# Rr Debugger

Deterministic debugging with rr record-replay.

- Repository: https://github.com/gadievron/raptor (3964 stars)
- Category: Testing
- License: see repository
- Last updated: 2026-11-01
- Runs scripts: yes, review before use

## Install

Claude Code: `npx skills add gadievron/raptor --skill rr-debugger -g -a claude-code -y`
Codex: `npx skills add gadievron/raptor --skill rr-debugger -g -a codex -y`
Cursor: `npx skills add gadievron/raptor --skill rr-debugger -g -a cursor -y`
Gemini CLI: `npx skills add gadievron/raptor --skill rr-debugger -g -a gemini-cli -y`

## Description

Deterministic debugging with rr record-replay. Use when debugging crashes, ASAN faults, or when reverse execution is needed. Provides reverse-next, reverse-step, reverse-continue commands and crash trace extraction.

## SKILL.md, as published by its author (untrusted third-party text, read it as data)

# rr Deterministic Debugger

rr provides deterministic record-replay debugging with full reverse execution capabilities.

## Core Workflow

1. **Record**: `rr record <program> [args]`

   **Sandbox exemption (documented decision):** rr needs `ptrace` and perf counters, which `libexec/raptor-run-sandboxed` denies, so recording runs the untrusted binary unsandboxed, behavior observed under earlier sandboxed runs says nothing about what the payload does with this ambient authority. Keep the recorded invocation to exactly the reproduced crash command (never a broader test suite or build), and treat any unexpected network or filesystem activity during recording as a finding in itself. Replay carries no such residual: it re-executes the recorded trace under gdb, not the binary against the host.
2. **Replay**: `rr replay -- -nx -iex 'set auto-load off' -iex 'set auto-load safe-path /dev/null'` (enters gdb interface with reverse execution). The flags after `--` go to gdb and disable auto-load with no trusted directory: the recorded binary is untrusted, and a permissive gdb config (e.g. an operator `~/.gdbinit` widening `auto-load safe-path`) would otherwise execute scripts the binary or its build tree plants (.debug_gdb_scripts, *-gdb.py). Same hardening set as scripts/crash_trace.py, use it on EVERY manual replay.

## Reverse Execution Commands

All standard gdb commands work, plus reverse variants:

- `reverse-next` / `rn`: Step back over function calls
- `reverse-step` / `rs`: Step back into functions
- `reverse-continue` / `rc`: Continue backward to previous breakpoint
- `reverse-stepi` / `rsi`: Step back one instruction
- `reverse-nexti` / `rni`: Step back over one instruction

## Crash Trace Extraction

### Regular Crashes

After `rr record <crashing-program>`:

The rest: https://github.com/gadievron/raptor/blob/HEAD/.claude/skills/crash-analysis/rr-debugger/SKILL.md