Privacy

Fernel exists to measure a footprint, not to learn about your work. It collects as little as possible and shows you exactly what it collects.

What the CLI uploads

One row per day, tool, project and model:

{ "date": "2026-11-04", "source": "claude-code", "project": "fernel",
  "model": "claude-opus-5-5", "input": 1204, "output": 38211,
  "cacheRead": 9120334, "cacheWrite": 201554, "reasoning": 4120, "requests": 212 }

It also sends your timezone (to group usage by day), the CLI version, and, once, your machine's name when you link it. Project names are folder names only, never full paths. Your home folder appears as (home). Run fernel sync --dry-run to print the exact payload.

Optional: sessions

Off unless you turn it on in Settings. Then the CLI also uploads one record per agent session: an anonymous id (a hash, not the session id), the project name, the first and last response time, active minutes, number of responses, subagents and compactions, and token counts per model. A second, separate switch also uploads Claude Code's short session title (for example "Fix auth redirect"), which is generated from your prompts. Sessions are never shown to your team. Turning either switch off deletes that data from Fernel's servers immediately, and fernel config sessions off blocks it on a machine whatever the dashboard says.

What never leaves your machine

Prompts, responses, code, file contents, file paths, commands, tool calls and session ids. The CLI reads your local logs only to count tokens.

Your controls

• fernel ignore <project> stops counting a project and deletes its data from Fernel.
• Unlink any machine from Settings, or with fernel logout.
• Export everything as CSV from Settings.
• Delete your account in Settings. That permanently deletes all your data straight away.
• fernel uninstall removes the background job and all local Fernel files.

Everything else

Your email is used only to sign you in. No ads, no tracking cookies, no selling or sharing of data. Data is stored in the EU. CLI tokens are stored only as hashes.

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