---
title: "Error reference: Delegation chain | KYA"
url: https://knowyouragent.ch/en/method/errors/delegation
lang: en
updated: 2026-10-12
license: © Innopulse Consulting GmbH
---

# Error reference: Delegation chain

Is every hop signed, connected without gaps and no broader than the previous one?

If an agent passes part of its authority on to another agent, a delegation chain arises. This check verifies each level: whether it is signed, whether it is bound to the next level's key and whether authority only narrows further down.

If there is no delegation, that is not an error. The check then reports that no delegation is present, and the result depends on the other checks.

A level that allows more than the previous one makes the chain invalid, even if all signatures hold.

## `no_delegation`

**No delegation chain: the principal mandated directly.**

**Cause:** The evidence contains no delegation. That is not an error but the most common situation: the agent acts directly for its principal.

**Fix:** Nothing to do. Delegations are needed only when an agent passes authority on to another agent.

## `delegation_broken`

**The delegation chain is broken or expired.**

**Cause:** A level of the delegation chain is not correctly connected to the next, for example because the signature is missing or does not match the previous level's key.

**Fix:** Create the chain anew so that every level is signed by the previous level's key and binds the next level's key.

## `delegation_scope_widened`

**A delegation hop widens the scope.**

**Cause:** A level of the delegation allows more than the previous one, such as a higher amount or more action types.

**Fix:** Delegate only authority that is narrower or equal. An expansion is not permitted and makes the chain invalid.

## `delegation_key_missing`

**A bound key is missing for a delegation hop.**

**Cause:** For one level of the delegation, the key with which it could be verified is missing.

**Fix:** Present all levels completely and make sure each level contains the key of the next.

## Common situations

**Not an error:** the code “no delegation” appears for most evidence. It only means that the agent acts directly for its principal.

**Widened authority:** if a main agent gives a specialist agent a higher amount than it may use itself, the chain is invalid. Check the logic that creates delegations.

**Incomplete chain:** if only the last level is presented, the keys of the previous levels are missing. Present the chain in full.

## How to test this check

The public test vectors contain delegation chains, including a chain with widened authority. Verify them with the kya-verify command line to see the codes for broken and widened chains. Each vector states the expected verdict and the expected code.

[Error reference](https://knowyouragent.ch/en/method/errors) · [Checks](https://knowyouragent.ch/en/method/checks)

---
Quelle: https://knowyouragent.ch/en/method/errors/delegation · KYA – Know Your Agent