How to Disable Telemetry in Feynman: Environment Variable Configuration Guide

Set the environment variable FEYNMAN_TELEMETRY=off or DO_NOT_TRACK=1 before running Feynman to completely disable all PostHog telemetry collection and bypass the analytics stack.

Feynman integrates telemetry via PostHog to collect usage analytics, but the open-source project provides straightforward opt-out mechanisms through environment variables. Whether you need to disable tracking for privacy compliance, corporate security policies, or personal preference, you can disable telemetry without modifying any source code by leveraging the configuration resolver in src/telemetry/posthog.ts.

How Telemetry Control Works in Feynman

The telemetry system evaluates opt-out preferences during initialization through the resolvePostHogTelemetryConfig function in src/telemetry/posthog.ts. This function checks the runtime environment for specific variables; if either FEYNMAN_TELEMETRY=off or DO_NOT_TRACK=1 is present, the function returns undefined, which causes the rest of the telemetry stack—including the PostHog client, OTLP transport, and circuit-breaker logic—to be bypassed entirely.

When telemetry is disabled, subsequent calls to getPostHogOtelEnv produce a clean environment without any PostHog-related keys, ensuring no analytics data reaches external servers.

Methods to Disable Feynman Telemetry

Using Environment Variables (CLI)

The simplest method to disable telemetry is setting one of two supported environment variables before invoking the Feynman CLI. This approach requires no code changes and works for both temporary and session-wide disabling.

Disable telemetry for a single command:

# Option 1: Use the Feynman-specific variable

FEYNMAN_TELEMETRY=off feynman rank "some topic"

# Option 2: Use the standard Do Not Track convention

DO_NOT_TRACK=1 feynman rank "some topic"

Disable telemetry for an entire shell session:

export FEYNMAN_TELEMETRY=off

# or

export DO_NOT_TRACK=1

# All subsequent Feynman commands run without telemetry

feynman rank "another topic"

Permanent Configuration in Shell Profiles

To permanently disable telemetry across all sessions, add the export statement to your shell's configuration file. This ensures the opt-out persists across terminal restarts.

For Bash users:

echo 'export FEYNMAN_TELEMETRY=off' >> ~/.bashrc

For Zsh users:

echo 'export DO_NOT_TRACK=1' >> ~/.zshrc

Reload your profile with source ~/.bashrc or source ~/.zshrc to apply changes immediately.

Programmatic Disabling in Node.js

When spawning Feynman as a child process or using it programmatically, pass the environment variable explicitly in the env option:

const { spawn } = require('child_process');

const child = spawn('feynman', ['rank', 'topic'], {
  env: { ...process.env, FEYNMAN_TELEMETRY: 'off' }
});

child.stdout.pipe(process.stdout);
child.stderr.pipe(process.stderr);

If importing Feynman's API directly as a library, you can disable telemetry by passing an explicit environment configuration to initializePostHogTelemetry:

import { initializePostHogTelemetry } from './src/telemetry/posthog.js';

initializePostHogTelemetry({
  home: '/tmp/feynman',
  appVersion: '0.3.4',
  serviceName: 'my-tool',
  env: { FEYNMAN_TELEMETRY: 'off' }  // Opt-out here
});

Verification Through the Test Suite

The opt-out behavior is rigorously validated in tests/telemetry.test.ts. The test case "resolvePostHogTelemetryConfig respects telemetry opt out" asserts that passing { FEYNMAN_TELEMETRY: "off" } or { DO_NOT_TRACK: "1" } causes the configuration resolver to return undefined, preventing telemetry initialization.

Additionally, the test "getPostHogOtelEnv clears inherited telemetry env when telemetry is disabled" confirms that when telemetry is disabled, getPostHogOtelEnv produces a sanitized environment without PostHog-related keys, as verified around lines 99-108 of the test file.

Key Source Files

The following files in the advaitpaliwal/feynman repository implement and verify the telemetry control logic:

• src/telemetry/posthog.ts – Contains resolvePostHogTelemetryConfig and initializePostHogTelemetry, which evaluate environment variables to determine telemetry activation.
• src/pi/runtime.ts – Entry point where getPostHogOtelEnv applies the telemetry configuration to the Pi runtime environment.
• tests/telemetry.test.ts – Test suite confirming that both FEYNMAN_TELEMETRY=off and DO_NOT_TRACK=1 properly disable the telemetry stack.

Summary

• Set FEYNMAN_TELEMETRY=off or DO_NOT_TRACK=1 to disable telemetry without code changes.
• The resolvePostHogTelemetryConfig function in src/telemetry/posthog.ts evaluates these variables during initialization.
• Permanent opt-out is achieved by adding the export to your shell profile (~/.bashrc or ~/.zshrc).
• Programmatic usage requires passing the environment variable in the env configuration object.
• The test suite in tests/telemetry.test.ts validates that telemetry is fully bypassed when these variables are set.

Frequently Asked Questions

What environment variables disable Feynman telemetry?

Feynman checks two environment variables: FEYNMAN_TELEMETRY=off and DO_NOT_TRACK=1. Either variable will cause the resolvePostHogTelemetryConfig function to return undefined, completely disabling the PostHog telemetry integration.

Does disabling telemetry affect Feynman's functionality?

No. Disabling telemetry only prevents analytics data collection and transmission. All core ranking, search, and language processing features continue to function normally; the application simply bypasses the PostHog client initialization and OTLP transport layers.

How can I verify that telemetry is actually disabled?

You can verify the configuration by checking that resolvePostHogTelemetryConfig returns undefined when your environment variables are set. In the Feynman test suite, the file tests/telemetry.test.ts demonstrates this verification approach, confirming that the getPostHogOtelEnv function returns an environment object without PostHog-related keys when telemetry is disabled.

Can I disable telemetry programmatically when using Feynman as a library?

Yes. When calling initializePostHogTelemetry programmatically, pass an env object containing FEYNMAN_TELEMETRY: 'off'. When spawning Feynman as a child process, include the environment variable in the env option of child_process.spawn. Both methods prevent the telemetry stack from initializing without requiring global environment changes.

{
  "mcpServers": {
    "instagit": {
      "command": "npx",
      "args": ["-y", "instagit@latest"]
    }
  }
}