Write a document to a branch or global memory bank
AI agents use write_document to create or update resources in Memory Bank MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Memory Bank MCP Server environment.
This tool creates or modifies documents in a memory bank system, which is reversible (documents can be edited or deleted later). It does not delete or irreversibly destroy data, nor does it execute arbitrary code or move money.
From the tool's definition Tool name is 'write_document' and description states 'Write a document to a branch or global memory bank', indicating creation or modification of persistent data in storage.
Documented attack patterns abuse exactly the kind of access write_document gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Memory Bank MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for write_document:
{
"version": "1",
"default": "deny",
"tools": {
"write_document": {
"limits": [
{
"counter": "write_document_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}write_document 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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Write a document to a branch or global memory bank. It is categorised as a Write tool in the Memory Bank MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Memory Bank MCP Server MCP server in PolicyLayer and add a rule for write_document: 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 Memory Bank MCP Server. Nothing to install.
write_document 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 write_document 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 write_document. 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.
write_document is provided by the Memory Bank MCP Server MCP server (t3ta/memory-bank-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Memory Bank MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
4 Memory Bank MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.