---
name: python-debugpy-dd4600a228fc
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

```bash
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:

```py
import debugpy

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

For post-mortem:

```py
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.


---
Source attribution: openclaw
Original project: https://github.com/openclaw/openclaw/blob/cbac30f3b63366a37ed583ad2f03c0e2eef2c0c7/skills/python-debugpy/SKILL.md
License: MIT
License information: https://opensource.org/license/mit
Original upstream instructions; downloaded from Dave AI.

## Upstream license notice

MIT License

Copyright (c) 2026 OpenClaw Foundation

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.



# Dave AI resource metadata

Creator / publisher: openclaw
Original project: https://github.com/openclaw/openclaw/blob/cbac30f3b63366a37ed583ad2f03c0e2eef2c0c7/skills/python-debugpy/SKILL.md
Attribution basis: Source repository record

Fields of work: Development & Engineering
Roles: Backend Developer, DevOps / SRE, QA / Test Engineer
Specialties: Backend, Testing
Tools: Debugpy, Pdb
Country applicability: Country not specified
Classification basis: Source catalog labels
Instruction SHA-256: c76d2ba6564f3135ca1d00226ea448c8767e97b74a8774e6cf3598e640473265