> ## Documentation Index
> Fetch the complete documentation index at: https://docs.yellow.pro/llms.txt
> Use this file to discover all available pages before exploring further.

# Configuration

> Environment variables that control the Yellow.pro MCP server — credentials, environment selection, trading, module filtering, and rate limiting.

The server is configured entirely through environment variables, set in your MCP client's config or your shell environment.

## Environment variables

| Variable                    | Required      | Default                          | Description                                                                    |
| --------------------------- | ------------- | -------------------------------- | ------------------------------------------------------------------------------ |
| `YELLOW_PRO_BASE_URL`       | No            | selected by `YELLOW_PRO_SANDBOX` | Explicit REST base URL override                                                |
| `YELLOW_PRO_SANDBOX`        | No            | `false`                          | Case-insensitive `true` uses staging; any other value uses production          |
| `YELLOW_PRO_API_KEY`        | Private tools | —                                | API key                                                                        |
| `YELLOW_PRO_API_SECRET`     | Private tools | —                                | API secret (HMAC-SHA256)                                                       |
| `YELLOW_PRO_APP_SESSION_ID` | Private tools | —                                | App session id, included in the request signature                              |
| `YELLOW_PRO_ENABLE_TRADING` | No            | off                              | Case-insensitive `true` enables trading tools; any other value leaves them off |
| `YELLOW_PRO_MODULES`        | No            | all                              | Comma list of `market`, `account`, `trading`                                   |
| `YELLOW_PRO_RATE_LIMIT_MS`  | No            | `100`                            | Minimum gap between requests, in milliseconds                                  |

<Info>
  Both boolean flags are compared case-insensitively, so `true`, `True`, and `TRUE` all work. Anything else — including `1` and `yes` — counts as off.
</Info>

## Environments

By default the server talks to production at `https://trade.api.yellow.pro`. Setting `YELLOW_PRO_SANDBOX=true` switches to staging at `https://api.staging.yellow.pro.neodax.app`. An explicit `YELLOW_PRO_BASE_URL` takes precedence over sandbox mode.

<Warning>
  Credentials are environment-specific: keys created for staging do not work on production, and vice versa. Note that there is currently no documented way to obtain staging credentials — see [Getting your credentials](/mcp/credentials#environments).
</Warning>

## Credentials

Market data tools work without any credentials. Everything else requires all three of `YELLOW_PRO_API_KEY`, `YELLOW_PRO_API_SECRET`, and `YELLOW_PRO_APP_SESSION_ID`. See [Getting your credentials](/mcp/credentials).

One exception: `get_fee_schedule` lives in the `account` module but calls a public endpoint and needs no credentials.

## Enabling trading

Trading tools are **not registered** unless `YELLOW_PRO_ENABLE_TRADING` is set to `true`. This is a deliberate safety default: with the flag off, an agent has no order-placing tool to call at all.

<Warning>
  Do not work around a disabled-trading state by calling the REST API directly. The opt-in flag exists so that order placement is a conscious choice. Read [Risk and safety](/mcp/risk-and-safety) first.
</Warning>

## Module filtering

`YELLOW_PRO_MODULES` accepts exactly three tokens, comma-separated:

```bash theme={null}
YELLOW_PRO_MODULES=market,account
```

| Token     | Loads                                                         |
| --------- | ------------------------------------------------------------- |
| `market`  | Public market-data tools                                      |
| `account` | Account state, history, fee tiers                             |
| `trading` | Order placement, cancellation, position management, transfers |

Omit the variable to load everything. Listing `trading` still has no effect unless `YELLOW_PRO_ENABLE_TRADING=true`.

<Warning>
  **Unrecognised module names are silently dropped** — no warning, no error. A plural typo such as `markets,account` yields account-only tools and looks like a broken install. If tools are missing, check this value character by character.
</Warning>

## Rate limiting

`YELLOW_PRO_RATE_LIMIT_MS` sets the minimum gap between outbound requests, defaulting to 100 ms.

<Warning>
  Lowering this does not make the client more resilient. A `429` from the exchange is thrown immediately with no retry and no backoff, so an aggressive value converts throttling into hard failures.
</Warning>