Configuration Outside VS Code

Using launch.json Standalone

The CLI reads the same launch.json as VS Code. Most configurations work without modification. The CLI looks for launch.json in .vscode/launch.json relative to the current directory, or at the path specified by the -j flag.

Variable Resolution

Variables resolved by the CLI:

Variable	Resolves to
${workspaceFolder}	Directory containing launch.json
${env:VAR}	Environment variable, or envFile entry
${userHome}	User home directory
${pathSeparator}	/ on Linux/macOS, \ on Windows
${config:KEY}	Value from .vscode/settings.json

Variables not supported in CLI mode:

Variable	Reason
${command:...}	Requires VS Code extension runtime. Expand manually before using.
${input:...}	Requires VS Code UI prompt. Expand manually before using.

envFile

The envFile property loads variables from a name=value file:

# .env
TOOLCHAIN=/usr/local/arm-none-eabi
GDB=${TOOLCHAIN}/bin/arm-none-eabi-gdb
OPENOCD=/usr/bin/openocd

{
  "envFile": "${workspaceFolder}/.env",
  "gdbPath": "${env:GDB}",
  "serverPath": "${env:OPENOCD}"
}

The envFile is loaded first, so its variables are available throughout the configuration.

settings.json

For ${config:mcu-debug.KEY} references, use your .vscode/settings.json in the project or create your own JSON file:

{
  "mcu-debug.armToolchainPath": "/usr/local/arm-none-eabi/bin",
  "mcu-debug.openocdPath": "/usr/local/bin"
}

Then reference these in launch.json:

{
  "gdbPath": "${config:mcu-debug.armToolchainPath}/arm-none-eabi-gdb",
  "serverPath": "${config:mcu-debug.openocdPath}/openocd"
}

When you save workspace settings in VS Code, the extension writes this file automatically, keeping CLI and VS Code settings in sync.

For user-global settings (not project-specific), create ~/.mcu-debug/settings.json with the same format.

Diagnosing Configuration

Print the fully-resolved configuration with all variables substituted:

mcu-debug dump-config "Launch PSoC6 CM4"

Show which variables were substituted (diff mode):

mcu-debug dump-config "Launch PSoC6 CM4" --diff

Use this to verify paths are resolving correctly before starting a session.