errex 0.4.0

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.

$ cat traceback.txt | errex.py

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

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

This is a Python type error...

Install

pip install errex
export ANTHROPIC_API_KEY=sk-...

Requires Python 3.9+ and an Anthropic API key.

Usage

# Interactive — paste your error, then Ctrl+D (Mac/Linux) or Ctrl+Z+Enter (Windows)
errex

# Read from a file
errex traceback.txt

# Pipe from another command
cat error.log | errex

# Watch a log file and auto-explain errors as they appear
errex --watch server.log

# Get just the fix command, no explanation
errex --fix traceback.txt

# One-paragraph summary instead of full analysis
errex --brief traceback.txt

# Hint the language when the error is ambiguous
errex --lang rust traceback.txt

# Copy the explanation to the clipboard
errex --copy traceback.txt

# Structured JSON output (error_type, root_cause, fix_steps, gotchas)
errex --json traceback.txt

# Use a different Claude model
errex --model claude-opus-4-7 traceback.txt

# View past explanations
errex --history
errex --history "KeyError"

Web UI

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

Paste your error in the browser, pick a model, hit Explain (or ⌘Enter). No extra dependencies.

Shell integration

Run errex --install-shell to add an errex-last function to your shell config. After any failed command, just run errex-last to explain why it failed.

Config file

Create ~/.errexrc to set your defaults (all fields optional):

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

CLI flags always override the config file.

Past explanations are saved to ~/.errex_history (one JSON object per line).

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