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

# tally/prefer-telemetry-opt-out

> Stages using telemetry-enabled tools should set the vendor-documented opt-out environment variables.

Stages using telemetry-enabled tools should set the vendor-documented opt-out environment variables.

| Property | Value                      |
| -------- | -------------------------- |
| Severity | Info                       |
| Category | Privacy                    |
| Default  | Enabled                    |
| Auto-fix | Yes (`--fix --fix-unsafe`) |

## Description

Detects build stages that clearly use tools with an official telemetry opt-out and suggests adding a
grouped telemetry block near the top of the stage.

The rule is intentionally conservative:

* It emits at most **one violation per stage**
* It only targets tools with a vendor-documented environment-variable opt-out
* It suppresses child stages when the required opt-outs are already inherited from a parent stage
* It only inserts the opt-outs that are still missing for that specific stage
* The fix groups the missing opt-outs into one `ENV` instruction with a short tally comment

## Supported tools

The v1 rule targets these opt-outs:

* `DO_NOT_TRACK=1` for Bun
* `AZURE_CORE_COLLECT_TELEMETRY=0` for Azure CLI
* `WRANGLER_SEND_METRICS=false` for Wrangler
* `HF_HUB_DISABLE_TELEMETRY=1` for the Hugging Face Python ecosystem
* `YARN_ENABLE_TELEMETRY=0` for Yarn Berry
* `NEXT_TELEMETRY_DISABLED=1` for Next.js
* `NUXT_TELEMETRY_DISABLED=1` for Nuxt
* `GATSBY_TELEMETRY_DISABLED=1` for Gatsby
* `ASTRO_TELEMETRY_DISABLED=1` for Astro
* `TURBO_TELEMETRY_DISABLED=1` for Turborepo
* `DOTNET_CLI_TELEMETRY_OPTOUT=1` for .NET CLI / SDK
* `POWERSHELL_TELEMETRY_OPTOUT=1` for PowerShell
* `VCPKG_DISABLE_METRICS=1` for vcpkg
* `HOMEBREW_NO_ANALYTICS=1` for Homebrew

## Detection signals

The rule prefers strong, stage-local evidence in this order:

* direct command execution in `RUN`, `CMD`, `ENTRYPOINT`, or `SHELL`
* explicit CLI installation in the same stage
* observable manifests or config files that clearly name the tool

Examples:

* `RUN bun install`
* `RUN npx wrangler deploy`
* `RUN python -m huggingface_hub scan-cache`
* `RUN next build`
* `COPY package.json ./package.json` plus `RUN npm run build` when `package.json` declares `next`
* `COPY requirements.txt ./requirements.txt` plus `RUN pip install -r requirements.txt` when the file mentions `transformers`

Manifest-based detection depends on files being observable to the linter, which means either:

* they are created in the Dockerfile (for example via `COPY <<EOF` heredoc), or
* they come from the build context and linting runs with `--context`

## Auto-fix

The fix inserts a small telemetry block after `FROM` and any immediately following stage-local `ARG`
instructions:

### Before

```dockerfile theme={null}
FROM node:22
RUN bun install && next build
```

### After

```dockerfile theme={null}
FROM node:22
# [tally] settings to opt out from telemetry
ENV DO_NOT_TRACK=1 NEXT_TELEMETRY_DISABLED=1
RUN bun install && next build
```

## Suppression

The rule does **not** trigger when:

* the stage already sets the required opt-out to the documented value
* the stage inherits the required opt-out from a parent stage
* the stage only shows unsupported or ambiguous signals such as:
  * plain `yarn install` without Berry-specific evidence
  * generic `npm` or `pnpm` usage without a targeted tool
  * generic Python usage without Hugging Face packages
  * Node-only `@huggingface/hub` usage
  * AWS CLI usage

## Related rules

* [`tally/prefer-curl-config`](./prefer-curl-config) — stage-level environment/config insertion before tooling `RUN` steps
* [`tally/prefer-package-cache-mounts`](./prefer-package-cache-mounts) — stage-local package-manager cache improvements
* [`tally/powershell/prefer-shell-instruction`](./powershell/prefer-shell-instruction) — rewrites repeated PowerShell wrappers to a `SHELL`
  instruction