingerprint |
| `CLI_COMPAT_ANTIGRAVITY=1` | Antigravity fingerprint         |
| `CLI_COMPAT_KIRO=1`        | Kiro                            |
| `CLI_COMPAT_CURSOR=1`      | Cursor                          |
| `CLI_COMPAT_KIMI_CODING=1` | Kimi Coding                     |
| `CLI_COMPAT_KILOCODE=1`    | KiloCode                        |
| `CLI_COMPAT_CLINE=1`       | Cline                           |
| `CLI_COMPAT_ALL=1`         | Enable all of the above         |

The provider IP is **always preserved** — the toggle only reshapes the request wire image, it does not switch IP egress.

---

## Inbound Header Sanitization

OmniRoute scrubs inbound client headers before forwarding so a request that arrives from Cursor doesn't leak `User-Agent: Cursor/X.Y.Z` to a Claude upstream. See `src/shared/constants/upstreamHeaders.ts` for the denylist, kept in lockstep with the Zod schemas and unit tests.

---

## Updating Fingerprints When a Provider Rotates

1. Capture official CLI traffic with `mitmproxy` (TLS interception + dump)
2. Extract JA3/JA4 and the literal header order
3. Update the relevant `CLI_FINGERPRINTS[...]` entry
4. Bump matching `*_USER_AGENT` default in `.env.example`
5. If the TLS handshake itself changed, update the relevant provider wrapper or the wreq-js `browser:` option
6. Run the provider-specific TLS tests and a manual canary against the live provider
7. Ship in a patch release; document in `CHANGELOG.md`

---

## Tests

- `open-sse/services/__tests__/claudeTlsClient.test.ts` — shared TLS wrapper behavior
- `tests/unit/anthropic-cache-fingerprint.test.ts` — fingerprint determinism
- `tests/unit/chatgpt-web-source-retirement.test.ts` — common ChatGPT Web stealth source remains absent while Codex Web stays present

---

## See Also

- [RESILIENCE_GUIDE.md](../architecture/RESILIENCE_GUIDE.md) — what happens when a stealth path gets a `403`
- [TROUBLESHOOTING.md](../guides/TROUBLESHOOTING.md)
- [ENVIRONMENT.md](../reference/ENVIRONMENT.md) — full env reference
- [CLI-TOOLS.md](../reference/CLI-TOOLS.md) — operator view of the MITM workflow