Authenticate with vaults - Claude Platform Docs
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Authenticate with vaults

Register per-user credentials when creating sessions.

Vaults and credentials are authentication primitives that let you register credentials for third-party services once and reference them by ID at session creation. This means you don't need to run your own secret store, transmit tokens on every call, or lose track of which end user an agent acted on behalf of.

The vault reference is a per-session parameter, so you can manage your product at the agent resource granularity and your users at the session resource granularity.

Create a vault

A vault is the collection of credentials associated with an end user. Give it a display_name and optionally tag it with metadata so you can map it back to your own user records.

VAULT_ID=$(ant beta:vaults create --transform id --raw-output < alice.vault.yaml)
echo "$VAULT_ID"  # "vlt_01ABC..."
alice.vault.yaml
display_name: Alice
metadata:
  external_user_id: usr_abc123

The response is the full vault record:

{
  "type": "vault",
  "id": "vlt_01ABC...",
  "display_name": "Alice",
  "metadata": { "external_user_id": "usr_abc123" },
  "created_at": "2026-03-18T10:00:00Z",
  "updated_at": "2026-03-18T10:00:00Z",
  "archived_at": null
}

Add a credential

Two credential categories are supported:

  • MCP credentials (mcp_oauth, static_bearer): each credential is keyed by an mcp_server_url. When the agent connects to a server at that URL at session runtime, the token is injected automatically.
  • Environment variables (environment_variable): each credential is keyed by a secret_name (the environment variable name) and stored in the sandbox as an opaque placeholder. When the agent initiates an outbound request, the opaque placeholder is substituted with the real secret at egress. The agent never sees the secret value. Use this for any service that authenticates through an environment variable, such as CLIs, SDKs, or direct API calls.

The actual credential values you supply (token, access_token, refresh_token, client_secret, secret_value) are treated as sensitive, write-only fields and never returned in API responses.

Use mcp_oauth when the MCP server uses OAuth 2.0. If you supply a refresh block, Anthropic refreshes the access token on your behalf when it expires.

The refresh.token_endpoint_auth.type field indicates how to authenticate the refresh call:

  • none: public client
  • client_secret_basic: HTTP Basic authentication with the client secret
  • client_secret_post: client secret in the POST body
CREDENTIAL_ID=$(ant beta:vaults:credentials create \
  --vault-id "$VAULT_ID" \
  --display-name "Alice's Slack" \
  --transform id --raw-output <<'YAML'
auth:
  type: mcp_oauth
  mcp_server_url: https://mcp.slack.com/mcp
  access_token: xoxp-...
  expires_at: "2099-12-31T23:59:59Z"
  refresh:
    token_endpoint: https://slack.com/api/oauth.v2.access
    client_id: "1234567890.0987654321"
    scope: channels:read chat:write
    refresh_token: xoxe-1-...
    token_endpoint_auth:
      type: client_secret_post
      client_secret: abc123...
YAML
)

Credentials are stored as provided and are not validated until session runtime. An invalid credential surfaces as an authentication or downstream error during the session, which is emitted but does not block the session from continuing.

Constraints:

  • Unique key per vault. mcp_server_url (MCP credentials) and secret_name (environment variable credentials) must be unique among active credentials in a vault. Creating a duplicate returns a 409.
  • Keys are immutable. To change mcp_server_url or secret_name, archive the credential and create a new one.
  • Maximum 20 credentials per vault.

Reference the vault at session creation

Pass vault_ids when creating a session:

SESSION_ID=$(ant beta:sessions create \
  --agent "$AGENT_ID" \
  --environment-id "$ENVIRONMENT_ID" \
  --vault-id "$VAULT_ID" \
  --title "Alice's Slack digest" \
  --transform id --raw-output)

Runtime behavior:

  • When no MCP credential matches by mcp_server_url, the connection is attempted unauthenticated and will error if the server requires authentication.
  • When multiple vaults contain a matching credential, the first vault with a match wins.
  • In multiagent sessions, vault credentials apply to every thread. An agent whose own definition declares the matching MCP server authenticates with these credentials. See Connect agents to MCP servers.

Rotate a credential

Secret values, display_name, and (on environment variable credentials) injection_location can be updated. injection_location updates merge per field, as described in the Environment variable tab of Add a credential. For a running session, an injection_location update propagates the same way as a secret rotation: the session's credentials are re-resolved without a restart, as described in Credential lifecycle, and the updated locations apply to the session's subsequent outbound requests. Structural fields (mcp_server_url, secret_name, token_endpoint, client_id) are locked after creation. To change them, archive the credential and create a new one.

ant beta:vaults:credentials update \
  --vault-id "$VAULT_ID" \
  --credential-id "$CREDENTIAL_ID" <<'YAML'
auth:
  type: mcp_oauth
  access_token: xoxp-new-...
  expires_at: "2099-12-31T23:59:59Z"
  refresh:
    refresh_token: xoxe-1-new-...
YAML

Credential lifecycle

Credentials are re-resolved periodically, both during a session and during the vault lifecycle. This ensures that credential rotation, archival, or deletion propagates to running sessions without a restart.

To be notified if a credential is archived, deleted, or fails to refresh, you can subscribe to the vault and credential webhooks associated with those lifecycle changes.

EventTrigger
vault.archivedVault archived. A vault_credential.archived event is also emitted for each underlying credential.
vault.deletedVault deleted. A vault_credential.deleted event is also emitted for each underlying credential.
vault_credential.archivedCredential archived, either directly or as a result of vault archival.
vault_credential.deletedCredential deleted, either directly or as a result of vault deletion.
vault_credential.refresh_failedAn mcp_oauth credential cannot be refreshed (invalid refresh token, or irrecoverable error from the OAuth server).

For mcp_oauth credentials, re-resolution also refreshes the access token if it has expired. If the refresh fails, a vault_credential.refresh_failed event is emitted.

Diagnose an OAuth refresh failure

To diagnose why a refresh failed, call POST /v1/vaults/{vault_id}/credentials/{credential_id}/mcp_oauth_validate (or client.beta.vaults.credentials.mcp_oauth_validate(...) in the SDK). This lets you decide how to handle the failure; the right action depends on the error type.

The top-level status tells you what to do next:

  • valid: the token works; no action needed.
  • invalid: the grant is gone or the OAuth server rejected the refresh with a 4xx. Prompt the end user to re-authorize.
  • unknown: a transient error (5xx, 429, or network failure). Wait and retry.
ant beta:vaults:credentials mcp-oauth-validate \
  --vault-id "$VAULT_ID" \
  --credential-id "$CREDENTIAL_ID" \
  --transform status --raw-output  # "valid", "invalid", or "unknown"

The response is a vault_credential_validation object. mcp_probe includes the failed MCP handshake step; refresh includes the outcome of the attempted refresh.

{
  "type": "vault_credential_validation",
  "credential_id": "vcrd_01ABC...",
  "vault_id": "vlt_01XYZ...",
  "validated_at": "2026-04-29T17:12:00Z",
  "has_refresh_token": false,
  "status": "invalid",
  "mcp_probe": {
    "method": "initialize",
    "http_response": {
      "status_code": 401,
      "content_type": "application/json",
      "body": "{\"error\":\"invalid_token\"}",
      "body_truncated": false
    }
  },
  "refresh": {
    "status": "no_refresh_token",
    "http_response": null
  }
}

Other operations

  • List vaults or credentials: Paginated, newest first. Archived records are excluded by default (pass include_archived=true to include them).
  • Archive a vault: POST /v1/vaults/{id}/archive. Cascades to all credentials. Secrets are purged; records are retained for auditing. Future sessions referencing this vault fail; running sessions continue.
  • Archive a credential: POST /v1/vaults/{id}/credentials/{cred_id}/archive. Purges the secret payload; the credential key (mcp_server_url or secret_name) remains visible and is freed for a replacement credential.
  • Delete a vault or credential: Hard delete. The record is not retained. Use archive if you need an audit trail.

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