tashfeenahmed Bash Skill
Execute shell commands in the workspace directory with output capture and timeout handling.
When to Use
Use the bash skill for:
- Running commands: Execute shell commands like
ls,npm,git, etc. - Checking system state: Check file existence, disk space, process status
- File operations: Move, copy, delete files (when dedicated file skills aren't appropriate)
- Package management: Install dependencies, run build scripts
- Testing: Run test suites, linters, type checkers
Input Format
The skill accepts JSON arguments via the SKILL_ARGS environment variable:
{
"command": "echo 'Hello World'",
"timeout": 60000,
"cwd": "/path/to/directory"
}
Parameters
| Parameter | Type | Required | Default | Description |
|---|---|---|---|---|
command |
string | Yes | - | The bash command to execute |
timeout |
number | No | 60000 | Timeout in milliseconds |
cwd |
string | No | workspace | Working directory for execution |
max_output |
number | No | 30720 | Max output bytes. Increase for long test runs or large search results. Max: 204800 |
Output Format
The skill returns JSON to stdout:
{
"success": true,
"output": "command output here",
"error": "stderr content if any",
"exitCode": 0
}
Response Fields
| Field | Type | Description |
|---|---|---|
success |
boolean | True if command exited with code 0 |
output |
string | Captured stdout (truncated at max_output limit, default 30KB) |
error |
string | Captured stderr or error message |
exitCode |
number | Process exit code |
Safety Considerations
- No interactive commands: Commands requiring user input will hang or fail
- Avoid destructive operations: Always confirm before
rm -rf,git reset --hard, etc. - Sensitive data: Don't echo secrets or credentials to output
- Long-running processes: Use appropriate timeouts; default is 60 seconds
- Resource limits: Output is truncated at 30KB by default (adjustable via
max_output, up to 200KB) - HTTP writes: Mutating
curlcalls must include--fail-with-body(or-f) so a 4xx/5xx response cannot be mistaken for success
Security Features
The bash skill includes basic protections against accidental damage:
Dangerous Command Blocking
The following patterns are automatically blocked with exit code 126:
rm -rf /and variations (root filesystem removal)--no-preserve-rootflag (bypassing safety)- Fork bombs like
:(){ :|:& };: - Direct device access (
/dev/sda,/dev/nvme, etc.) - Filesystem formatting (
mkfscommands) ddwrites to raw devices- Writes to system directories (
/etc,/boot,/sys,/proc)
Path Restrictions
The cwd parameter is validated to prevent escaping the workspace:
- Path traversal with
../that escapes workspace is blocked - Symlinks that resolve outside workspace are blocked
- All paths are resolved relative to the workspace root
Note: These are basic protections to prevent obvious accidents, not a security sandbox. They don't protect against determined malicious use.
Examples
Check directory contents
{ "command": "ls -la" }
Run tests with timeout
{
"command": "npm test",
"timeout": 120000
}
Execute in specific directory
{
"command": "git status",
"cwd": "/path/to/repo"
}
Check Node.js version
{ "command": "node --version" }