For agents

An agent can hand over a credential without being able to read it back

x-tkn is callable by an agent today: a sandbox key with no signup, a public OpenAPI spec, and refusals that name the plan which would grant the capability. The local MCP server exposes create_secret, check_status, revoke_secret and claim_sandbox, with no read tool.

Read the MCP cookbook See pricing
No signup
Sandbox key, 100 operations, 24 hours
402
Refusals an agent can act on
No read tool
API and MCP
One-time handoff
Retrieval link
x-tkn.com/s/#7f3a9c1e…
one read expires in 24h unread
Encrypted before it left the sender
We hold ciphertext; the key stays in the link
Waiting for the one read…
Available now

The API is the agent interface

The API and the local MCP server are available.

  • An unauthenticated sandbox endpoint returns a working API key. No signup, no inbox, no CAPTCHA.
  • A public OpenAPI spec at https://x-tkn.com/openapi.json.
  • A paid capability refuses with 402, the capability name, the cheapest plan that grants it, and a checkout link a human can click.
  • Quota position on every metered response through x-rate-limit, x-rate-usage and x-rate-ceiling, including on the 429.
  • Passing your quota does not kill the integration: you are served to twice it, with three emails on the way.
Available now

Four tools, and no read tool

The local MCP server exposes create_secret, check_status, revoke_secret and claim_sandbox. Follow the MCP cookbook to install it and hand over a secret once.

  • There is no read_secret tool, and there will not be one.
  • The agent creates the handoff. The human, or the target system, consumes it.
  • An agent cannot exfiltrate through a tool it does not have.

We are second to market, so here is the precise difference

Vaulted ships an MCP server today. It is free, needs no account, installs with npx, and its source defines create_secret, view_secret, check_status and list_secrets. x-tkn ships create_secret, check_status, revoke_secret and claim_sandbox, with no tool to read a secret back.

The difference is view_secret. Their source implements it to decrypt a secret and hand it back to the agent, and the npm release, 0.1.6, still answers "not implemented yet" for it. Ours has no equivalent and is not designed to acquire one. If your threat model includes the agent itself, whether that is prompt injection, a compromised tool chain, or a transcript that outlives the task, then that is the distinction to weigh.

Two of our four tool names are also theirs, so the lists will be read side by side. That is the comparison we would rather you made than one we wrote for you.

Try it first

Call it before you commit to it

A sandbox key costs nothing and needs no account.

Read the API docs Compare with Vaulted