AI agents use add_prompt to create or update resources in MCP Prompts Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your MCP Prompts Server environment.
The tool creates (adds) prompt data reversibly within a templating system. While the description is empty, the name and server context strongly indicate a Write operation. Severity is medium rather than low because an AI agent could be manipulated into adding malicious or misleading prompts that could influence downstream usage.
From the tool's definition Tool name 'add_prompt' and server description indicating 'creation, management, and templating of prompts' suggest this tool creates or adds new prompt entries.
Documented attack patterns abuse exactly the kind of access add_prompt 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 add_prompt:
{
"version": "1",
"default": "deny",
"tools": {
"add_prompt": {
"limits": [
{
"counter": "add_prompt_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}add_prompt stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
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add_prompt. It is categorised as a Write tool in the MCP Prompts Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the MCP Prompts Server MCP server in PolicyLayer and add a rule for add_prompt: 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.
add_prompt is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the add_prompt 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 add_prompt. 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.
add_prompt 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.