AI agents use update_document to create or update resources in Memory Bank MCP — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Memory Bank MCP environment.
The tool modifies existing documents in a structured knowledge management system. This is a Write-category action because: (1) it changes data reversibly, (2) the operation can be undone or corrected by subsequent updates, and (3) it lacks the permanence of Destructive actions or side effects of Execute actions.
From the tool's definition Tool name 'update_document' indicates modification of existing data within the memory bank system. The server description confirms this is a 'project documentation' management system where 'create, manage, and access' operations are performed.
Documented attack patterns abuse exactly the kind of access update_document gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Memory Bank MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for update_document:
{
"version": "1",
"default": "deny",
"tools": {
"update_document": {
"limits": [
{
"counter": "update_document_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}update_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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update_document. It is categorised as a Write tool in the Memory Bank MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Memory Bank MCP server in PolicyLayer and add a rule for update_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. Nothing to install.
update_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 update_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 update_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.
update_document is provided by the Memory Bank MCP server (tuncer-byte/memory-bank-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 5 Memory Bank MCP tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
5 Memory Bank MCP tools catalogued and risk-classified — across an index of 42,500+ MCP servers.