AI agents use memory_modify to create or update resources in Neo4j Memory Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Neo4j Memory Server environment.
The 'memory_modify' tool modifies existing graph data in a persistent memory system. This is a reversible write operation—data can be corrected or updated. It does not delete (would be Destructive), execute arbitrary code (would be Execute), or involve financial transactions.
From the tool's definition Tool name 'memory_modify' indicates modification of stored data. The server description confirms this tool operates on a persistent Neo4j graph database storing memory, relationships, and knowledge.
Documented attack patterns abuse exactly the kind of access memory_modify gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Neo4j Memory Server, and nothing reaches the server without passing your rules. This is the rule we recommend for memory_modify:
{
"version": "1",
"default": "deny",
"tools": {
"memory_modify": {
"limits": [
{
"counter": "memory_modify_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}memory_modify 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_modify. It is categorised as a Write tool in the Neo4j Memory Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Neo4j Memory Server MCP server in PolicyLayer and add a rule for memory_modify: 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 Neo4j Memory Server. Nothing to install.
memory_modify 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_modify 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_modify. 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_modify is provided by the Neo4j Memory Server MCP server (sylweriusz/mcp-neo4j-memory-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 4 Neo4j Memory Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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4 Neo4j Memory Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.