HashiCorp Vault + Vault MCP Server vs Infisical

HashiCorp Vault + Vault MCP Server

Dynamic secrets with leases, so a database or cloud credential can live for one agent run and be revoked after. The MCP server's newest build is 0.2.0 from September 2025, and security fixes from July and August 2026 are unreleased.

Infisical

Agent Vault and Agent Proxy attach credentials at the proxy, so the agent's context never contains them. Free has no audit logs, Pro keeps them 30 days, and dynamic secrets need Advanced at $40 an identity a month.

HashiCorp Vault + Vault MCP Server

1. Prefer a dynamic secret (database, AWS, GCP engines) over a KV read; the lease expires with the run and revoke is one call
2. Log in with AppRole or Kubernetes auth and keep the token for its TTL. Renew with auth/token/renew-self rather than logging in per request
3. For KV v2, GET /v1/<mount>/data/<path> and read data.data, and pass cas on writes so a retry can't overwrite a newer version
4. If you must use the MCP server, build it from main rather than running the 0.2.0 image, run it over stdio, and give it a token limited to one mount
5. Ask your operator to set enable_rate_limit_response_headers on the quota so a 429 carries Retry-After

Infisical

1. Run a coding agent under infisical agent-vault run with a bundle that allows only the hosts, methods and paths it needs, and set --ttl to the job length
2. Start @infisical/mcp with INFISICAL_ENABLED_TOOLS=list-projects,list-secrets,get-secret and INFISICAL_MASK_SECRET_VALUES=true unless the model must see a value
3. Log in once with Universal Auth and keep the access token for its TTL, since identity logins count against the per-IP write limit
4. Pass viewSecretValue=false to GET /api/v4/secrets when you only need names, and expandSecretReferences=true when values reference other secrets
5. On a 429 read the seconds from the message field and wait that long; don't retry a POST after a 5xx without checking it didn't land