run_commandExecute arbitrary shell commands on Ubuntu/Linux systems for tasks not covered by structured tools, returning stdout and stderr within a 30-second timeout.
Execute an arbitrary shell command and return stdout/stderr. Subject to 30s timeout and 1MB output limit. Use for operations not covered by structured tools.
| Name | Required | Description | Default |
|---|---|---|---|
| command | Yes | Shell command to execute |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=false, openWorldHint=true and destructiveHint=false. The description adds operationally important limits the annotations do not carry: a 30s timeout and a 1MB output cap, which materially affect how an agent designs a command.
Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.
Is the description appropriately sized, front-loaded, and free of redundancy?
Three short clauses, front-loaded with the action, then constraints, then routing advice. No sentence is filler and nothing needed for selection is buried.
Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.
Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?
For a one-param arbitrary-shell tool with annotations covering the safety profile and no output schema, the description supplies the timeout, output cap, and intended scope. The only meaningful omission is any privilege/auth distinction relative to run_command_sudo.
Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.
Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?
There is a single parameter and schema description coverage is 100%, so the schema already documents it fully; the baseline for that case is 3. The description adds no syntax, quoting, or shell-resolution guidance beyond the schema's 'Shell command to execute'.
Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.
Does the description clearly state what the tool does and how it differs from similar tools?
States a specific verb and resource ('Execute an arbitrary shell command') and names the return payload (stdout/stderr), which is more than a restatement of the name. It does not, however, distinguish itself from the sibling run_command_sudo, which an agent would need to route between.
Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.
Does the description explain when to use this tool, when not to, or what alternatives exist?
'Use for operations not covered by structured tools' gives a clear fallback condition that selects this tool over the many structured siblings. It stops short of an explicit when-not (e.g. preferring apt_install over shell apt) or any mention of the sudo variant.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.