Create or update a secret at secret/data/{path} in Vault KV v2.
AI agents use create_secret to create or update resources in HashiCorp Vault MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your HashiCorp Vault MCP Server environment.
This tool creates or updates secrets in Vault, which are reversible write operations. While modifying secrets is sensitive (high severity due to potential impact on application authentication and security), it is not destructive (secrets can be updated again) and not financial.
From the tool's definition Tool description states 'Create or update a secret' which explicitly indicates data modification. The path parameter 'secret/data/{path}' shows this operates on Vault's secret storage system.
Documented attack patterns abuse exactly the kind of access create_secret gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and HashiCorp Vault MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for create_secret:
{
"version": "1",
"default": "deny",
"tools": {
"create_secret": {
"limits": [
{
"counter": "create_secret_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}create_secret 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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Create or update a secret at secret/data/{path} in Vault KV v2. It is categorised as a Write tool in the HashiCorp Vault MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the HashiCorp Vault MCP Server MCP server in PolicyLayer and add a rule for create_secret: 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 HashiCorp Vault MCP Server. Nothing to install.
create_secret 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 create_secret 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 create_secret. 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.
create_secret is provided by the HashiCorp Vault MCP Server MCP server (rccyx/vault-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from HashiCorp Vault 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 HashiCorp Vault MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.