Run a long-running command (e.g. npm test, cargo build) with streaming output. Unlike workspace_exec, this starts the command in the background and polls for output, so you get the full build log even for commands that take minutes. Max 5 minutes timeout. Use workspace_exec for quick commands (<3...
Risk signalsAccepts freeform code/query input (command)
Part of the ArcAgent MCP server.
Free to start. No card required.
AI agents invoke workspace_exec_stream to trigger processes or run actions in ArcAgent MCP. Execute operations can have side effects beyond the immediate call -- triggering builds, sending notifications, or starting workflows. Rate limits and argument validation are essential to prevent runaway execution.
workspace_exec_stream can trigger processes with real-world consequences. An uncontrolled agent might start dozens of builds, send mass notifications, or kick off expensive compute jobs. PolicyLayer enforces rate limits and validates arguments to keep execution within safe bounds.
Execute tools trigger processes. Rate-limit and validate arguments to prevent unintended side effects.
{
"version": "1",
"default": "deny",
"tools": {
"workspace_exec_stream": {
"limits": [
{
"counter": "workspace_exec_stream_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}See the full ArcAgent MCP policy for all 45 tools.
These attack patterns abuse exactly the kind of access workspace_exec_stream gives an agent. Each links to the full case and the policy that stops it:
Other execute tools across the catalogue. The same approach applies to each: rate-limit and validate the arguments.
Run a long-running command (e.g. npm test, cargo build) with streaming output. Unlike workspace_exec, this starts the command in the background and polls for output, so you get the full build log even for commands that take minutes. Max 5 minutes timeout. Use workspace_exec for quick commands (<30s).. It is categorised as a Execute tool in the ArcAgent MCP MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the ArcAgent MCP server in PolicyLayer and add a rule for workspace_exec_stream: 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 ArcAgent MCP. Nothing to install.
workspace_exec_stream 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 workspace_exec_stream 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 workspace_exec_stream. 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.
workspace_exec_stream is provided by the ArcAgent MCP server (araujota/arcagent). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 45 ArcAgent MCP tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
4,600+ MCP servers and 31,000+ tools scanned and risk-classified.