Spawn a new Claude instance with role and context
AI agents invoke spawn to trigger actions in tmux-claude MCP Server. 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.
This tool launches new AI agent processes (Claude instances) with configurable roles and context. Spawning new processes is an Execute-category action. Misuse could result in uncontrolled proliferation of agent instances, resource exhaustion, or agents performing unauthorized actions — hence high severity.
From the tool's definition Spawn a new Claude instance with role and context
Documented attack patterns abuse exactly the kind of access spawn gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and tmux-claude MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for spawn:
{
"version": "1",
"default": "deny",
"tools": {
"spawn": {
"limits": [
{
"counter": "spawn_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}spawn 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.
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Spawn a new Claude instance with role and context. It is categorised as a Execute tool in the tmux-claude MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the tmux-claude MCP Server MCP server in PolicyLayer and add a rule for spawn: 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 tmux-claude MCP Server. Nothing to install.
spawn 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 spawn 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 spawn. 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.
spawn is provided by the tmux-claude MCP Server MCP server (michael-abdo/tmux-claude-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from tmux-claude MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
26 tmux-claude MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.