---
title: Configuration
description: Configure @extentos/mcp-server — environment variables, the ~/.extentos state files (install id, auth, consent), and the default vendor.
type: reference
platform: mcp
related:
  - /docs/mcp-server
  - /docs/mcp-server/auth
  - /docs/mcp-server/tools/generation
  - /docs/mcp-server/install
---

The MCP server needs **no configuration to run** — `npx -y @extentos/mcp-server@latest` works out of the box, anonymously, with sensible defaults. The settings below are escape hatches: override the backend for local Extentos development, relocate the state directory, opt out of telemetry, suppress browser auto-open, or feed the `setup` diagnostic your GitHub Packages token.

> **This page is about the MCP-server shell**, not the library. The Kotlin/Swift SDK has its own separate config surface — `ExtentosConfig` (`debug`, `telemetryConsent`, …) is set in the host app's bootstrap, not via these environment variables. See the [SDK docs](/docs/sdk/android) for that surface.

## Environment variables

All settings are environment variables; there is no config file you author by hand. Every variable is optional.

| Variable | Default | What it does |
|---|---|---|
| `EXTENTOS_BACKEND_URL` | Production backend (`api.extentos.com`) | Override the backend base URL the server talks to. Used when developing Extentos itself against a local backend. Read by `tools/util/backendClient.ts`. |
| `EXTENTOS_CONFIG_DIR` | `~/.extentos` | Relocate the state directory (install id, auth token, consent). Useful for sandboxes, CI, or devcontainers that can't write to the home directory. |
| `EXTENTOS_TELEMETRY` | unset | Set to `0` to decline anonymous telemetry for the shell without running the CLI consent command. Takes precedence over the on-disk consent file (the escape hatch for environments that can't persist consent). |
| `EXTENTOS_NO_AUTO_OPEN` | unset | Set to `1` to suppress the browser auto-open on simulator-session creation (headless / SSH / sandboxed environments). The session URL is still returned in the tool response for the developer to open manually — nothing is lost. |
| `GITHUB_TOKEN` | unset | Read by `extentos-mcp setup` to validate the Meta DAT GitHub-Packages PAT, needed only for camera/display apps that depend on `com.extentos:glasses-meta` (those `mwdat-*` artifacts live on GitHub Packages and need a token with `read:packages` scope). This is a **setup-diagnostic input**, not a runtime dial — the running MCP server never reads it; only the `setup` subcommand does. |
| `GITHUB_USERNAME` | `token` | Optional companion to `GITHUB_TOKEN` for the same `setup` diagnostic — the Basic-auth username for the GitHub Packages Maven endpoint. Defaults to the literal `token` (GitHub accepts any username when the password is a valid PAT). |

`EXTENTOS_TELEMETRY` and `EXTENTOS_CONFIG_DIR` are the only ones that change persistent state; the rest are per-process.

## State files

The server keeps a small amount of state under `~/.extentos` (override the directory with `EXTENTOS_CONFIG_DIR`):

| File | Holds |
|---|---|
| `install.json` | The stable anonymous `installId` (`inst_…`) tagged onto every backend request and telemetry event, plus first-run metadata. Not a secret — it's the same value sent to `api.extentos.com` on every tool call. |
| `auth.json` | The bearer token written after account linking. Present only once linked; cleared by `extentos-mcp logout`. |
| `consent` | One of `accepted` / `declined` — the telemetry consent decision. Absent until you run `accept-privacy` / `decline-privacy`. `EXTENTOS_TELEMETRY=0` overrides it. |

The auth and consent lifecycle is documented in full on the [auth page](/docs/mcp-server/auth). You never edit these files by hand — the CLI subcommands (`login`, `logout`, `accept-privacy`, `decline-privacy`, `whoami`, `status`) manage them.

## Default vendor

The only glasses vendor in the current MVP is `meta_rayban` — every tool that takes a `glasses` argument requires it. There is no vendor-selection setting; the value is passed per tool call (e.g. `getPlatformInfo({ glasses: "meta_rayban" })`, `generateConnectionModule({ glasses: "meta_rayban", … })`). Additional vendors will surface as new accepted values on those tools when they ship.

## Related

- **[Auth](/docs/mcp-server/auth)** — the device-code flow, `auth.json`, and the CLI auth commands that manage the state files above
- **[MCP server overview](/docs/mcp-server)** — the tool catalog, the canonical agent flow, and the CLI subcommands
- **[Setup and Generation tools](/docs/mcp-server/tools/generation)** — `generateConnectionModule`, which references the `GITHUB_TOKEN` setup diagnostic for the Meta DAT repo
- **[Install](/docs/mcp-server/install)** — per-host install commands and JSON snippets