Lldb

What it does

When your agent uses it

• Debugging with LLDB on macOS
• Linux-clang environments
• Mapping GDB mental models to LLDB commands
• Using LLDB in Xcode

Example prompts

• “/lldb”

Requirements

• Python 3

Workflow steps

9 steps, taken from the step headings in SKILL.md.

1. 1Start LLDB
2. 2GDB → LLDB command map
3. 3Breakpoints
4. 4Inspect state
5. 5Watchpoints
6. 6Threads
7. 7macOS / Apple specifics
8. 8VS Code integration
9. 9LLDB Python scripting

What it can do on your machine

Read from SKILL.md and the folder at commit bdc5847. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves nothing: there is no allowed-tools line, so your agent's usual permission prompts apply.

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  No scripts in the folder and no shell commands in SKILL.md (its code samples are lldb, bash, json and python).

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  Links to these hosts (documentation or services it may open):

  • lldb.llvm.org

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Lldb loads about 1.4k tokens when it runs, and up to ~2.4k if it reads all its reference files. Until then it costs about 104 tokens; SKILL.md has 281 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~104

When it runs · the whole SKILL.md, loaded when a task matches

~1.4k

With references · SKILL.md plus every file in references/, read only if the agent opens them

~2.4k

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from mohitmishra786/low-level-dev-skills at commit bdc5847, republished under its MIT licence (© mohitmishra786). 281 words, ~1,426 tokens.

name

lldb

description

LLDB debugger skill for C/C++/Swift/Objective-C programs. Use when debugging with LLDB on macOS, FreeBSD, or Linux-clang environments, mapping GDB mental models to LLDB commands, using LLDB in Xcode or VS Code, or debugging Swift/Objective-C. Activates on queries about LLDB commands, GDB to LLDB migration, Apple platform debugging, LLDB Python scripting, or IDE-integrated debugging with clang-built binaries.

user-invocable

true

triggers

debug with LLDB, GDB to LLDB migration, LLDB commands, debug Swift with LLDB, LLDB in Xcode, LLDB Python scripting, Apple platform debugging LLDB, LLDB VS…

lldb ./prog                         # load binary
lldb ./prog -- arg1 arg2            # with arguments
lldb -p 12345                       # attach to PID
lldb -c core.1234                   # load core dump
lldb ./prog core.1234               # binary + core

# By name
b main
breakpoint set --name foo
breakpoint set --name foo --condition 'x > 0'

# By file:line
b file.c:42
breakpoint set --file file.c --line 42

# By address
b -a 0x100003f20

# By regex
breakpoint set --func-regex '^MyClass::'

# List
breakpoint list / br l

# Delete
breakpoint delete 2

# Disable/enable
breakpoint disable 1
breakpoint enable 1

# Commands on hit
breakpoint command add 1
  > p x
  > continue
  > DONE

# Print variable
p x
frame variable x
p *ptr
p arr[0]

# Print expression
expression x * 2 + 1
expr (int)sqrt(9.0)

# All locals
frame variable
fr v -a          # include arguments

# Registers
register read
register read rip rsp

# Memory
memory read --size 4 --format x --count 10 0x7fff0000
x/10xw 0x7fff0000          # GDB-compatible syntax

# Type info
image lookup --type MyClass
type lookup MyClass

watchpoint set variable x           # write watchpoint
watchpoint set variable -w read x   # read watchpoint
watchpoint set variable -w read_write x
watchpoint set expression -- &x     # by address

watchpoint list
watchpoint delete 1

thread list
thread select 3
thread backtrace all
thread backtrace --count 5           # limit depth

# Per-thread stepping
thread step-over                     # step this thread only

# Symbol lookup in shared cache
image lookup --address 0x18ab12345
image lookup --name objc_msgSend

# Objective-C method breakpoint
b "-[NSArray objectAtIndex:]"
b "+[NSString stringWithFormat:]"

# Inspect Objective-C object
po myObject                          # print-object (calls -description)
po [arr count]

# Show loaded libraries
image list
image list -b                        # brief (names only)

{
  "version": "0.2.0",
  "configurations": [
    {
      "name": "Debug (lldb)",
      "type": "lldb",
      "request": "launch",
      "program": "${workspaceFolder}/build/prog",
      "args": [],
      "cwd": "${workspaceFolder}",
      "preLaunchTask": "build"
    }
  ]
}

import lldb

def print_all_threads(debugger, command, result, internal_dict):
    target = debugger.GetSelectedTarget()
    process = target.GetProcess()
    for thread in process:
        print(f"Thread {thread.GetIndexID()}: {thread.GetName()}")
        for frame in thread:
            print(f"  {frame}")

def __lldb_init_module(debugger, internal_dict):
    debugger.HandleCommand('command script add -f myscript.print_all_threads pthreads')

© mohitmishra786, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 1 other file (references) in skills/debuggers/lldb of mohitmishra786/low-level-dev-skills.

• SKILL.md
• references/gdb-lldb-map.md

Open the folder on GitHubat commit bdc5847