errex 0.24.0

Paste or pipe any error message and get a plain-English explanation powered by Claude

errex — Error Explainer

Paste or pipe any error message and get a clear, plain-English explanation powered by Claude — often without touching the API at all.

$ cat traceback.txt | errex

────────────────────── errex — Error Analysis ──────────────────────

⚡ matched local pattern

**TypeError: unsupported operand type(s) for +: 'int' and 'str'**

This is a Python type error. You're trying to add an integer and a
string together, which Python doesn't allow...

Install

pip install errex
export ANTHROPIC_API_KEY=sk-ant-...

Requires Python 3.9+. An Anthropic API key is needed for full explanations; local lookup commands work without one.

Quick start

errex                        # interactive paste
errex traceback.txt          # read from a file
cat error.log | errex        # pipe from stdin
errex --watch server.log     # tail a log, auto-explain errors

How it works

errex resolves every query through a three-tier speed hierarchy, from fastest to slowest:

1. ⚡ Instant (local patterns) — 71 built-in patterns covering Python, JavaScript/Node.js, Rust, Java, Go, Docker, shell, Git, network, pip/npm. Matches happen in microseconds; no API call is made and no key is required. The response badge reads ⚡ matched local pattern.

2. 📦 Fast (response cache) — When Claude has already answered the same error, the cached response is returned instantly from ~/.errex_response_cache.json (30-day TTL). The response badge reads 📦 cached response.

3. 🤖 Full (Claude) — For anything new or complex, errex calls the Claude API and stores the result in the cache. Use --no-cache to skip tiers 1 and 2 and always call Claude directly.

Local lookup commands (no API key needed)

These commands return instant answers from built-in tables and never call Claude.

errex --explain-exit 139       # SIGSEGV — segmentation fault
errex --explain-http 429       # Too Many Requests — rate limited
errex --explain-cron "*/5 * * * *"  # "every 5 minutes"
errex --explain-env PYTHONPATH # what the variable controls
errex --list-patterns          # show all 71 built-in patterns in a table

All flags

Explaining errors

Flag	What it does
errex [FILE]	Explain an error from a file, stdin, or interactive paste
--brief	One-paragraph summary instead of full analysis
--fix	Output only the fix command, no explanation
--fix-apply	Get a fix command from Claude and run it (prompts for confirmation)
--yes / -y	Auto-confirm --fix-apply without prompting
--open-ticket	Open a Red Hat Customer Portal support case with this error
--rht-username USER	Red Hat username (or set RHT_USERNAME env var)
--rht-password PASS	Red Hat password (or set RHT_PASSWORD env var)
--rht-severity 1-4	Ticket severity: 1=Urgent 2=High 3=Normal 4=Low (default: 3)
--rht-product NAME	Red Hat product name for the ticket
--rht-version VER	Product version for the ticket
--lang LANG	Language hint when the error is ambiguous (e.g. rust, go, java)
--model MODEL	Choose which Claude model to use (default: claude-sonnet-4-6)
--json	Structured JSON output: error_type, root_cause, fix_steps, gotchas
--context FILE	Attach a source file as extra context for more targeted explanations
--top N	Limit root cause to top N most likely causes
--snippet	Strip stdlib/library frames from a traceback before explaining
--format-json	Reformat JSON error before explaining
errex A.txt B.txt	Compare two error files and find shared root causes

Code tools

Flag	What it does
--explain-code FILE	Walk through what a piece of code does in plain English
--lint FILE	Scan a code file for bugs, security issues, and anti-patterns
--test-gen FILE	Generate a test case for a code file; pipe an error to reproduce the bug
--explain-diff [FILE]	Explain a git diff — pipe git diff | errex --explain-diff or pass a .patch file
--explain-regex PATTERN	Explain what a regex matches: breakdown, examples, gotchas
--explain-sql QUERY	Explain a SQL query: clause breakdown, performance notes, gotchas
--explain-yaml FILE	Explain a YAML config (auto-detects docker-compose, k8s, GitHub Actions)
--explain-dockerfile FILE	Explain a Dockerfile layer by layer
--inline FILE LINE	Explain a specific line of code in context
--grep PATTERN FILE	Filter a log file by regex, then explain matching lines
--env	Auto-attach system info (OS, Python, shell, runtimes) as context
--run CMD	Run a shell command and auto-explain any error output
--redact	Strip API keys, tokens, and passwords from error text before sending to Claude

Local lookups

Flag	What it does
--explain-exit CODE	Explain a shell exit code (e.g. 139 → SIGSEGV / segfault)
--explain-http CODE	Explain an HTTP status code
--explain-cron EXPR	Explain a cron expression in plain English
--explain-env VAR	Explain what an environment variable controls
--list-patterns	Show all 71 built-in patterns in a table

History & search

Flag	What it does
--history [SEARCH]	View past explanations, optionally filtered by keyword
--recent [N]	Show the last N explanations (default: 5)
--since DATE	Filter --history/--recent to entries on or after YYYY-MM-DD
--similar	Find past errors in your history that match the current one
--search TERM	Full-text search across all history fields
--interactive	Browse history with a numbered picker
--dedup	Show groups of near-duplicate errors in history
--ask "question"	Ask a follow-up about the last error without re-explaining it
--retry	Re-explain the last error with different flags (e.g. --retry --model claude-opus-4-7)
--stats	Usage dashboard: total runs, models, top error types, busiest day/hour
--export FILE	Export history to a styled HTML or Markdown file (--export-format html|md)
--export-csv FILE	Export history to CSV (timestamp, model, error type, rating, name)
--save-as NAME	Tag this explanation with a name for quick retrieval
--find-name NAME	Retrieve a history entry saved with --save-as
--list-named	List all history entries saved with --save-as
--add-note TEXT	Append a note to the last history entry
--pin / --unpin	Mark the last history entry as pinned (protected from --clear-history)
--filter TYPE	Filter --history/--recent to entries matching an error type (e.g. TypeError)
--clear-history [DAYS]	Delete all history, or only entries older than N days (pinned entries kept)
--rate SCORE	Rate last explanation 1–5

Cache & performance

Flag	What it does
--no-cache	Skip the local pattern cache and response cache; always call Claude
--clear-cache	Wipe the response cache (~/.errex_response_cache.json)
--tokens	Show input/output token counts after each explanation
--perf	Show response time and tokens/second after each explanation
--timeout N	API request timeout in seconds (default: 30)

Workflow & integrations

Flag	What it does
--watch LOGFILE	Tail a log file and auto-explain new errors (deduplicates repeats)
--summarize-log FILE	Digest all distinct error types in a large log file
--bulk FILE	Explain multiple errors from a file separated by blank lines
--issues	Search GitHub Issues for bugs matching your error
--share	Post the explanation to paste.rs and print a shareable link
--copy	Copy the explanation to the clipboard
--chat	Stay in a Q&A loop after the explanation
--notify	Send a desktop notification when the explanation is ready
--webhook URL	POST explanation to a Slack, Discord, or generic webhook URL
--ci	CI mode: no-color + terse output + GitHub Actions annotations + exits 1

Output & formatting

Flag	What it does
--translate LANG	Respond in a spoken language (--translate Spanish, --translate Japanese)
--json	Structured JSON output: error_type, root_cause, fix_steps, gotchas
--terse	Single-sentence diagnosis — shorter than --brief, great for scripting
--output FILE	Save the explanation to a file alongside printing
--no-color	Plain-text output with no rich formatting (safe to pipe)
--word-wrap N	Set output console width
--copy	Copy the explanation to the clipboard
--share	Post the explanation to paste.rs and print a shareable link

System health scan

errex can scan your machine for security issues, misconfigurations, and outdated software — no API key needed for the scan itself.

errex --scan                 # run a full system scan
errex --scan --scan-network  # include network device scan
errex --scan-status          # show last scan result and health streak

Flag	What it does
--scan	Run a full system health scan (logs, configs, CVEs, malware)
--scan-schedule FREQ	Schedule automatic scans (daily, weekly, monthly)
--scan-status	Show last scan result and current health-streak days
--scan-network	Also scan local network devices
--scan-severity LEVEL	Only report findings at or above this severity (low, medium, high, critical)
--scan-fix	Auto-apply safe fixes for scan findings
--scan-no-explain	Skip Claude explanations; show findings only
--scan-quiet	Suppress all scan output (useful in scripts; check exit code)
--scan-speak	Read scan findings aloud via OS text-to-speech
--scan-malware [PATH]	Run a malware/hash scan on PATH (default: home directory)
--check-hash FILE	Check a file's SHA-256 hash against known-malware databases
--vt-api-key KEY	VirusTotal API key for extended hash lookups
--simple	Simplified, high-contrast output — fewer colours, larger text; good for accessibility
--mascot	Show Rex (errex's mascot) with a context-aware motivational line

Scan tickets

Scan findings are tracked as tickets so nothing gets lost between sessions.

Flag	What it does
--tickets	List all open scan tickets
--ticket-close ID	Mark a ticket as resolved
--ticket-snooze ID	Snooze a ticket (default: 7 days; override with --snooze-days N)
--snooze-days N	Number of days to snooze (used with --ticket-snooze)
--ticket-reopen ID	Reopen a previously closed/snoozed ticket
--ticket-note ID --note TEXT	Append a note to a ticket

Network devices

errex remembers the devices on your local network and lets you give them friendly names.

Flag	What it does
--devices	List all known network devices with their nicknames
--device-rename IP --name NICK	Set a friendly nickname for a device (e.g. --device-rename 10.0.0.5 --name "Living Room TV")

Backup & restore

Before applying any auto-fix, errex backs up the affected files so you can always roll back.

errex --backups               # see all auto-fix backups
errex --restore-backup PATH   # restore a specific backup
errex --cloud-backup          # copy backups to a detected cloud-sync folder
errex --restore-point         # create an OS restore point before a big fix

Flag	What it does
--backups	List all auto-fix backups (newest first)
--restore-backup PATH	Restore a file from its backup (PATH is the backup file path shown by --backups)
--cloud-backup	Copy the backup folder into a detected cloud-sync folder (Dropbox, Google Drive, OneDrive, iCloud)
--restore-point	Create an OS-level restore point before fixing: Time Machine snapshot (macOS), System Restore (Windows), or timeshift (Linux)

Weekly digest & notifications

Flag	What it does
--digest	Print a summary of errors and fixes from the last 7 days
--digest-since N	Override the look-back window to the last N hours
--discord-webhook URL	Post the explanation or scan summary to a Discord channel
--github-token TOKEN	GitHub token for --issues lookups and PR annotations
--github-repo OWNER/REPO	GitHub repo to open issues against

Cloud sync

Flag	What it does
--sync-url URL	Remote endpoint to sync scan summaries and ticket events
--sync-key KEY	API key for the sync endpoint (or set ERREX_SYNC_KEY env var)

PR review

errex --review-pr https://github.com/owner/repo/pull/42
errex --review-pr owner/repo#42   # shorthand

Flag	What it does
--review-pr URL	Fetch a GitHub PR diff and get a structured Claude code review (summary, issues, suggestions, verdict)

Slack notifications

Flag	What it does
--slack-webhook URL	Slack incoming webhook URL for scan summaries and ticket events (or set ERREX_SLACK_WEBHOOK)

Jira integration

errex --scan --jira-project SEC --jira-url https://myteam.atlassian.net \
      --jira-user [e-mail] --jira-token $JIRA_TOKEN

Flag	What it does
--jira-project KEY	Jira project key — creates issues for each new scan finding
--jira-url URL	Jira instance base URL
--jira-user EMAIL	Jira username / email
--jira-token TOKEN	Jira API token (prefer env var JIRA_TOKEN)

Prometheus metrics

errex --prometheus 9100   # exposes http://localhost:9100/metrics

Flag	What it does
--prometheus PORT	Start a metrics server exposing error counts, open tickets by severity, and health streak in Prometheus text format

Project config

errex --init-project          # creates .errex.yml in current directory
errex --init-project --force  # overwrite existing

Commit .errex.yml to share settings (model, scanner options, ignored findings) across your team.

Flag	What it does
--init-project	Create a .errex.yml project config in the current directory
--force	Overwrite existing file (used with --init-project)

Auto-scan daemon

errex --auto-scan 60                                    # scan every 60 minutes
errex --auto-scan 30 --slack-webhook $SLACK_URL         # alert on new findings
errex --auto-scan 60 --scan-severity medium             # medium+ only

Flag	What it does
--auto-scan MINUTES	Run scans on an interval; alert only when findings change (new or resolved)

AI fix suggestions

errex --suggest-fixes
errex --suggest-fixes --scan-severity high

Flag	What it does
--suggest-fixes	Scan the system and ask Claude for concrete shell commands to fix each finding

Pro license

errex --activate ERREX-PRO-XXXXXX-XXXXXXXX   # activate a Pro license key
errex --license                               # show current license status

Flag	What it does
--activate KEY	Activate an errex Pro license key
--license	Show current license status (free / Pro, expiry, seat)

Setup & config

Flag	What it does
--config [key=value]	View or edit ~/.errexrc — e.g. --config model=claude-opus-4-7
--profile NAME	Use a named config profile
--list-profiles	List all named profiles in ~/.errexrc
--delete-profile NAME	Delete a named profile from ~/.errexrc
--setup	First-run wizard: check API key, detect languages, write config, install shell integration
--doctor	Health check: verify API key, connectivity, config, and version
--completion bash|zsh	Print a shell completion script (source <(errex --completion zsh))
--install-shell	Add errex-last() to your shell — run it after any failed command
--web	Launch a local web UI at http://localhost:7337
--update	Check PyPI for a newer version
--version	Show the installed version

Web UI

errex --web   # opens http://localhost:7337

The web UI provides a browser-based interface with:

• Real-time token streaming — explanation text appears as Claude generates it
• History sidebar — past explanations listed on the left; click any entry to reload it
• Source badge — shows whether the result came from ⚡ a local pattern or 🤖 Claude
• Full / Brief mode tabs — toggle between detailed and summary views
• Copy button and Cmd/Ctrl+Enter keyboard shortcut

Config file

~/.errexrc sets your defaults (all fields optional):

{
  "model": "claude-opus-4-7",
  "brief": false,
  "lang": "python",
  "copy": false
}

Or manage it from the CLI:

errex --config                        # show all settings
errex --config model=claude-opus-4-7  # set a value
errex --config lang=null              # reset to default

Named profiles let you keep separate configs for different projects:

errex --profile work                  # activate the "work" profile
errex --list-profiles                 # list all profiles
errex --delete-profile work           # remove a profile

Shell integration

errex --install-shell   # adds errex-last() to ~/.zshrc or ~/.bashrc

After any failed command, run errex-last to explain why it failed.

History

Every explanation is saved to ~/.errex_history (one JSON object per line).

errex --recent              # last 5 explanations
errex --history KeyError    # search history
errex --search "import"     # full-text search across all fields
errex --interactive         # browse with a numbered picker
errex --dedup               # show groups of near-duplicate errors
errex --stats               # usage dashboard
errex --export report.html  # export to HTML
errex --rate 5              # rate the last explanation 1–5

CI/CD integration

Use --ci for pipeline-friendly output:

cat build.log | errex --ci

--ci mode enables:

• No-color, terse output safe for log capture
• GitHub Actions error annotations (::error::) printed to stdout
• Exit code 1 so the step fails visibly

Example GitHub Actions step:

- name: Explain build failure
  if: failure()
  run: cat build.log | errex --ci

Deployment

Docker (quickstart)

docker run -e ANTHROPIC_API_KEY=sk-... -p 7337:7337 ghcr.io/bsel153/errex:latest

Or with docker-compose:

export ANTHROPIC_API_KEY=sk-...
docker-compose up -d

Open http://localhost:7337 in your browser. All history, cache, and config are stored in the errex-data Docker volume.

With authentication and TLS (recommended for public-facing deployments):

# docker-compose.yml
command: ["--auth", "admin:changeme", "--tls"]

systemd (Linux server)

# 1. Create a dedicated user
sudo useradd -r -m -d /var/lib/errex errex

# 2. Install errex
sudo pip install errex

# 3. Install the service file
sudo cp deploy/errex.service /etc/systemd/system/errex.service

# 4. Set your API key
sudo systemctl edit errex
# Add under [Service]:
#   Environment=ANTHROPIC_API_KEY=sk-...

# 5. Enable and start
sudo systemctl daemon-reload
sudo systemctl enable --now errex

# 6. (Optional) Add nginx reverse proxy
sudo cp deploy/nginx.conf /etc/nginx/sites-available/errex
sudo ln -s /etc/nginx/sites-available/errex /etc/nginx/sites-enabled/
sudo certbot --nginx -d errex.yourdomain.com
sudo systemctl reload nginx

The service listens on 127.0.0.1:7337 by default and is proxied through nginx with HTTPS.

LAN / mobile access

errex --web --host 0.0.0.0 --port 7337

Access from any device on your local network at http://<your-ip>:7337.

For temporary public internet access with a shareable link and QR code:

errex --web --tunnel

What you get

For any error, errex explains:

1. What kind of error it is and which language or tool produced it
2. What it means in plain English
3. The most likely root cause, ranked by probability
4. Numbered fix steps with code snippets where helpful
5. Common gotchas — the non-obvious things that trip people up