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openclaw/skills/python-debugpy/SKILL.md
2026-05-17 11:56:31 +01:00

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name, description, metadata
name description metadata
python-debugpy Debug Python with pdb, breakpoint(), post-mortem inspection, and debugpy remote attach.
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.
  • Treat debugpy --pid as injection; avoid security-sensitive or production targets unless explicitly approved.
  • 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.