Prove
An approval that cannot be reused
After a yes, a short-lived signed token binds the approval to the exact action. Change anything and it fails.
Your agent presents the token
POST /payments/refundx-xevrion-token: xt_4c9…{ order: 88231, amount: 540 }// Change the amount to 541:→ rejected: action does not matchWhat the token locks
- Action
- refund.issue
- Amount
- £540
- Expires
- In 5 min
- Uses
- 1 of 1
Life of a token
- Person approves
- Token issued, 5 min
- Used once by your agent
- Second use refused
Why it matters
What proof-carrying tokens changes
- After a yes, a short-lived signed token is issued.
- It is bound to the exact action and payload.
- Change anything and your tool refuses to run.
- An approval is a message, not a permission.
- A tool can run something different after the yes.
- An old approval can be used again.
The resultOnly what was approved can run.
What you get
Proof-carrying tokens, in practice
Bound to the action
The token covers that payload only. A changed amount or target is refused.
Expires fast
A short window, so an old approval cannot be replayed later.
Single use
Once spent, it is spent. A second try is refused.
How it works
Step by step
- 1
Person approves
The decision is recorded.
- 2
Token issued
Signed, short-lived, one action.
- 3
Executor checks
Signature, payload, time, not used before.
- 4
Action runs
Or is refused, with a reason.
Questions
About proof-carrying tokens
Where is the token checked?
Before your action runs. Your executor checks the token and refuses on any mismatch.
What if the agent edits the action after approval?
The token no longer matches, so the executor refuses it.
Next
Works well with
Know what your agents did.
Start free. Guard your first agent in a few minutes, and keep a record anyone can check.
- Free plan, no card
- Signed, chained decisions
- Checked offline, without us
Signed decision
- Decision
- Approved, 2 of 2
- Action
- refund.issue, £540
- Rule
- Two reviewers must agree
- Sealed
- 14:09, key 7f2c
- Hash
- 5be2…7c44
Checked on your own machine
- Signature matches the public key
- Decision is in the log
- Every link before it adds up