AI agents use save_message to create or update resources in Membase MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Membase MCP Server environment.
This tool creates or modifies messages in persistent storage on the Unibase DA network. It is a Write operation because it persistently records data that can be later retrieved and modified.
From the tool's definition Tool name 'save_message' indicates creation/modification of message data. Server description emphasizes 'store and retrieve memory persistently,' confirming Write operations. Tool description is empty, reducing confidence slightly.
Documented attack patterns abuse exactly the kind of access save_message gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Membase MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for save_message:
{
"version": "1",
"default": "deny",
"tools": {
"save_message": {
"limits": [
{
"counter": "save_message_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}save_message 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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save_message. It is categorised as a Write tool in the Membase MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Membase MCP Server MCP server in PolicyLayer and add a rule for save_message: 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 Membase MCP Server. Nothing to install.
save_message 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 save_message 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 save_message. 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.
save_message is provided by the Membase MCP Server MCP server (unibaseio/membase-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Membase MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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4 Membase MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.