/python-debugpy

name: python-debugpy
description: Debug Python with pdb, breakpoint(), post-mortem inspection, and debugpy remote attach.
metadata: { "openclaw": { "requires": { "bins": ["python3"] } } }

Python Debugpy

Use when Python code needs interactive debugging: hidden locals, confusing state mutation, failing tests, subprocesses, long-running services, or remote/headless attach.

Pick the smallest debugger that reaches the bad frame.

Choose

• `breakpoint()`: local code, source edits ok, fastest path.
• `python3 -m pdb`: no source edit, launch from the beginning.
• `python3 -m pdb -c continue`: stop at an unhandled exception.
• `debugpy`: remote/headless process, DAP client, already-running PID, or service startup race.

Commands

python3 -m pdb path/to/script.py arg1
python3 -m pdb -c continue path/to/script.py
python3 -c "import debugpy" || python3 -m pip install debugpy
python3 -m debugpy --listen 127.0.0.1:5678 --wait-for-client path/to/script.py
python3 -m debugpy --listen 127.0.0.1:5678 --wait-for-client -m package.module
python3 -m debugpy --listen 127.0.0.1:5678 --pid <pid>

For source-edit attach:

import debugpy

debugpy.listen(("127.0.0.1", 5678))
debugpy.wait_for_client()
debugpy.breakpoint()

For post-mortem:

import pdb, sys

try:
    run()
except Exception:
    pdb.post_mortem(sys.exc_info()[2])
    raise

pdb

• Flow: `n`, `s`, `r`, `c`, `q`.
• Stack/source: `w`, `u`, `d`, `a`, `l`, `ll`.
• Values: `p expr`, `pp expr`, `display expr`.
• Breakpoints: `b file.py:42`, `b func`, `b file.py:42, condition`, `cl <num>`.
• Mutate/evaluate: `!statement`; full REPL: `interact`.

Rules

• Reproduce with the smallest command/test first.
• Disable parallel test workers for pdb; interactive stdin usually breaks inside worker pools.
• Keep `debugpy` in the active env; do not add it as a project dependency unless the project already wants it.
• Bind debug servers to `127.0.0.1`; do not expose `0.0.0.0` unless isolated or tunnelled.
• Use unique ports for parallel sessions.
• `debugpy --pid` injects into a running process; confirm the target pid before attaching.
• If PID attach fails on Linux, check ptrace/container privileges before changing the target.
• Cleanup before commit: `rg -n 'breakpoint\\(|pdb\\.set_trace|debugpy\\.' --type py`.
• Rerun the normal project test/gate without the debugger.
• `PYTHONBREAKPOINT=0` disables `breakpoint()`.
• If a process is stuck after debugger detach, confirm it is not still paused at a breakpoint.