AI agents use vault_promote to create or update resources in Vault — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Vault environment.
The 'promote' action in a knowledge management context typically means moving, reorganizing, or elevating content (e.g., promoting a note to a higher level, changing its visibility, or advancing its status). This is a write operation as it modifies data structure or metadata reversibly.
From the tool's definition Tool name 'vault_promote' within a knowledge management system, paired with sibling tools like vault_capture, vault_read, and vault_reflect. The name suggests elevating or modifying the status/organization of stored information.
Documented attack patterns abuse exactly the kind of access vault_promote gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Vault, and nothing reaches the server without passing your rules. This is the rule we recommend for vault_promote:
{
"version": "1",
"default": "deny",
"tools": {
"vault_promote": {
"limits": [
{
"counter": "vault_promote_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}vault_promote 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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vault_promote. It is categorised as a Write tool in the Vault MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Vault MCP server in PolicyLayer and add a rule for vault_promote: 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 Vault. Nothing to install.
vault_promote 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 vault_promote 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 vault_promote. 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.
vault_promote is provided by the Vault MCP server (oliverxuzy-ai/knowledge-in-a-vat). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Vault, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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7 Vault tools catalogued and risk-classified — across an index of 43,000+ MCP servers.