devcontainer_exec
Execute an arbitrary shell command inside the devcontainer for the specified workspace folder.Use this to run custom commands or scripts within the devcontainer context.
LABSCO SUMMARY
The container lifecycle collapses to three calls with an order to them.
devcontainer_up comes first and exists to guarantee the container is running before anything executes inside it; devcontainer_run_user_commands then plays the setup scripts the configuration defines; devcontainer_exec covers everything after that. Because workspaceFolder is a per-call argument rather than server configuration, one client can drive several checkouts at once. Output redirection is built into each tool through outputFilePath, which is what keeps a long build from arriving as one enormous message.
What it is
A three-tool wrapper over the devcontainer lifecycle for a workspace folder on disk.
What you get
- devcontainer_up starts or initializes the devcontainer for the workspace folder you name, leaving it running and ready.
- devcontainer_run_user_commands runs that devcontainer's postCreateCommand and postStartCommand scripts.
- devcontainer_exec runs an arbitrary shell command inside the container for that workspace folder.
- All three take an outputFilePath, so the output of a call can land in a file instead of coming back inline.
Requirements
A workspace folder on disk with a devcontainer configuration, named per call as workspaceFolder.
Setup effort
One command — npx -y @crunchloop/mcp-devcontainers
USE CASES
01
Taking a fresh checkout to the point where its tests can run
Bring the devcontainer up for the workspace folder, then run the setup scripts the configuration defines rather than reconstructing them by hand.
02
Running a command in the project's environment instead of your own
Execute the build, test or script inside the container that the project defines, with output written to a file when it is long.
3 tools
Counted once with only startup setup. Other versions, modes or optional credentials may expose a different list.
devcontainer_run_user_commands
Run the user-defined postCreateCommand and postStartCommand scripts in the devcontainerfor the specified workspace folder. Use this to execute setup or initialization commandsafter the devcontainer starts.
devcontainer_up
Start or initialize a devcontainer environment in the specified workspace folder.Use this to ensure the devcontainer is running and ready for development tasks.
BEFORE YOU INSTALL
What to know first
Tools you get
3 tools when we connected.
Requires
npx on PATH
CONTEXT COST
Light Standing cost
Rated by the size of the 3 tool definitions that ride along on every turn, not by how many there are
INSTALLATION
Connect your client
Add the block to your client, or run the command directly.
Server setup
Configuration file
JSON
{
"mcpServers": {
"mcp-devcontainers": {
"command": "npx",
"args": [
"-y",
"@crunchloop/mcp-devcontainers"
]
}
}
}npx
TERMINAL
npx -y @crunchloop/mcp-devcontainers
