Vault MCP server reference

This page contains reference information about the Vault MCP server, including configuration options and tools.

Available tools

The Vault MCP server provides specialized tools that AI models can use to access and perform certain Vault operations. These tools work automatically when you ask relevant questions—you don't need to invoke them manually.

Key-Value (kv) tools

Tool	Purpose	What it returns
`list_secrets`	List all secrets stored in Vault	A list of secret paths
`create_secret`	Create a new secret in Vault	Confirmation of the secret creation
`read_secret`	Retrieve the value of a specific secret	The secret value
`delete_secret`	Delete a specific secret from Vault	Confirmation of the secret deletion

Example prompt: "How can I securely store and access an API key for my application?"

Public Key Infrastructure (pki) tools

Tool	Purpose	What it returns
`create_pki_issuer`	Create a new PKI issuer in Vault	Confirmation of the PKI issuer creation
`create_pki_role`	Create a new PKI role in Vault	Confirmation of the PKI role creation
`delete_pki_role`	Delete a specific PKI role from Vault	Confirmation of the PKI role deletion
`enable_pki`	Enable the PKI secrets engine in Vault	Confirmation of the PKI engine enablement
`issue_pki_certificate`	Issue a new certificate from a PKI role	The issued certificate details
`list_pki_issuers`	List all PKI issuers in Vault	A list of PKI issuers
`list_pki_roles`	List all PKI roles in Vault	A list of PKI roles
`read_pki_issuer`	Retrieve details of a specific PKI issuer	Details of the PKI issuer
`read_pki_role`	Retrieve details of a specific PKI role	Details of the PKI role

Example prompt: "Show me how to issue pki certificate using the app-dev role."

System (sys) tools

Tool	Purpose	What it returns
`list_mounts`	List all mounts in Vault	A list of mount paths and their configurations
`create_mount`	Create a new KV mount (v1 or v2) in Vault	Confirmation of the mount creation
`delete_mount`	Delete a specific mount from Vault	Confirmation of the mount deletion

Example prompt: "Create a KV mount named "secrets" to store arbitrary secrets"

Transport protocols

You can set one of the following transport protocols when starting the MCP server so that it operates correctly for your environment.

Transport	Best for	How it works	Usage
`stdio`	Local development and direct integration with MCP clients	Uses standard input/output for JSON-RPC message communication	Automatically used when no specific transport mode is configured
`streamable-http`	Distributed setups, internal environments	HTTP-based transport with support for both direct HTTP requests	Enable by setting `TRANSPORT_MODE=streamable-http`

HTTP mode configuration

At this stage, the MCP server is intended for local use only. If using the StreamableHTTP transport in production, always configure the MCP_ALLOWED_ORIGINS environment variable to restrict access to trusted origins only. This helps prevent DNS rebinding attacks and other cross-origin vulnerabilities.

In HTTP mode, Vault configuration can be provided through multiple methods (in order of precedence):

HTTP Query: VAULT_ADDR
HTTP Headers: VAULT_ADDR, X-Vault-Token, and X-Vault-Namespace
Environment Variables: Standard VAULT_ADDR, VAULT_TOKEN, and VAULT_NAMESPACE env vars

Environment variables

You can set the following environment variables to configure the server behavior.

Variable	Purpose	Default value	Example	Options
`VAULT_ADDR`	Vault server address	`http://127.0.0.1:8200`	`http://vault.example.com:8200`	Any valid Vault server address
`VAULT_TOKEN`	Vault authentication token (required)	—	`hvs.xxxxxxxx`	Any valid Vault token
`VAULT_NAMESPACE`	Vault namespace (optional)	—	`admin`	Any valid Vault namespace
`TRANSPORT_MODE`	Set to `http` to enable HTTP mode	—	`http`	`http`
`TRANSPORT_HOST`	Host to bind to for HTTP mode	`127.0.0.1`	`0.0.0.0`	Any valid IP address
`TRANSPORT_PORT`	Port for HTTP mode	`8080`	`3000`	Any valid port number
`MCP_ENDPOINT`	HTTP server endpoint path	`/mcp`	`/api/mcp`	Any valid endpoint path
`MCP_ALLOWED_ORIGINS`	Comma-separated list of allowed origins for CORS	`""` (none)	`http://mcp.client.com:5000`.	Comma-separated list of origins or `""`
`MCP_CORS_MODE`	CORS mode: `strict`, `development`, or `disabled`	`strict`	`development`	`strict`, `development`, `disabled`
`MCP_TLS_CERT_FILE`	Location of the TLS certificate file	`""`	`/path/to/cert.pem`	Any valid file path
`MCP_TLS_KEY_FILE`	Location of the TLS key file	`""`	`/path/to/key.pem`	Any valid file path
`MCP_RATE_LIMIT_GLOBAL`	Global rate limit (format: rps:burst)	`10:20`	`100:200`	Any valid rps:burst value
`MCP_RATE_LIMIT_SESSION`	Per-session rate limit (format: rps:burst)	`5:10`	`20:40`	Any valid rps:burst value