This record as markdown: /tools/0sec/bash-exec.md
What bash_exec does on 0sec
AI agents invoke bash_exec to trigger actions in 0sec. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.
Why bash_exec is rated High
bash_exec triggers real processes with real consequences. An agent gone sideways doesn't fire it once. It starts dozens of builds, sends mass notifications, or burns through compute before anyone looks up.
Attacks that exploit this kind of access
The rule that runs bash_exec safely
PolicyLayer is an MCP gateway: it sits between your AI agents and 0sec, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For bash_exec, this is the rule to start with:
bash_exec stays usable, but rate-capped: a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect 0sec, apply this rule, and every bash_exec call is checked against it from then on.
Questions about bash_exec
Execute shell commands internally for diagnostics. It is categorised as a Execute tool in the 0sec MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the 0sec MCP server in PolicyLayer and add a rule for bash_exec: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches 0sec. Nothing to install.
bash_exec is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the bash_exec rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for bash_exec. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
bash_exec is provided by the 0sec MCP server (0sec-labs/0sec). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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