AI agents use memory_save to create or update resources in Cortex — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Cortex environment.
The tool saves/persists data to the memory system (Obsidian vault). This is a reversible write operation—data can be retrieved, modified, or removed later. No description provided, which slightly reduces confidence, but the name and server context clearly indicate data creation/modification rather than deletion or execution of arbitrary code.
From the tool's definition Tool name 'memory_save' combined with server description indicating persistent storage of markdown lessons in an Obsidian vault.
Documented attack patterns abuse exactly the kind of access memory_save gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Cortex, and nothing reaches the server without passing your rules. This is the rule we recommend for memory_save:
{
"version": "1",
"default": "deny",
"tools": {
"memory_save": {
"limits": [
{
"counter": "memory_save_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}memory_save 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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memory_save. It is categorised as a Write tool in the Cortex MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Cortex MCP server in PolicyLayer and add a rule for memory_save: 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 Cortex. Nothing to install.
memory_save 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 memory_save 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 memory_save. 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.
memory_save is provided by the Cortex MCP server (tt-wang/memem). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 14 Cortex tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
14 Cortex tools catalogued and risk-classified — across an index of 42,500+ MCP servers.