Sondr A flight recorder and debugging partner for your Linux terminal.

Sondr remembers what you've tried, suggests the next safe command to run, notices when you're going in circles, and teaches you the why. It runs entirely on your machine.

Install See it in action

Free · Linux · by Aspida Security

What it does

Never lose the thread.

Sondr keeps a case file of what you ran, what failed, and what you ruled out. Close the terminal and pick up tomorrow where you left off.

Know the next move.

It suggests the next read-only command that will actually tell you something, and explains why.

Learn as you go.

Every suggestion links to a short explanation of the Linux concept behind it. A built-in tour, and sondr learn keeps track of the ideas you've met.

See it in action

From Sondr's built-in tour

$ sondr open "health check failing"
opened case #1 — health check failing
pulled in 2 observations from the last 10m
$ sondr run -- ./check-health.sh
…
Traceback (most recent call last):
  File "orbit_api/settings.py", line 14, in load_settings
    url = os.environ['DATABASE_URL']
KeyError: 'DATABASE_URL'
orbit-api-1  exited with code 1
$ sondr next
Known  ctr.exited orbit-api=1
       env.missing_var DATABASE_URL
       log.exception KeyError=orbit_api/settings.py:14
Hypotheses
h1 open       The application started and then died on an unhandled error.
h2 open       The kernel killed the process for exceeding the container's memory limit.
h3 open       The container could not start its command: wrong ENTRYPOINT or CMD, …
h4 supported  The application started but refused to run without an environment
              variable, config file or secret that is not present in the container.
Next
1. [observe] docker inspect orbit-api --format 'OOMKilled={{.State.OOMKilled}} ExitCode={{.State.ExitCode}} Error={{.State.Error}}'
   Gives the exit code, OOMKilled flag and the runtime's start error.
   …

Real output from a practice run, trimmed (… marks what was cut). orbit-api is a practice script that pretends to be a container. Sondr suggests. You decide. It never runs a suggestion for you.

Install

Download the installer

curl -fsSLO https://github.com/aspida-security/sondr-releases/releases/latest/download/install.sh

Optional: read it first (press q to quit)
```
less install.sh
```
Run it
```
sh install.sh
```
Then start Sondr
```
sondr
```

The installer checks the download's SHA-256 checksum and stops if it doesn't match. On Ubuntu, Debian and Kali it installs a .deb package (it will ask for your password). Elsewhere it installs to ~/.local/bin. The first time you run sondr, a short setup walks you through everything. Type sondr tour for a 5-minute guided practice run.

Prefer to download manually? All packages and checksums are on the releases page.

Supported: Ubuntu 22.04, 24.04 and 26.04, Debian 12, Kali Linux, Fedora (tarball). x86_64 and arm64 builds. Windows users: works inside WSL2 (Ubuntu).

Works with AI coding assistants

Sondr gives Claude Code and OpenAI Codex a shared case file of what's been tried, and warns them when they're stuck in a loop. Connect with sondr agent install claude or sondr agent install codex. It shows you every change first.

Privacy

Everything stays on your computer. No accounts, no cloud, no telemetry.
Sondr never runs the commands it suggests.
Passwords, tokens and keys are masked before anything is saved.
AI assistants only see what you choose to share.

Common questions

Is it free?

Yes. Sondr is free for personal and commercial use under the Elastic License 2.0. It is not open source.

Does it slow down my terminal?

No. It records a tiny note per command in the background.

Does it need an AI model?

No. A local model (Ollama) is optional.

How do I turn it off or uninstall it?

sondr off pauses recording in that terminal. To uninstall, run sondr uninstall, then sudo apt remove sondr.

What does setup change on my computer?

Setup shows each change and asks before making it. To record your commands it adds one marked block to your shell's startup file (for bash, ~/.bashrc), between # >>> sondr >>> and # <<< sondr <<<. The block checks that Sondr is installed first, so your terminal keeps working even if Sondr is removed.

If it finds a coding agent such as Claude Code, it shows you each change first (a diff for files, the exact command for the rest), saves a backup of the settings file it edits, and only then applies it. You can run sondr setup again at any time.

Where do I report a problem?

Run sondr feedback, or email sondrsupport@vappler.com.

Support and feedback

Found a bug or have an idea? Run sondr feedback, or open an issue.

Email: sondrsupport@vappler.com