GDB CLI for AI

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A GDB debugging tool designed for AI Agents (Claude Code, etc.). Uses a "thin client CLI + GDB built-in Python RPC Server" architecture, enabling stateful GDB debugging through Bash.

Features

• Core Dump Analysis: Load core dumps with symbols resident in memory for millisecond-level response
• Live Attach Debugging: Attach to running processes with non-stop mode support
• Structured JSON Output: All commands output JSON with automatic truncation/pagination and operation hints
• Security Mechanisms: Command whitelist, heartbeat timeout auto-cleanup, idempotency guarantees
• Database-Optimized: scheduler-locking, large object pagination, multi-thread truncation

Requirements

• Python: 3.6.8+
• GDB: 9.0+ with Python support enabled
• OS: Linux

Check GDB Python Support

# Check if GDB has Python support
gdb -nx -q -batch -ex "python print('OK')"

# If system GDB lacks Python, check GCC Toolset (RHEL/CentOS)
/opt/rh/gcc-toolset-13/root/usr/bin/gdb -nx -q -batch -ex "python print('OK')"

Installation

# Install from PyPI
pip install gdb-cli

# Or install from GitHub
pip install git+https://github.com/Cerdore/gdb-cli.git

# Or clone and install locally
git clone https://github.com/Cerdore/gdb-cli.git
cd gdb-cli
pip install -e .

Environment check

gdb-cli env-check

## Quick Start

### 1. Load Core Dump

```bash
gdb-cli load --binary ./my_program --core ./core.12345

Output:

{
  "session_id": "f465d650",
  "mode": "core",
  "binary": "./my_program",
  "core": "./core.12345",
  "gdb_pid": 12345,
  "status": "started"
}

If your system's default GDB doesn't have Python support, specify it with --gdb-path:

gdb-cli load --binary ./my_program --core ./core.12345 \
  --gdb-path /opt/rh/gcc-toolset-13/root/usr/bin/gdb

2. Debugging Operations

All operations use --session / -s to specify the session ID:

SESSION="f465d650"

# List threads
gdb-cli threads -s $SESSION

# Get backtrace (default: current thread)
gdb-cli bt -s $SESSION

# Get backtrace for a specific thread
gdb-cli bt -s $SESSION --thread 3

# Evaluate C/C++ expressions
gdb-cli eval-cmd -s $SESSION "my_struct->field"

# Access array elements
gdb-cli eval-element -s $SESSION "my_array" --index 5

# View local variables
gdb-cli locals-cmd -s $SESSION

# Execute raw GDB commands
gdb-cli exec -s $SESSION "info registers"

# Check session status
gdb-cli status -s $SESSION

3. Session Management

# List all active sessions
gdb-cli sessions

# Stop a session
gdb-cli stop -s $SESSION

4. Live Attach Debugging

# Attach to a running process (default: scheduler-locking + non-stop)
gdb-cli attach --pid 9876

# Attach with symbol file
gdb-cli attach --pid 9876 --binary ./my_program

# Allow memory modification and function calls
gdb-cli attach --pid 9876 --allow-write --allow-call

Full Command Reference

load — Load Core Dump

gdb-cli load --binary <path> --core <path> [options]

  --binary, -b      Executable file path (required)
  --core, -c        Core dump file path (required)
  --sysroot         sysroot path (for cross-machine debugging)
  --solib-prefix    Shared library prefix
  --source-dir      Source code directory
  --timeout         Heartbeat timeout in seconds (default: 600)
  --gdb-path        GDB executable path (default: "gdb")

attach — Attach to Process

gdb-cli attach --pid <pid> [options]

  --pid, -p               Process PID (required)
  --binary                Executable file path (optional)
  --scheduler-locking     Enable scheduler-locking (default: true)
  --non-stop              Enable non-stop mode (default: true)
  --timeout               Heartbeat timeout in seconds (default: 600)
  --allow-write           Allow memory modification
  --allow-call            Allow function calls

threads — List Threads

gdb-cli threads -s <session> [options]

  --range           Thread range, e.g., "3-10"
  --limit           Maximum return count (default: 20)
  --filter-state    Filter by state ("running" / "stopped")

bt — Backtrace

gdb-cli bt -s <session> [options]

  --thread, -t      Specify thread ID
  --limit           Maximum frame count (default: 30)
  --full            Include local variables
  --range           Frame range, e.g., "5-15"

eval-cmd — Evaluate Expression

gdb-cli eval-cmd -s <session> <expr> [options]

  --max-depth       Recursion depth limit (default: 3)
  --max-elements    Array element limit (default: 50)

eval-element — Access Array/Container Elements

gdb-cli eval-element -s <session> <expr> --index <N>

exec — Execute Raw GDB Command

gdb-cli exec -s <session> <command>

  --safety-level    Safety level (readonly / readwrite / full)

thread-apply — Batch Thread Operations

gdb-cli thread-apply -s <session> <command> --all
gdb-cli thread-apply -s <session> <command> --threads "1,3,5"

Output Examples

threads

{
  "threads": [
    {"id": 1, "global_id": 1, "state": "stopped"},
    {"id": 2, "global_id": 2, "state": "stopped"}
  ],
  "total_count": 5,
  "truncated": true,
  "current_thread": {"id": 1, "global_id": 1, "state": "stopped"},
  "hint": "use 'threads --range START-END' for specific threads"
}

eval-cmd

{
  "expression": "(int)5+3",
  "value": 8,
  "type": "int",
  "size": 4
}

bt

{
  "frames": [
    {"number": 0, "function": "crash_thread", "address": "0x400a1c", "file": "test.c", "line": 42},
    {"number": 1, "function": "start_thread", "address": "0x7f3fa2e13fa"}
  ],
  "total_count": 2,
  "truncated": false
}

Security Mechanisms

Command Whitelist (Attach Mode)

Safety Level	Allowed Commands
readonly (default)	bt, info, print, threads, locals, frame
readwrite	+ set variable
full	+ call, continue, step, next

quit, kill, shell, signal are always blocked.

Heartbeat Timeout

Automatically detaches and quits after 10 minutes of inactivity by default. Configurable via --timeout.

Idempotency

Only one session per PID / Core file is allowed. Repeated load/attach returns the existing session_id.

Cross-Machine Core Dump Debugging

When analyzing core dumps from other machines, shared library paths may differ:

# Set sysroot (path prefix replacement)
gdb-cli load --binary ./my_program --core ./core.1234 \
  --sysroot /path/to/target/rootfs

# Set source directory (for source-level debugging)
gdb-cli load --binary ./my_program --core ./core.1234 \
  --source-dir /path/to/source

Development

Project Structure

src/gdb_cli/
├── cli.py              # CLI entry point (Click)
├── client.py           # Unix Socket client
├── launcher.py         # GDB process launcher
├── session.py          # Session metadata management
├── safety.py           # Command whitelist filter
├── formatters.py       # JSON output formatting
├── env_check.py        # Environment check
├── errors.py           # Error classification
└── gdb_server/
    ├── gdb_rpc_server.py   # RPC Server core
    ├── handlers.py         # Command handlers
    ├── value_formatter.py  # gdb.Value serialization
    └── heartbeat.py         # Heartbeat timeout management

skills/
└── gdb-cli/               # Claude Code skill for intelligent debugging
    ├── SKILL.md            # Skill definition
    └── evals/              # Test cases for skill evaluation

Run Tests

pip install -e ".[dev]"
pytest tests/ -v

End-to-End Testing

Requires GDB with Python support. Use the crash test program in tests/crash_test/:

# Compile test program
cd tests/crash_test
gcc -g -pthread -o crash_test crash_test_c.c

# Generate coredump
ulimit -c unlimited
./crash_test  # Will SIGSEGV

# Find core file
ls /path/to/core_dumps/core-crash_test-*

# Run E2E test
gdb-cli load --binary ./crash_test --core /path/to/core \
  --gdb-path /opt/rh/gcc-toolset-13/root/usr/bin/gdb

Known Limitations

• No target remote support (use SSH for remote debugging, see below)
• No multi-inferior debugging support
• GDB 12.x Guile pretty printers are not thread-safe, workaround via format_string(raw=True)
• GDB embedded Python version may be older (e.g., 3.6.8), code has compatibility handling

Remote Debugging via SSH

Install and run on remote machine in one command:

ssh user@remote-host "pip install git+https://github.com/Cerdore/gdb-cli.git && gdb-cli load --binary ./my_program --core ./core.12345"

Or install first, then debug:

# Install on remote
ssh user@remote-host "pip install git+https://github.com/Cerdore/gdb-cli.git"

# Run debugging
ssh user@remote-host "gdb-cli load --binary ./my_program --core ./core.12345"

Claude Code Skills

This project includes a gdb-cli skill for Claude Code that provides intelligent debugging assistance by combining source code analysis with runtime state inspection.

Install the Skill

bunx skills add https://github.com/Cerdore/gdb-cli --skill=gdb-cli

Usage in Claude Code

/gdb-cli

# Or describe your debugging need:
I have a core dump at ./core.1234 and binary at ./myapp. Help me debug it.

Features

• Source Code Correlation: Automatically reads source files around crash points
• Deadlock Detection: Identifies circular wait patterns in multi-threaded programs
• Safety Warnings: Alerts about production environment risks when attaching to live processes
• Structured Reports: Generates analysis with root cause hypotheses and next steps

See skills/README.md for more details.

License

Apache License 2.0