Execute a slash command to quickly apply a prompt template
AI agents invoke slash_command to trigger actions in MCP Prompts 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.
Executing slash commands is a form of code/command execution with side effects determined by the template content. While the server's primary purpose is prompt management, this tool triggers external operations at runtime. The high severity reflects that malicious prompt templates could cause unintended actions on the system or connected services.
From the tool's definition Tool description states 'Execute a slash command' — the verb 'execute' combined with 'slash command' indicates runtime invocation of commands whose effects depend on the prompt template argument.
Documented attack patterns abuse exactly the kind of access slash_command gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and MCP Prompts Server, and nothing reaches the server without passing your rules. This is the rule we recommend for slash_command:
{
"version": "1",
"default": "deny",
"tools": {
"slash_command": {
"limits": [
{
"counter": "slash_command_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}slash_command 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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Execute a slash command to quickly apply a prompt template. It is categorised as a Execute tool in the MCP Prompts Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the MCP Prompts Server MCP server in PolicyLayer and add a rule for slash_command: 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 MCP Prompts Server. Nothing to install.
slash_command 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 slash_command 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 slash_command. 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.
slash_command is provided by the MCP Prompts Server MCP server (sparesparrow/mcp-prompts). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 51 MCP Prompts Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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51 MCP Prompts Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.